MinIO Bucket Notification Guide Slack

Events occurring on objects in a bucket can be monitored using bucket event notifications. Event types supported by MinIO server are

Supported Event Types
s3:ObjectCreated:Put s3:ObjectCreated:CompleteMultipartUpload s3:ObjectAccessed:Head
s3:ObjectCreated:Post s3:ObjectRemoved:Delete
s3:ObjectCreated:Copy s3:ObjectAccessed:Get

Use client tools like mc to set and listen for event notifications using the event sub-command. MinIO SDK's BucketNotification APIs can also be used. The notification message MinIO sends to publish an event is a JSON message with the following structure.

Bucket events can be published to the following targets:

Supported Notification Targets
AMQP Redis MySQL
MQTT NATS Apache Kafka
Elasticsearch PostgreSQL Webhooks
NSQ

Prerequisites

$ mc admin config get myminio | grep notify
notify_webhook        publish bucket notifications to webhook endpoints
notify_amqp           publish bucket notifications to AMQP endpoints
notify_kafka          publish bucket notifications to Kafka endpoints
notify_mqtt           publish bucket notifications to MQTT endpoints
notify_nats           publish bucket notifications to NATS endpoints
notify_nsq            publish bucket notifications to NSQ endpoints
notify_mysql          publish bucket notifications to MySQL databases
notify_postgres       publish bucket notifications to Postgres databases
notify_elasticsearch  publish bucket notifications to Elasticsearch endpoints
notify_redis          publish bucket notifications to Redis datastores

NOTE:

  • '*' at the end of arg means its mandatory.
  • '*' at the end of the values, means its the default value for the arg.
  • When configured using environment variables, the :name can be specified using this format MINIO_NOTIFY_WEBHOOK_ENABLE_<name>.

Publish MinIO events via AMQP

Install RabbitMQ from here.

Step 1: Add AMQP endpoint to MinIO

The AMQP configuration is located under the sub-system notify_amqp top-level key. Create a configuration key-value pair here for your AMQP instance. The key is a name for your AMQP endpoint, and the value is a collection of key-value parameters described in the table below.

KEY:
notify_amqp[:name]  publish bucket notifications to AMQP endpoints

ARGS:
url*           (url)       AMQP server endpoint e.g. `amqp://myuser:mypassword@localhost:5672`
exchange       (string)    name of the AMQP exchange
exchange_type  (string)    AMQP exchange type
routing_key    (string)    routing key for publishing
mandatory      (on|off)    quietly ignore undelivered messages when set to 'off', default is 'on'
durable        (on|off)    persist queue across broker restarts when set to 'on', default is 'off'
no_wait        (on|off)    non-blocking message delivery when set to 'on', default is 'off'
internal       (on|off)    set to 'on' for exchange to be not used directly by publishers, but only when bound to other exchanges
auto_deleted   (on|off)    auto delete queue when set to 'on', when there are no consumers
delivery_mode  (number)    set to '1' for non-persistent or '2' for persistent queue
queue_dir      (path)      staging dir for undelivered messages e.g. '/home/events'
queue_limit    (number)    maximum limit for undelivered messages, defaults to '100000'
comment        (sentence)  optionally add a comment to this setting

Or environment variables

KEY:
notify_amqp[:name]  publish bucket notifications to AMQP endpoints

ARGS:
MINIO_NOTIFY_AMQP_ENABLE*        (on|off)    enable notify_amqp target, default is 'off'
MINIO_NOTIFY_AMQP_URL*           (url)       AMQP server endpoint e.g. `amqp://myuser:mypassword@localhost:5672`
MINIO_NOTIFY_AMQP_EXCHANGE       (string)    name of the AMQP exchange
MINIO_NOTIFY_AMQP_EXCHANGE_TYPE  (string)    AMQP exchange type
MINIO_NOTIFY_AMQP_ROUTING_KEY    (string)    routing key for publishing
MINIO_NOTIFY_AMQP_MANDATORY      (on|off)    quietly ignore undelivered messages when set to 'off', default is 'on'
MINIO_NOTIFY_AMQP_DURABLE        (on|off)    persist queue across broker restarts when set to 'on', default is 'off'
MINIO_NOTIFY_AMQP_NO_WAIT        (on|off)    non-blocking message delivery when set to 'on', default is 'off'
MINIO_NOTIFY_AMQP_INTERNAL       (on|off)    set to 'on' for exchange to be not used directly by publishers, but only when bound to other exchanges
MINIO_NOTIFY_AMQP_AUTO_DELETED   (on|off)    auto delete queue when set to 'on', when there are no consumers
MINIO_NOTIFY_AMQP_DELIVERY_MODE  (number)    set to '1' for non-persistent or '2' for persistent queue
MINIO_NOTIFY_AMQP_QUEUE_DIR      (path)      staging dir for undelivered messages e.g. '/home/events'
MINIO_NOTIFY_AMQP_QUEUE_LIMIT    (number)    maximum limit for undelivered messages, defaults to '100000'
MINIO_NOTIFY_AMQP_COMMENT        (sentence)  optionally add a comment to this setting

MinIO supports persistent event store. The persistent store will backup events when the AMQP broker goes offline and replays it when the broker comes back online. The event store can be configured by setting the directory path in queue_dir field and the maximum limit of events in the queue_dir in queue_limit field. For eg, the queue_dir can be /home/events and queue_limit can be 1000. By default, the queue_limit is set to 100000.

To update the configuration, use mc admin config get notify_amqp command to get the current configuration for notify_amqp.

$ mc admin config get myminio/ notify_amqp
notify_amqp:1 delivery_mode="0" exchange_type="" no_wait="off" queue_dir="" queue_limit="0"  url="" auto_deleted="off" durable="off" exchange="" internal="off" mandatory="off" routing_key=""

Use mc admin config set command to update the configuration for the deployment.Restart the MinIO server to put the changes into effect. The server will print a line like SQS ARNs: arn:minio:sqs::1:amqp at start-up if there were no errors.

An example configuration for RabbitMQ is shown below:

$ mc admin config set myminio/ notify_amqp:1 exchange="bucketevents" exchange_type="fanout" mandatory="false" no_wait="false"  url="amqp://myuser:mypassword@localhost:5672" auto_deleted="false" delivery_mode="0" durable="false" internal="false" routing_key="bucketlogs"

MinIO supports all the exchanges available in RabbitMQ. For this setup, we are using fanout exchange.

Note that, you can add as many AMQP server endpoint configurations as needed by providing an identifier (like "1" in the example above) for the AMQP instance and an object of per-server configuration parameters.

Step 2: Enable bucket notification using MinIO client

We will enable bucket event notification to trigger whenever a JPEG image is uploaded or deleted images bucket on myminio server. Here ARN value is arn:minio:sqs::1:amqp. To understand more about ARN please follow AWS ARN documentation.

mc mb myminio/images
mc event add myminio/images arn:minio:sqs::1:amqp --suffix .jpg
mc event list myminio/images
arn:minio:sqs::1:amqp s3:ObjectCreated:*,s3:ObjectRemoved:* Filter: suffix=”.jpg”

Step 3: Test on RabbitMQ

The python program below waits on the queue exchange bucketevents and prints event notifications on the console. We use Pika Python Client library to do this.

#!/usr/bin/env python
import pika

connection = pika.BlockingConnection(pika.ConnectionParameters(
        host='localhost'))
channel = connection.channel()

channel.exchange_declare(exchange='bucketevents',
                         exchange_type='fanout')

result = channel.queue_declare(exclusive=False)
queue_name = result.method.queue

channel.queue_bind(exchange='bucketevents',
                   queue=queue_name)

print(' [*] Waiting for logs. To exit press CTRL+C')

def callback(ch, method, properties, body):
    print(" [x] %r" % body)

channel.basic_consume(callback,
                      queue=queue_name,
                      no_ack=False)

channel.start_consuming()

Execute this example python program to watch for RabbitMQ events on the console.

python rabbit.py

Open another terminal and upload a JPEG image into images bucket.

mc cp myphoto.jpg myminio/images

You should receive the following event notification via RabbitMQ once the upload completes.

python rabbit.py
'{"Records":[{"eventVersion":"2.0","eventSource":"aws:s3","awsRegion":"","eventTime":"2016–09–08T22:34:38.226Z","eventName":"s3:ObjectCreated:Put","userIdentity":{"principalId":"minio"},"requestParameters":{"sourceIPAddress":"10.1.10.150:44576"},"responseElements":{},"s3":{"s3SchemaVersion":"1.0","configurationId":"Config","bucket":{"name":"images","ownerIdentity":{"principalId":"minio"},"arn":"arn:aws:s3:::images"},"object":{"key":"myphoto.jpg","size":200436,"sequencer":"147279EAF9F40933"}}}],"level":"info","msg":"","time":"2016–09–08T15:34:38–07:00"}'

Publish MinIO events MQTT

Install an MQTT Broker from here.

Step 1: Add MQTT endpoint to MinIO

The MQTT configuration is located as notify_mqtt key. Create a configuration key-value pair here for your MQTT instance. The key is a name for your MQTT endpoint, and the value is a collection of key-value parameters described in the table below.

KEY:
notify_mqtt[:name]  publish bucket notifications to MQTT endpoints

ARGS:
broker*              (uri)       MQTT server endpoint e.g. `tcp://localhost:1883`
topic*               (string)    name of the MQTT topic to publish
username             (string)    MQTT username
password             (string)    MQTT password
qos                  (number)    set the quality of service priority, defaults to '0'
keep_alive_interval  (duration)  keep-alive interval for MQTT connections in s,m,h,d
reconnect_interval   (duration)  reconnect interval for MQTT connections in s,m,h,d
queue_dir            (path)      staging dir for undelivered messages e.g. '/home/events'
queue_limit          (number)    maximum limit for undelivered messages, defaults to '100000'
comment              (sentence)  optionally add a comment to this setting

or environment variables

KEY:
notify_mqtt[:name]  publish bucket notifications to MQTT endpoints

ARGS:
MINIO_NOTIFY_MQTT_ENABLE*              (on|off)    enable notify_mqtt target, default is 'off'
MINIO_NOTIFY_MQTT_BROKER*              (uri)       MQTT server endpoint e.g. `tcp://localhost:1883`
MINIO_NOTIFY_MQTT_TOPIC*               (string)    name of the MQTT topic to publish
MINIO_NOTIFY_MQTT_USERNAME             (string)    MQTT username
MINIO_NOTIFY_MQTT_PASSWORD             (string)    MQTT password
MINIO_NOTIFY_MQTT_QOS                  (number)    set the quality of service priority, defaults to '0'
MINIO_NOTIFY_MQTT_KEEP_ALIVE_INTERVAL  (duration)  keep-alive interval for MQTT connections in s,m,h,d
MINIO_NOTIFY_MQTT_RECONNECT_INTERVAL   (duration)  reconnect interval for MQTT connections in s,m,h,d
MINIO_NOTIFY_MQTT_QUEUE_DIR            (path)      staging dir for undelivered messages e.g. '/home/events'
MINIO_NOTIFY_MQTT_QUEUE_LIMIT          (number)    maximum limit for undelivered messages, defaults to '100000'
MINIO_NOTIFY_MQTT_COMMENT              (sentence)  optionally add a comment to this setting

MinIO supports persistent event store. The persistent store will backup events when the MQTT broker goes offline and replays it when the broker comes back online. The event store can be configured by setting the directory path in queue_dir field and the maximum limit of events in the queue_dir in queue_limit field. For eg, the queue_dir can be /home/events and queue_limit can be 1000. By default, the queue_limit is set to 100000.

To update the configuration, use mc admin config get command to get the current configuration.

$ mc admin config get myminio/ notify_mqtt
notify_mqtt:1 broker="" password="" queue_dir="" queue_limit="0" reconnect_interval="0s"  keep_alive_interval="0s" qos="0" topic="" username=""

Use mc admin config set command to update the configuration for the deployment. Restart the MinIO server to put the changes into effect. The server will print a line like SQS ARNs: arn:minio:sqs::1:mqtt at start-up if there were no errors.

$ mc admin config set myminio notify_mqtt:1 broker="tcp://localhost:1883" password="" queue_dir="" queue_limit="0" reconnect_interval="0s"  keep_alive_interval="0s" qos="1" topic="minio" username=""

MinIO supports any MQTT server that supports MQTT 3.1 or 3.1.1 and can connect to them over TCP, TLS, or a Websocket connection using tcp://, tls://, or ws:// respectively as the scheme for the broker url. See the Go Client documentation for more information.

Note that, you can add as many MQTT server endpoint configurations as needed by providing an identifier (like "1" in the example above) for the MQTT instance and an object of per-server configuration parameters.

Step 2: Enable bucket notification using MinIO client

We will enable bucket event notification to trigger whenever a JPEG image is uploaded or deleted images bucket on myminio server. Here ARN value is arn:minio:sqs::1:mqtt.

mc mb myminio/images
mc event add  myminio/images arn:minio:sqs::1:mqtt --suffix .jpg
mc event list myminio/images
arn:minio:sqs::1:amqp s3:ObjectCreated:*,s3:ObjectRemoved:* Filter: suffix=”.jpg”

Step 3: Test on MQTT

The python program below waits on mqtt topic /minio and prints event notifications on the console. We use paho-mqtt library to do this.

#!/usr/bin/env python3
from __future__ import print_function
import paho.mqtt.client as mqtt

# This is the Subscriber

def on_connect(client, userdata, flags, rc):
  print("Connected with result code "+str(rc))
  # qos level is set to 1
  client.subscribe("minio", 1)

def on_message(client, userdata, msg):
    print(msg.payload)

# client_id is a randomly generated unique ID for the mqtt broker to identify the connection.
client = mqtt.Client(client_id="myclientid",clean_session=False)

client.on_connect = on_connect
client.on_message = on_message

client.connect("localhost",1883,60)
client.loop_forever()

Execute this example python program to watch for MQTT events on the console.

python mqtt.py

Open another terminal and upload a JPEG image into images bucket.

mc cp myphoto.jpg myminio/images

You should receive the following event notification via MQTT once the upload completes.

python mqtt.py
{“Records”:[{“eventVersion”:”2.0",”eventSource”:”aws:s3",”awsRegion”:”",”eventTime”:”2016–09–08T22:34:38.226Z”,”eventName”:”s3:ObjectCreated:Put”,”userIdentity”:{“principalId”:”minio”},”requestParameters”:{“sourceIPAddress”:”10.1.10.150:44576"},”responseElements”:{},”s3":{“s3SchemaVersion”:”1.0",”configurationId”:”Config”,”bucket”:{“name”:”images”,”ownerIdentity”:{“principalId”:”minio”},”arn”:”arn:aws:s3:::images”},”object”:{“key”:”myphoto.jpg”,”size”:200436,”sequencer”:”147279EAF9F40933"}}}],”level”:”info”,”msg”:””,”time”:”2016–09–08T15:34:38–07:00"}

Publish MinIO events via Elasticsearch

Install Elasticsearch server.

This notification target supports two formats: namespace and access.

When the namespace format is used, MinIO synchronizes objects in the bucket with documents in the index. For each event in the MinIO, the server creates a document with the bucket and object name from the event as the document ID. Other details of the event are stored in the body of the document. Thus if an existing object is over-written in MinIO, the corresponding document in the Elasticsearch index is updated. If an object is deleted, the corresponding document is deleted from the index.

When the access format is used, MinIO appends events as documents in an Elasticsearch index. For each event, a document with the event details, with the timestamp of document set to the event's timestamp is appended to an index. The ID of the documented is randomly generated by Elasticsearch. No documents are deleted or modified in this format.

The steps below show how to use this notification target in namespace format. The other format is very similar and is omitted for brevity.

Step 1: Ensure minimum requirements are met

MinIO requires a 5.x series version of Elasticsearch. This is the latest major release series. Elasticsearch provides version upgrade migration guidelines here.

Step 2: Add Elasticsearch endpoint to MinIO

The Elasticsearch configuration is located in the notify_elasticsearch key. Create a configuration key-value pair here for your Elasticsearch instance. The key is a name for your Elasticsearch endpoint, and the value is a collection of key-value parameters described in the table below.

KEY:
notify_elasticsearch[:name]  publish bucket notifications to Elasticsearch endpoints

ARGS:
url*         (url)                Elasticsearch server's address, with optional authentication info
index*       (string)             Elasticsearch index to store/update events, index is auto-created
format*      (namespace*|access)  'namespace' reflects current bucket/object list and 'access' reflects a journal of object operations, defaults to 'namespace'
queue_dir    (path)               staging dir for undelivered messages e.g. '/home/events'
queue_limit  (number)             maximum limit for undelivered messages, defaults to '100000'
comment      (sentence)           optionally add a comment to this setting

or environment variables

KEY:
notify_elasticsearch[:name]  publish bucket notifications to Elasticsearch endpoints

ARGS:
MINIO_NOTIFY_ELASTICSEARCH_ENABLE*      (on|off)             enable notify_elasticsearch target, default is 'off'
MINIO_NOTIFY_ELASTICSEARCH_URL*         (url)                Elasticsearch server's address, with optional authentication info
MINIO_NOTIFY_ELASTICSEARCH_INDEX*       (string)             Elasticsearch index to store/update events, index is auto-created
MINIO_NOTIFY_ELASTICSEARCH_FORMAT*      (namespace*|access)  'namespace' reflects current bucket/object list and 'access' reflects a journal of object operations, defaults to 'namespace'
MINIO_NOTIFY_ELASTICSEARCH_QUEUE_DIR    (path)               staging dir for undelivered messages e.g. '/home/events'
MINIO_NOTIFY_ELASTICSEARCH_QUEUE_LIMIT  (number)             maximum limit for undelivered messages, defaults to '100000'
MINIO_NOTIFY_ELASTICSEARCH_COMMENT      (sentence)           optionally add a comment to this setting

For example: http://localhost:9200 or with authentication info http://elastic:MagicWord@127.0.0.1:9200.

MinIO supports persistent event store. The persistent store will backup events when the Elasticsearch broker goes offline and replays it when the broker comes back online. The event store can be configured by setting the directory path in queue_dir field and the maximum limit of events in the queue_dir in queue_limit field. For eg, the queue_dir can be /home/events and queue_limit can be 1000. By default, the queue_limit is set to 100000.

If Elasticsearch has authentication enabled, the credentials can be supplied to MinIO via the url parameter formatted as PROTO://USERNAME:PASSWORD@ELASTICSEARCH_HOST:PORT.

To update the configuration, use mc admin config get command to get the current configuration.

$ mc admin config get myminio/ notify_elasticsearch
notify_elasticsearch:1 queue_limit="0"  url="" format="namespace" index="" queue_dir=""

Use mc admin config set command to update the configuration for the deployment. Restart the MinIO server to put the changes into effect. The server will print a line like SQS ARNs: arn:minio:sqs::1:elasticsearch at start-up if there were no errors.

$ mc admin config set myminio notify_elasticsearch:1 queue_limit="0"  url="http://127.0.0.1:9200" format="namespace" index="minio_events" queue_dir=""

Note that, you can add as many Elasticsearch server endpoint configurations as needed by providing an identifier (like "1" in the example above) for the Elasticsearch instance and an object of per-server configuration parameters.

Step 3: Enable bucket notification using MinIO client

We will now enable bucket event notifications on a bucket named images. Whenever a JPEG image is created/overwritten, a new document is added or an existing document is updated in the Elasticsearch index configured above. When an existing object is deleted, the corresponding document is deleted from the index. Thus, the rows in the Elasticsearch index, reflect the .jpg objects in the images bucket.

To configure this bucket notification, we need the ARN printed by MinIO in the previous step. Additional information about ARN is available here.

With the mc tool, the configuration is very simple to add. Let us say that the MinIO server is aliased as myminio in our mc configuration. Execute the following:

mc mb myminio/images
mc event add  myminio/images arn:minio:sqs::1:elasticsearch --suffix .jpg
mc event list myminio/images
arn:minio:sqs::1:elasticsearch s3:ObjectCreated:*,s3:ObjectRemoved:* Filter: suffix=”.jpg”

Step 4: Test on Elasticsearch

Upload a JPEG image into images bucket.

mc cp myphoto.jpg myminio/images

Use curl to view contents of minio_events index.

$ curl  "http://localhost:9200/minio_events/_search?pretty=true"
{
  "took" : 40,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "failed" : 0
  },
  "hits" : {
    "total" : 1,
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "minio_events",
        "_type" : "event",
        "_id" : "images/myphoto.jpg",
        "_score" : 1.0,
        "_source" : {
          "Records" : [
            {
              "eventVersion" : "2.0",
              "eventSource" : "minio:s3",
              "awsRegion" : "",
              "eventTime" : "2017-03-30T08:00:41Z",
              "eventName" : "s3:ObjectCreated:Put",
              "userIdentity" : {
                "principalId" : "minio"
              },
              "requestParameters" : {
                "sourceIPAddress" : "127.0.0.1:38062"
              },
              "responseElements" : {
                "x-amz-request-id" : "14B09A09703FC47B",
                "x-minio-origin-endpoint" : "http://192.168.86.115:9000"
              },
              "s3" : {
                "s3SchemaVersion" : "1.0",
                "configurationId" : "Config",
                "bucket" : {
                  "name" : "images",
                  "ownerIdentity" : {
                    "principalId" : "minio"
                  },
                  "arn" : "arn:aws:s3:::images"
                },
                "object" : {
                  "key" : "myphoto.jpg",
                  "size" : 6474,
                  "eTag" : "a3410f4f8788b510d6f19c5067e60a90",
                  "sequencer" : "14B09A09703FC47B"
                }
              },
              "source" : {
                "host" : "127.0.0.1",
                "port" : "38062",
                "userAgent" : "MinIO (linux; amd64) minio-go/2.0.3 mc/2017-02-15T17:57:25Z"
              }
            }
          ]
        }
      }
    ]
  }
}

This output shows that a document has been created for the event in Elasticsearch.

Here we see that the document ID is the bucket and object name. In case access format was used, the document ID would be automatically generated by Elasticsearch.

Publish MinIO events via Redis

Install Redis server. For illustrative purposes, we have set the database password as "yoursecret".

This notification target supports two formats: namespace and access.

When the namespace format is used, MinIO synchronizes objects in the bucket with entries in a hash. For each entry, the key is formatted as "bucketName/objectName" for an object that exists in the bucket, and the value is the JSON-encoded event data about the operation that created/replaced the object in MinIO. When objects are updated or deleted, the corresponding entry in the hash is also updated or deleted.

When the access format is used, MinIO appends events to a list using RPUSH. Each item in the list is a JSON encoded list with two items, where the first item is a timestamp string, and the second item is a JSON object containing event data about the operation that happened in the bucket. No entries appended to the list are updated or deleted by MinIO in this format.

The steps below show how to use this notification target in namespace and access format.

Step 1: Add Redis endpoint to MinIO

The MinIO server configuration file is stored on the backend in json format.The Redis configuration is located in the redis key under the notify top-level key. Create a configuration key-value pair here for your Redis instance. The key is a name for your Redis endpoint, and the value is a collection of key-value parameters described in the table below.

KEY:
notify_redis[:name]  publish bucket notifications to Redis datastores

ARGS:
address*     (address)            Redis server's address. For example: `localhost:6379`
key*         (string)             Redis key to store/update events, key is auto-created
format*      (namespace*|access)  'namespace' reflects current bucket/object list and 'access' reflects a journal of object operations, defaults to 'namespace'
password     (string)             Redis server password
queue_dir    (path)               staging dir for undelivered messages e.g. '/home/events'
queue_limit  (number)             maximum limit for undelivered messages, defaults to '100000'
comment      (sentence)           optionally add a comment to this setting

or environment variables

KEY:
notify_redis[:name]  publish bucket notifications to Redis datastores

ARGS:
MINIO_NOTIFY_REDIS_ENABLE*      (on|off)             enable notify_redis target, default is 'off'
MINIO_NOTIFY_REDIS_KEY*         (string)             Redis key to store/update events, key is auto-created
MINIO_NOTIFY_REDIS_FORMAT*      (namespace*|access)  'namespace' reflects current bucket/object list and 'access' reflects a journal of object operations, defaults to 'namespace'
MINIO_NOTIFY_REDIS_PASSWORD     (string)             Redis server password
MINIO_NOTIFY_REDIS_QUEUE_DIR    (path)               staging dir for undelivered messages e.g. '/home/events'
MINIO_NOTIFY_REDIS_QUEUE_LIMIT  (number)             maximum limit for undelivered messages, defaults to '100000'
MINIO_NOTIFY_REDIS_COMMENT      (sentence)           optionally add a comment to this setting

MinIO supports persistent event store. The persistent store will backup events when the Redis broker goes offline and replays it when the broker comes back online. The event store can be configured by setting the directory path in queue_dir field and the maximum limit of events in the queue_dir in queue_limit field. For eg, the queue_dir can be /home/events and queue_limit can be 1000. By default, the queue_limit is set to 100000.

To update the configuration, use mc admin config get command to get the current configuration.

$ mc admin config get myminio/ notify_redis
notify_redis:1 address="" format="namespace" key="" password="" queue_dir="" queue_limit="0"

Use mc admin config set command to update the configuration for the deployment.Restart the MinIO server to put the changes into effect. The server will print a line like SQS ARNs: arn:minio:sqs::1:redis at start-up if there were no errors.

$ mc admin config set myminio/ notify_redis:1 address="127.0.0.1:6379" format="namespace" key="bucketevents" password="yoursecret" queue_dir="" queue_limit="0"

Note that, you can add as many Redis server endpoint configurations as needed by providing an identifier (like "1" in the example above) for the Redis instance and an object of per-server configuration parameters.

Step 2: Enable bucket notification using MinIO client

We will now enable bucket event notifications on a bucket named images. Whenever a JPEG image is created/overwritten, a new key is added or an existing key is updated in the Redis hash configured above. When an existing object is deleted, the corresponding key is deleted from the Redis hash. Thus, the rows in the Redis hash, reflect the .jpg objects in the images bucket.

To configure this bucket notification, we need the ARN printed by MinIO in the previous step. Additional information about ARN is available here.

With the mc tool, the configuration is very simple to add. Let us say that the MinIO server is aliased as myminio in our mc configuration. Execute the following:

mc mb myminio/images
mc event add myminio/images arn:minio:sqs::1:redis --suffix .jpg
mc event list myminio/images
arn:minio:sqs::1:redis s3:ObjectCreated:*,s3:ObjectRemoved:* Filter: suffix=”.jpg”

Step 3: Test on Redis

Start the redis-cli Redis client program to inspect the contents in Redis. Run the monitor Redis command. This prints each operation performed on Redis as it occurs.

redis-cli -a yoursecret
127.0.0.1:6379> monitor
OK

Open another terminal and upload a JPEG image into images bucket.

mc cp myphoto.jpg myminio/images

In the previous terminal, you will now see the operation that MinIO performs on Redis:

127.0.0.1:6379> monitor
OK
1490686879.650649 [0 172.17.0.1:44710] "PING"
1490686879.651061 [0 172.17.0.1:44710] "HSET" "minio_events" "images/myphoto.jpg" "{\"Records\":[{\"eventVersion\":\"2.0\",\"eventSource\":\"minio:s3\",\"awsRegion\":\"\",\"eventTime\":\"2017-03-28T07:41:19Z\",\"eventName\":\"s3:ObjectCreated:Put\",\"userIdentity\":{\"principalId\":\"minio\"},\"requestParameters\":{\"sourceIPAddress\":\"127.0.0.1:52234\"},\"responseElements\":{\"x-amz-request-id\":\"14AFFBD1ACE5F632\",\"x-minio-origin-endpoint\":\"http://192.168.86.115:9000\"},\"s3\":{\"s3SchemaVersion\":\"1.0\",\"configurationId\":\"Config\",\"bucket\":{\"name\":\"images\",\"ownerIdentity\":{\"principalId\":\"minio\"},\"arn\":\"arn:aws:s3:::images\"},\"object\":{\"key\":\"myphoto.jpg\",\"size\":2586,\"eTag\":\"5d284463f9da279f060f0ea4d11af098\",\"sequencer\":\"14AFFBD1ACE5F632\"}},\"source\":{\"host\":\"127.0.0.1\",\"port\":\"52234\",\"userAgent\":\"MinIO (linux; amd64) minio-go/2.0.3 mc/2017-02-15T17:57:25Z\"}}]}"

Here we see that MinIO performed HSET on minio_events key.

In case, access format was used, then minio_events would be a list, and the MinIO server would have performed an RPUSH to append to the list. A consumer of this list would ideally use BLPOP to remove list items from the left-end of the list.

Publish MinIO events via NATS

Install NATS from here.

Step 1: Add NATS endpoint to MinIO

MinIO supports persistent event store. The persistent store will backup events when the NATS broker goes offline and replays it when the broker comes back online. The event store can be configured by setting the directory path in queue_dir field and the maximum limit of events in the queue_dir in queue_limit field. For eg, the queue_dir can be /home/events and queue_limit can be 1000. By default, the queue_limit is set to 100000.

KEY:
notify_nats[:name]  publish bucket notifications to NATS endpoints

ARGS:
address*                          (address)   NATS server address e.g. '0.0.0.0:4222'
subject*                          (string)    NATS subscription subject
username                          (string)    NATS username
password                          (string)    NATS password
token                             (string)    NATS token
tls                               (on|off)    set to 'on' to enable TLS
tls_skip_verify                   (on|off)    trust server TLS without verification, defaults to "on" (verify)
ping_interval                     (duration)  client ping commands interval in s,m,h,d. Disabled by default
streaming                         (on|off)    set to 'on', to use streaming NATS server
streaming_async                   (on|off)    set to 'on', to enable asynchronous publish
streaming_max_pub_acks_in_flight  (number)    number of messages to publish without waiting for ACKs
streaming_cluster_id              (string)    unique ID for NATS streaming cluster
cert_authority                    (string)    path to certificate chain of the target NATS server
client_cert                       (string)    client cert for NATS mTLS auth
client_key                        (string)    client cert key for NATS mTLS auth
queue_dir                         (path)      staging dir for undelivered messages e.g. '/home/events'
queue_limit                       (number)    maximum limit for undelivered messages, defaults to '100000'
comment                           (sentence)  optionally add a comment to this setting

or environment variables

KEY:
notify_nats[:name]  publish bucket notifications to NATS endpoints

ARGS:
MINIO_NOTIFY_NATS_ENABLE*                           (on|off)    enable notify_nats target, default is 'off'
MINIO_NOTIFY_NATS_ADDRESS*                          (address)   NATS server address e.g. '0.0.0.0:4222'
MINIO_NOTIFY_NATS_SUBJECT*                          (string)    NATS subscription subject
MINIO_NOTIFY_NATS_USERNAME                          (string)    NATS username
MINIO_NOTIFY_NATS_PASSWORD                          (string)    NATS password
MINIO_NOTIFY_NATS_TOKEN                             (string)    NATS token
MINIO_NOTIFY_NATS_TLS                               (on|off)    set to 'on' to enable TLS
MINIO_NOTIFY_NATS_TLS_SKIP_VERIFY                   (on|off)    trust server TLS without verification, defaults to "on" (verify)
MINIO_NOTIFY_NATS_PING_INTERVAL                     (duration)  client ping commands interval in s,m,h,d. Disabled by default
MINIO_NOTIFY_NATS_STREAMING                         (on|off)    set to 'on', to use streaming NATS server
MINIO_NOTIFY_NATS_STREAMING_ASYNC                   (on|off)    set to 'on', to enable asynchronous publish
MINIO_NOTIFY_NATS_STREAMING_MAX_PUB_ACKS_IN_FLIGHT  (number)    number of messages to publish without waiting for ACKs
MINIO_NOTIFY_NATS_STREAMING_CLUSTER_ID              (string)    unique ID for NATS streaming cluster
MINIO_NOTIFY_NATS_CERT_AUTHORITY                    (string)    path to certificate chain of the target NATS server
MINIO_NOTIFY_NATS_CLIENT_CERT                       (string)    client cert for NATS mTLS auth
MINIO_NOTIFY_NATS_CLIENT_KEY                        (string)    client cert key for NATS mTLS auth
MINIO_NOTIFY_NATS_QUEUE_DIR                         (path)      staging dir for undelivered messages e.g. '/home/events'
MINIO_NOTIFY_NATS_QUEUE_LIMIT                       (number)    maximum limit for undelivered messages, defaults to '100000'
MINIO_NOTIFY_NATS_COMMENT                           (sentence)  optionally add a comment to this setting

To update the configuration, use mc admin config get command to get the current configuration file for the minio deployment.

$ mc admin config get myminio/ notify_nats
notify_nats:1 password="yoursecret" streaming_max_pub_acks_in_flight="10" subject="" address="0.0.0.0:4222"  token="" username="yourusername" ping_interval="0" queue_limit="0" tls="off" tls_skip_verify="off" streaming_async="on" queue_dir="" streaming_cluster_id="test-cluster" streaming_enable="on"

Use mc admin config set command to update the configuration for the deployment.Restart MinIO server to reflect config changes. bucketevents is the subject used by NATS in this example.

$ mc admin config set myminio notify_nats:1 password="yoursecret" streaming_max_pub_acks_in_flight="10" subject="" address="0.0.0.0:4222"  token="" username="yourusername" ping_interval="0" queue_limit="0" tls="off" streaming_async="on" queue_dir="" streaming_cluster_id="test-cluster" streaming_enable="on"

MinIO server also supports NATS Streaming mode that offers additional functionality like At-least-once-delivery, and Publisher rate limiting. To configure MinIO server to send notifications to NATS Streaming server, update the MinIO server configuration file as follows:

Read more about sections cluster_id, client_id on NATS documentation. Section maxPubAcksInflight is explained here.

Step 2: Enable bucket notification using MinIO client

We will enable bucket event notification to trigger whenever a JPEG image is uploaded or deleted from images bucket on myminio server. Here ARN value is arn:minio:sqs::1:nats. To understand more about ARN please follow AWS ARN documentation.

mc mb myminio/images
mc event add myminio/images arn:minio:sqs::1:nats --suffix .jpg
mc event list myminio/images
arn:minio:sqs::1:nats s3:ObjectCreated:*,s3:ObjectRemoved:* Filter: suffix=”.jpg”

Step 3: Test on NATS

If you use NATS server, check out this sample program below to log the bucket notification added to NATS.

package main

// Import Go and NATS packages
import (
    "log"
    "runtime"

    "github.com/nats-io/nats.go"
)

func main() {

    // Create server connection
    natsConnection, _ := nats.Connect("nats://yourusername:yoursecret@localhost:4222")
    log.Println("Connected")

    // Subscribe to subject
    log.Printf("Subscribing to subject 'bucketevents'\n")
    natsConnection.Subscribe("bucketevents", func(msg *nats.Msg) {

        // Handle the message
        log.Printf("Received message '%s\n", string(msg.Data)+"'")
    })

    // Keep the connection alive
    runtime.Goexit()
}
go run nats.go
2016/10/12 06:39:18 Connected
2016/10/12 06:39:18 Subscribing to subject 'bucketevents'

Open another terminal and upload a JPEG image into images bucket.

mc cp myphoto.jpg myminio/images

The example nats.go program prints event notification to console.

go run nats.go
2016/10/12 06:51:26 Connected
2016/10/12 06:51:26 Subscribing to subject 'bucketevents'
2016/10/12 06:51:33 Received message '{"EventType":"s3:ObjectCreated:Put","Key":"images/myphoto.jpg","Records":[{"eventVersion":"2.0","eventSource":"aws:s3","awsRegion":"","eventTime":"2016-10-12T13:51:33Z","eventName":"s3:ObjectCreated:Put","userIdentity":{"principalId":"minio"},"requestParameters":{"sourceIPAddress":"[::1]:57106"},"responseElements":{},"s3":{"s3SchemaVersion":"1.0","configurationId":"Config","bucket":{"name":"images","ownerIdentity":{"principalId":"minio"},"arn":"arn:aws:s3:::images"},"object":{"key":"myphoto.jpg","size":56060,"eTag":"1d97bf45ecb37f7a7b699418070df08f","sequencer":"147CCD1AE054BFD0"}}}],"level":"info","msg":"","time":"2016-10-12T06:51:33-07:00"}

If you use NATS Streaming server, check out this sample program below to log the bucket notification added to NATS.

package main

// Import Go and NATS packages
import (
    "fmt"
    "runtime"

    "github.com/nats-io/stan.go"
)

func main() {

    var stanConnection stan.Conn

    subscribe := func() {
        fmt.Printf("Subscribing to subject 'bucketevents'\n")
        stanConnection.Subscribe("bucketevents", func(m *stan.Msg) {

            // Handle the message
            fmt.Printf("Received a message: %s\n", string(m.Data))
        })
    }


    stanConnection, _ = stan.Connect("test-cluster", "test-client", stan.NatsURL("nats://yourusername:yoursecret@0.0.0.0:4222"), stan.SetConnectionLostHandler(func(c stan.Conn, _ error) {
        go func() {
            for {
                // Reconnect if the connection is lost.
                if stanConnection == nil || stanConnection.NatsConn() == nil ||  !stanConnection.NatsConn().IsConnected() {
                    stanConnection, _ = stan.Connect("test-cluster", "test-client", stan.NatsURL("nats://yourusername:yoursecret@0.0.0.0:4222"), stan.SetConnectionLostHandler(func(c stan.Conn, _ error) {
                        if c.NatsConn() != nil {
                            c.NatsConn().Close()
                        }
                        _ = c.Close()
                    }))
                    if stanConnection != nil {
                        subscribe()
                    }

                }
            }

        }()
    }))

    // Subscribe to subject
    subscribe()

    // Keep the connection alive
    runtime.Goexit()
}

go run nats.go
2017/07/07 11:47:40 Connected
2017/07/07 11:47:40 Subscribing to subject 'bucketevents'

Open another terminal and upload a JPEG image into images bucket.

mc cp myphoto.jpg myminio/images

The example nats.go program prints event notification to console.

Received a message: {"EventType":"s3:ObjectCreated:Put","Key":"images/myphoto.jpg","Records":[{"eventVersion":"2.0","eventSource":"minio:s3","awsRegion":"","eventTime":"2017-07-07T18:46:37Z","eventName":"s3:ObjectCreated:Put","userIdentity":{"principalId":"minio"},"requestParameters":{"sourceIPAddress":"192.168.1.80:55328"},"responseElements":{"x-amz-request-id":"14CF20BD1EFD5B93","x-minio-origin-endpoint":"http://127.0.0.1:9000"},"s3":{"s3SchemaVersion":"1.0","configurationId":"Config","bucket":{"name":"images","ownerIdentity":{"principalId":"minio"},"arn":"arn:aws:s3:::images"},"object":{"key":"myphoto.jpg","size":248682,"eTag":"f1671feacb8bbf7b0397c6e9364e8c92","contentType":"image/jpeg","userDefined":{"content-type":"image/jpeg"},"versionId":"1","sequencer":"14CF20BD1EFD5B93"}},"source":{"host":"192.168.1.80","port":"55328","userAgent":"MinIO (linux; amd64) minio-go/2.0.4 mc/DEVELOPMENT.GOGET"}}],"level":"info","msg":"","time":"2017-07-07T11:46:37-07:00"}

Publish MinIO events via PostgreSQL

NOTE: Until release RELEASE.2020-04-10T03-34-42Z PostgreSQL notification used to support following options:

host                (hostname)           Postgres server hostname (used only if `connection_string` is empty)
port                (port)               Postgres server port, defaults to `5432` (used only if `connection_string` is empty)
username            (string)             database username (used only if `connection_string` is empty)
password            (string)             database password (used only if `connection_string` is empty)
database            (string)             database name (used only if `connection_string` is empty)

These are now deprecated, if you plan to upgrade to any releases after RELEASE.2020-04-10T03-34-42Z make sure
to migrate to only using connection_string option. To migrate, once you have upgraded all the servers use the
following command to update the existing notification targets.

mc admin config set myminio/ notify_postgres[:name] connection_string="host=hostname port=2832 username=psqluser password=psqlpass database=bucketevents"

Please make sure this step is carried out, without this step PostgreSQL notification targets will not work,
an error message will be shown on the console upon server upgrade/restart, make sure to follow the above
instructions appropriately. For further questions please join our https://slack.min.io

Install PostgreSQL database server. For illustrative purposes, we have set the "postgres" user password as password and created a database called minio_events to store the events.

This notification target supports two formats: namespace and access.

When the namespace format is used, MinIO synchronizes objects in the bucket with rows in the table. It creates rows with two columns: key and value. The key is the bucket and object name of an object that exists in MinIO. The value is JSON encoded event data about the operation that created/replaced the object in MinIO. When objects are updated or deleted, the corresponding row from this table is updated or deleted respectively.

When the access format is used, MinIO appends events to a table. It creates rows with two columns: event_time and event_data. The event_time is the time at which the event occurred in the MinIO server. The event_data is the JSON encoded event data about the operation on an object. No rows are deleted or modified in this format.

The steps below show how to use this notification target in namespace format. The other format is very similar and is omitted for brevity.

Step 1: Ensure minimum requirements are met

MinIO requires PostgreSQL version 9.5 or above. MinIO uses the INSERT ON CONFLICT (aka UPSERT) feature, introduced in version 9.5 and the JSONB data-type introduced in version 9.4.

Step 2: Add PostgreSQL endpoint to MinIO

The PostgreSQL configuration is located in the notify_postgresql key. Create a configuration key-value pair here for your PostgreSQL instance. The key is a name for your PostgreSQL endpoint, and the value is a collection of key-value parameters described in the table below.

KEY:
notify_postgres[:name]  publish bucket notifications to Postgres databases

ARGS:
connection_string*  (string)             Postgres server connection-string e.g. "host=localhost port=5432 dbname=minio_events user=postgres password=password sslmode=disable"
table*              (string)             DB table name to store/update events, table is auto-created
format*             (namespace*|access)  'namespace' reflects current bucket/object list and 'access' reflects a journal of object operations, defaults to 'namespace'
queue_dir           (path)               staging dir for undelivered messages e.g. '/home/events'
queue_limit         (number)             maximum limit for undelivered messages, defaults to '100000'
comment             (sentence)           optionally add a comment to this setting

or environment variables

KEY:
notify_postgres[:name]  publish bucket notifications to Postgres databases

ARGS:
MINIO_NOTIFY_POSTGRES_ENABLE*             (on|off)             enable notify_postgres target, default is 'off'
MINIO_NOTIFY_POSTGRES_CONNECTION_STRING*  (string)             Postgres server connection-string e.g. "host=localhost port=5432 dbname=minio_events user=postgres password=password sslmode=disable"
MINIO_NOTIFY_POSTGRES_TABLE*              (string)             DB table name to store/update events, table is auto-created
MINIO_NOTIFY_POSTGRES_FORMAT*             (namespace*|access)  'namespace' reflects current bucket/object list and 'access' reflects a journal of object operations, defaults to 'namespace'
MINIO_NOTIFY_POSTGRES_QUEUE_DIR           (path)               staging dir for undelivered messages e.g. '/home/events'
MINIO_NOTIFY_POSTGRES_QUEUE_LIMIT         (number)             maximum limit for undelivered messages, defaults to '100000'
MINIO_NOTIFY_POSTGRES_COMMENT             (sentence)           optionally add a comment to this setting

MinIO supports persistent event store. The persistent store will backup events when the PostgreSQL connection goes offline and replays it when the broker comes back online. The event store can be configured by setting the directory path in queue_dir field and the maximum limit of events in the queue_dir in queue_limit field. For eg, the queue_dir can be /home/events and queue_limit can be 1000. By default, the queue_limit is set to 100000.

Note that for illustration here, we have disabled SSL. In the interest of security, for production this is not recommended.
To update the configuration, use mc admin config get command to get the current configuration.

$ mc admin config get myminio notify_postgres
notify_postgres:1 queue_dir="" connection_string="" queue_limit="0"  table="" format="namespace"

Use mc admin config set command to update the configuration for the deployment. Restart the MinIO server to put the changes into effect. The server will print a line like SQS ARNs: arn:minio:sqs::1:postgresql at start-up if there were no errors.

$ mc admin config set myminio notify_postgres:1 connection_string="host=localhost port=5432 dbname=minio_events user=postgres password=password sslmode=disable" table="bucketevents" format="namespace"

Note that, you can add as many PostgreSQL server endpoint configurations as needed by providing an identifier (like "1" in the example above) for the PostgreSQL instance and an object of per-server configuration parameters.

Step 3: Enable bucket notification using MinIO client

We will now enable bucket event notifications on a bucket named images. Whenever a JPEG image is created/overwritten, a new row is added or an existing row is updated in the PostgreSQL configured above. When an existing object is deleted, the corresponding row is deleted from the PostgreSQL table. Thus, the rows in the PostgreSQL table, reflect the .jpg objects in the images bucket.

To configure this bucket notification, we need the ARN printed by MinIO in the previous step. Additional information about ARN is available here.

With the mc tool, the configuration is very simple to add. Let us say that the MinIO server is aliased as myminio in our mc configuration. Execute the following:

# Create bucket named `images` in myminio
mc mb myminio/images
# Add notification configuration on the `images` bucket using the MySQL ARN. The --suffix argument filters events.
mc event add myminio/images arn:minio:sqs::1:postgresql --suffix .jpg
# Print out the notification configuration on the `images` bucket.
mc event list myminio/images
mc event list myminio/images
arn:minio:sqs::1:postgresql s3:ObjectCreated:*,s3:ObjectRemoved:* Filter: suffix=”.jpg”

Step 4: Test on PostgreSQL

Open another terminal and upload a JPEG image into images bucket.

mc cp myphoto.jpg myminio/images

Open PostgreSQL terminal to list the rows in the bucketevents table.

$ psql -h 127.0.0.1 -U postgres -d minio_events
minio_events=# select * from bucketevents;

key                 |                      value
--------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 images/myphoto.jpg | {"Records": [{"s3": {"bucket": {"arn": "arn:aws:s3:::images", "name": "images", "ownerIdentity": {"principalId": "minio"}}, "object": {"key": "myphoto.jpg", "eTag": "1d97bf45ecb37f7a7b699418070df08f", "size": 56060, "sequencer": "147CE57C70B31931"}, "configurationId": "Config", "s3SchemaVersion": "1.0"}, "awsRegion": "", "eventName": "s3:ObjectCreated:Put", "eventTime": "2016-10-12T21:18:20Z", "eventSource": "aws:s3", "eventVersion": "2.0", "userIdentity": {"principalId": "minio"}, "responseElements": {}, "requestParameters": {"sourceIPAddress": "[::1]:39706"}}]}
(1 row)

Publish MinIO events via MySQL

NOTE: Until release RELEASE.2020-04-10T03-34-42Z MySQL notification used to support following options:

host         (hostname)           MySQL server hostname (used only if `dsn_string` is empty)
port         (port)               MySQL server port (used only if `dsn_string` is empty)
username     (string)             database username (used only if `dsn_string` is empty)
password     (string)             database password (used only if `dsn_string` is empty)
database     (string)             database name (used only if `dsn_string` is empty)

These are now deprecated, if you plan to upgrade to any releases after RELEASE.2020-04-10T03-34-42Z make sure
to migrate to only using dsn_string option. To migrate, once you have upgraded all the servers use the
following command to update the existing notification targets.

mc admin config set myminio/ notify_mysql[:name] dsn_string="mysqluser:mysqlpass@tcp(localhost:2832)/bucketevents"

Please make sure this step is carried out, without this step MySQL notification targets will not work,
an error message will be shown on the console upon server upgrade/restart, make sure to follow the above
instructions appropriately. For further questions please join our https://slack.min.io

Install MySQL from here. For illustrative purposes, we have set the root password as password and created a database called miniodb to store the events.

This notification target supports two formats: namespace and access.

When the namespace format is used, MinIO synchronizes objects in the bucket with rows in the table. It creates rows with two columns: key_name and value. The key_name is the bucket and object name of an object that exists in MinIO. The value is JSON encoded event data about the operation that created/replaced the object in MinIO. When objects are updated or deleted, the corresponding row from this table is updated or deleted respectively.

When the access format is used, MinIO appends events to a table. It creates rows with two columns: event_time and event_data. The event_time is the time at which the event occurred in the MinIO server. The event_data is the JSON encoded event data about the operation on an object. No rows are deleted or modified in this format.

The steps below show how to use this notification target in namespace format. The other format is very similar and is omitted for brevity.

Step 1: Ensure minimum requirements are met

MinIO requires MySQL version 5.7.8 or above. MinIO uses the JSON data-type introduced in version 5.7.8. We tested this setup on MySQL 5.7.17.

Step 2: Add MySQL server endpoint configuration to MinIO

The MySQL configuration is located in the notify_mysql key. Create a configuration key-value pair here for your MySQL instance. The key is a name for your MySQL endpoint, and the value is a collection of key-value parameters described in the table below.

KEY:
notify_mysql[:name]  publish bucket notifications to MySQL databases. When multiple MySQL server endpoints are needed, a user specified "name" can be added for each configuration, (e.g."notify_mysql:myinstance").

ARGS:
dsn_string*  (string)             MySQL data-source-name connection string e.g. "<user>:<password>@tcp(<host>:<port>)/<database>"
table*       (string)             DB table name to store/update events, table is auto-created
format*      (namespace*|access)  'namespace' reflects current bucket/object list and 'access' reflects a journal of object operations, defaults to 'namespace'
queue_dir    (path)               staging dir for undelivered messages e.g. '/home/events'
queue_limit  (number)             maximum limit for undelivered messages, defaults to '100000'
comment      (sentence)           optionally add a comment to this setting

or environment variables

KEY:
notify_mysql[:name]  publish bucket notifications to MySQL databases

ARGS:
MINIO_NOTIFY_MYSQL_ENABLE*      (on|off)             enable notify_mysql target, default is 'off'
MINIO_NOTIFY_MYSQL_DSN_STRING*  (string)             MySQL data-source-name connection string e.g. "<user>:<password>@tcp(<host>:<port>)/<database>"
MINIO_NOTIFY_MYSQL_TABLE*       (string)             DB table name to store/update events, table is auto-created
MINIO_NOTIFY_MYSQL_FORMAT*      (namespace*|access)  'namespace' reflects current bucket/object list and 'access' reflects a journal of object operations, defaults to 'namespace'
MINIO_NOTIFY_MYSQL_QUEUE_DIR    (path)               staging dir for undelivered messages e.g. '/home/events'
MINIO_NOTIFY_MYSQL_QUEUE_LIMIT  (number)             maximum limit for undelivered messages, defaults to '100000'
MINIO_NOTIFY_MYSQL_COMMENT      (sentence)           optionally add a comment to this setting

dsn_string is required and is of form "<user>:<password>@tcp(<host>:<port>)/<database>"

MinIO supports persistent event store. The persistent store will backup events if MySQL connection goes offline and then replays the stored events when the broken connection comes back up. The event store can be configured by setting a directory path in queue_dir field, and the maximum number of events, which can be stored in a queue_dir, in queue_limit field. For example, queue_dir can be set to /home/events and queue_limit can be set to 1000. By default, the queue_limit is set to 100000.

Before updating the configuration, let's start with mc admin config get command to get the current configuration.

$ mc admin config get myminio/ notify_mysql
notify_mysql:myinstance enable=off format=namespace host= port= username= password= database= dsn_string= table= queue_dir= queue_limit=0

Use mc admin config set command to update MySQL notification configuration for the deployment with dsn_string parameter:

$ mc admin config set myminio notify_mysql:myinstance table="minio_images" dsn_string="root:xxxx@tcp(172.17.0.1:3306)/miniodb"

Note that, you can add as many MySQL server endpoint configurations as needed by providing an identifier (like "myinstance" in the example above) for each MySQL instance desired.

Restart the MinIO server to put the changes into effect. The server will print a line like SQS ARNs: arn:minio:sqs::myinstance:mysql at start-up, if there are no errors.

Step 3: Enable bucket notification using MinIO client

We will now setup bucket notifications on a bucket named images. Whenever a JPEG image object is created/overwritten, a new row is added or an existing row is updated in the MySQL table configured above. When an existing object is deleted, the corresponding row is deleted from the MySQL table. Thus, the rows in the MySQL table, reflect the .jpg objects in the images bucket.

To configure this bucket notification, we need the ARN printed by MinIO in the previous step. Additional information about ARN is available here.

With the mc tool, the configuration is very simple to add. Let us say that the MinIO server is aliased as myminio in our mc configuration. Execute the following:

# Create bucket named `images` in myminio
mc mb myminio/images
# Add notification configuration on the `images` bucket using the MySQL ARN. The --suffix argument filters events.
mc event add myminio/images arn:minio:sqs::myinstance:mysql --suffix .jpg
# Print out the notification configuration on the `images` bucket.
mc event list myminio/images
arn:minio:sqs::myinstance:mysql s3:ObjectCreated:*,s3:ObjectRemoved:*,s3:ObjectAccessed:* Filter: suffix=”.jpg”

Step 4: Test on MySQL

Open another terminal and upload a JPEG image into images bucket:

mc cp myphoto.jpg myminio/images

Open MySQL terminal and list the rows in the minio_images table.

$ mysql -h 172.17.0.1 -P 3306 -u root -p miniodb
mysql> select * from minio_images;
+--------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| key_name           | value                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
+--------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| images/myphoto.jpg | {"Records": [{"s3": {"bucket": {"arn": "arn:aws:s3:::images", "name": "images", "ownerIdentity": {"principalId": "minio"}}, "object": {"key": "myphoto.jpg", "eTag": "467886be95c8ecfd71a2900e3f461b4f", "size": 26, "sequencer": "14AC59476F809FD3"}, "configurationId": "Config", "s3SchemaVersion": "1.0"}, "awsRegion": "", "eventName": "s3:ObjectCreated:Put", "eventTime": "2017-03-16T11:29:00Z", "eventSource": "aws:s3", "eventVersion": "2.0", "userIdentity": {"principalId": "minio"}, "responseElements": {"x-amz-request-id": "14AC59476F809FD3", "x-minio-origin-endpoint": "http://192.168.86.110:9000"}, "requestParameters": {"sourceIPAddress": "127.0.0.1:38260"}}]} |
+--------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)

Publish MinIO events via Kafka

Install Apache Kafka from here.

Step 1: Ensure minimum requirements are met

MinIO requires Kafka version 0.10 or 0.9. Internally MinIO uses the Shopify/sarama library and so has the same version compatibility as provided by this library.

Step 2: Add Kafka endpoint to MinIO

MinIO supports persistent event store. The persistent store will backup events when the kafka broker goes offline and replays it when the broker comes back online. The event store can be configured by setting the directory path in queue_dir field and the maximum limit of events in the queue_dir in queue_limit field. For eg, the queue_dir can be /home/events and queue_limit can be 1000. By default, the queue_limit is set to 100000.

KEY:
notify_kafka[:name]  publish bucket notifications to Kafka endpoints

ARGS:
brokers*         (csv)       comma separated list of Kafka broker addresses
topic            (string)    Kafka topic used for bucket notifications
sasl_username    (string)    username for SASL/PLAIN or SASL/SCRAM authentication
sasl_password    (string)    password for SASL/PLAIN or SASL/SCRAM authentication
sasl_mechanism   (string)    sasl authentication mechanism, default 'PLAIN'
tls_client_auth  (string)    clientAuth determines the Kafka server's policy for TLS client auth
sasl             (on|off)    set to 'on' to enable SASL authentication
tls              (on|off)    set to 'on' to enable TLS
tls_skip_verify  (on|off)    trust server TLS without verification, defaults to "on" (verify)
client_tls_cert  (path)      path to client certificate for mTLS auth
client_tls_key   (path)      path to client key for mTLS auth
queue_dir        (path)      staging dir for undelivered messages e.g. '/home/events'
queue_limit      (number)    maximum limit for undelivered messages, defaults to '100000'
version          (string)    specify the version of the Kafka cluster e.g '2.2.0'
comment          (sentence)  optionally add a comment to this setting

or environment variables

KEY:
notify_kafka[:name]  publish bucket notifications to Kafka endpoints

ARGS:
MINIO_NOTIFY_KAFKA_ENABLE*          (on|off)                enable notify_kafka target, default is 'off'
MINIO_NOTIFY_KAFKA_BROKERS*         (csv)                   comma separated list of Kafka broker addresses
MINIO_NOTIFY_KAFKA_TOPIC            (string)                Kafka topic used for bucket notifications
MINIO_NOTIFY_KAFKA_SASL_USERNAME    (string)                username for SASL/PLAIN or SASL/SCRAM authentication
MINIO_NOTIFY_KAFKA_SASL_PASSWORD    (string)                password for SASL/PLAIN or SASL/SCRAM authentication
MINIO_NOTIFY_KAFKA_SASL_MECHANISM   (plain*|sha256|sha512)  sasl authentication mechanism, default 'plain'
MINIO_NOTIFY_KAFKA_TLS_CLIENT_AUTH  (string)                clientAuth determines the Kafka server's policy for TLS client auth
MINIO_NOTIFY_KAFKA_SASL             (on|off)                set to 'on' to enable SASL authentication
MINIO_NOTIFY_KAFKA_TLS              (on|off)                set to 'on' to enable TLS
MINIO_NOTIFY_KAFKA_TLS_SKIP_VERIFY  (on|off)                trust server TLS without verification, defaults to "on" (verify)
MINIO_NOTIFY_KAFKA_CLIENT_TLS_CERT  (path)                  path to client certificate for mTLS auth
MINIO_NOTIFY_KAFKA_CLIENT_TLS_KEY   (path)                  path to client key for mTLS auth
MINIO_NOTIFY_KAFKA_QUEUE_DIR        (path)                  staging dir for undelivered messages e.g. '/home/events'
MINIO_NOTIFY_KAFKA_QUEUE_LIMIT      (number)                maximum limit for undelivered messages, defaults to '100000'
MINIO_NOTIFY_KAFKA_COMMENT          (sentence)              optionally add a comment to this setting
MINIO_NOTIFY_KAFKA_VERSION          (string)                specify the version of the Kafka cluster e.g. '2.2.0'

To update the configuration, use mc admin config get command to get the current configuration.

$ mc admin config get myminio/ notify_kafka
notify_kafka:1 tls_skip_verify="off"  queue_dir="" queue_limit="0" sasl="off" sasl_password="" sasl_username="" tls_client_auth="0" tls="off" brokers="" topic="" client_tls_cert="" client_tls_key="" version=""

Use mc admin config set command to update the configuration for the deployment. Restart the MinIO server to put the changes into effect. The server will print a line like SQS ARNs: arn:minio:sqs::1:kafka at start-up if there were no errors.bucketevents is the topic used by kafka in this example.

$ mc admin config set myminio notify_kafka:1 tls_skip_verify="off"  queue_dir="" queue_limit="0" sasl="off" sasl_password="" sasl_username="" tls_client_auth="0" tls="off" client_tls_cert="" client_tls_key="" brokers="localhost:9092,localhost:9093" topic="bucketevents" version=""

Step 3: Enable bucket notification using MinIO client

We will enable bucket event notification to trigger whenever a JPEG image is uploaded or deleted from images bucket on myminio server. Here ARN value is arn:minio:sqs::1:kafka. To understand more about ARN please follow AWS ARN documentation.

mc mb myminio/images
mc event add  myminio/images arn:minio:sqs::1:kafka --suffix .jpg
mc event list myminio/images
arn:minio:sqs::1:kafka s3:ObjectCreated:*,s3:ObjectRemoved:* Filter: suffix=”.jpg”

Step 4: Test on Kafka

We used kafkacat to print all notifications on the console.

kafkacat -C -b localhost:9092 -t bucketevents

Open another terminal and upload a JPEG image into images bucket.

mc cp myphoto.jpg myminio/images

kafkacat prints the event notification to the console.

kafkacat -b localhost:9092 -t bucketevents
{
    "EventName": "s3:ObjectCreated:Put",
    "Key": "images/myphoto.jpg",
    "Records": [
        {
            "eventVersion": "2.0",
            "eventSource": "minio:s3",
            "awsRegion": "",
            "eventTime": "2019-09-10T17:41:54Z",
            "eventName": "s3:ObjectCreated:Put",
            "userIdentity": {
                "principalId": "AKIAIOSFODNN7EXAMPLE"
            },
            "requestParameters": {
                "accessKey": "AKIAIOSFODNN7EXAMPLE",
                "region": "",
                "sourceIPAddress": "192.168.56.192"
            },
            "responseElements": {
                "x-amz-request-id": "15C3249451E12784",
                "x-minio-deployment-id": "751a8ba6-acb2-42f6-a297-4cdf1cf1fa4f",
                "x-minio-origin-endpoint": "http://192.168.97.83:9000"
            },
            "s3": {
                "s3SchemaVersion": "1.0",
                "configurationId": "Config",
                "bucket": {
                    "name": "images",
                    "ownerIdentity": {
                        "principalId": "AKIAIOSFODNN7EXAMPLE"
                    },
                    "arn": "arn:aws:s3:::images"
                },
                "object": {
                    "key": "myphoto.jpg",
                    "size": 6474,
                    "eTag": "430f89010c77aa34fc8760696da62d08-1",
                    "contentType": "image/jpeg",
                    "userMetadata": {
                        "content-type": "image/jpeg"
                    },
                    "versionId": "1",
                    "sequencer": "15C32494527B46C5"
                }
            },
            "source": {
                "host": "192.168.56.192",
                "port": "",
                "userAgent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:69.0) Gecko/20100101 Firefox/69.0"
            }
        }
    ]
}

Publish MinIO events via Webhooks

Webhooks are a way to receive information when it happens, rather than continually polling for that data.

Step 1: Add Webhook endpoint to MinIO

MinIO supports persistent event store. The persistent store will backup events when the webhook goes offline and replays it when the broker comes back online. The event store can be configured by setting the directory path in queue_dir field and the maximum limit of events in the queue_dir in queue_limit field. For eg, the queue_dir can be /home/events and queue_limit can be 1000. By default, the queue_limit is set to 100000.

KEY:
notify_webhook[:name]  publish bucket notifications to webhook endpoints

ARGS:
endpoint*    (url)       webhook server endpoint e.g. http://localhost:8080/minio/events
auth_token   (string)    opaque string or JWT authorization token
queue_dir    (path)      staging dir for undelivered messages e.g. '/home/events'
queue_limit  (number)    maximum limit for undelivered messages, defaults to '100000'
client_cert  (string)    client cert for Webhook mTLS auth
client_key   (string)    client cert key for Webhook mTLS auth
comment      (sentence)  optionally add a comment to this setting

or environment variables

KEY:
notify_webhook[:name]  publish bucket notifications to webhook endpoints

ARGS:
MINIO_NOTIFY_WEBHOOK_ENABLE*      (on|off)    enable notify_webhook target, default is 'off'
MINIO_NOTIFY_WEBHOOK_ENDPOINT*    (url)       webhook server endpoint e.g. http://localhost:8080/minio/events
MINIO_NOTIFY_WEBHOOK_AUTH_TOKEN   (string)    opaque string or JWT authorization token
MINIO_NOTIFY_WEBHOOK_QUEUE_DIR    (path)      staging dir for undelivered messages e.g. '/home/events'
MINIO_NOTIFY_WEBHOOK_QUEUE_LIMIT  (number)    maximum limit for undelivered messages, defaults to '100000'
MINIO_NOTIFY_WEBHOOK_COMMENT      (sentence)  optionally add a comment to this setting
MINIO_NOTIFY_WEBHOOK_CLIENT_CERT  (string)    client cert for Webhook mTLS auth
MINIO_NOTIFY_WEBHOOK_CLIENT_KEY   (string)    client cert key for Webhook mTLS auth   
$ mc admin config get myminio/ notify_webhook
notify_webhook:1 endpoint="" auth_token="" queue_limit="0" queue_dir="" client_cert="" client_key=""

Use mc admin config set command to update the configuration for the deployment. Here the endpoint is the server listening for webhook notifications. Save the settings and restart the MinIO server for changes to take effect. Note that the endpoint needs to be live and reachable when you restart your MinIO server.

$ mc admin config set myminio notify_webhook:1 queue_limit="0"  endpoint="http://localhost:3000" queue_dir=""

Step 2: Enable bucket notification using MinIO client

We will enable bucket event notification to trigger whenever a JPEG image is uploaded to images bucket on myminio server. Here ARN value is arn:minio:sqs::1:webhook. To learn more about ARN please follow AWS ARN documentation.

mc mb myminio/images
mc mb myminio/images-thumbnail
mc event add myminio/images arn:minio:sqs::1:webhook --event put --suffix .jpg

Check if event notification is successfully configured by

mc event list myminio/images

You should get a response like this

arn:minio:sqs::1:webhook   s3:ObjectCreated:*   Filter: suffix=".jpg"

Step 3: Test with Thumbnailer

We used Thumbnailer to listen for MinIO notifications when a new JPEG file is uploaded (HTTP PUT). Triggered by a notification, Thumbnailer uploads a thumbnail of new image to MinIO server. To start with, download and install Thumbnailer.

git clone https://github.com/minio/thumbnailer/
npm install

Then open the Thumbnailer config file at config/webhook.json and add the configuration for your MinIO server and then start Thumbnailer by

NODE_ENV=webhook node thumbnail-webhook.js

Thumbnailer starts running at http://localhost:3000/. Next, configure the MinIO server to send notifications to this URL (as mentioned in step 1) and use mc to set up bucket notifications (as mentioned in step 2). Then upload a JPEG image to MinIO server by

mc cp ~/images.jpg myminio/images
.../images.jpg:  8.31 KB / 8.31 KB ┃▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓┃ 100.00% 59.42 KB/s 0s

Wait a few moments, then check the bucket’s contents with mc ls — you will see a thumbnail appear.

mc ls myminio/images-thumbnail
[2017-02-08 11:39:40 IST]   992B images-thumbnail.jpg

Publish MinIO events to NSQ

Install an NSQ Daemon from here. Or use the following Docker
command for starting an nsq daemon:

docker run --rm -p 4150-4151:4150-4151 nsqio/nsq /nsqd

Step 1: Add NSQ endpoint to MinIO

MinIO supports persistent event store. The persistent store will backup events when the NSQ broker goes offline and replays it when the broker comes back online. The event store can be configured by setting the directory path in queue_dir field and the maximum limit of events in the queue_dir in queue_limit field. For eg, the queue_dir can be /home/events and queue_limit can be 1000. By default, the queue_limit is set to 100000.

To update the configuration, use mc admin config get command to get the current configuration for notify_nsq.

KEY:
notify_nsq[:name]  publish bucket notifications to NSQ endpoints

ARGS:
nsqd_address*    (address)   NSQ server address e.g. '127.0.0.1:4150'
topic*           (string)    NSQ topic
tls              (on|off)    set to 'on' to enable TLS
tls_skip_verify  (on|off)    trust server TLS without verification, defaults to "on" (verify)
queue_dir        (path)      staging dir for undelivered messages e.g. '/home/events'
queue_limit      (number)    maximum limit for undelivered messages, defaults to '100000'
comment          (sentence)  optionally add a comment to this setting

or environment variables

KEY:
notify_nsq[:name]  publish bucket notifications to NSQ endpoints

ARGS:
MINIO_NOTIFY_NSQ_ENABLE*          (on|off)    enable notify_nsq target, default is 'off'
MINIO_NOTIFY_NSQ_NSQD_ADDRESS*    (address)   NSQ server address e.g. '127.0.0.1:4150'
MINIO_NOTIFY_NSQ_TOPIC*           (string)    NSQ topic
MINIO_NOTIFY_NSQ_TLS              (on|off)    set to 'on' to enable TLS
MINIO_NOTIFY_NSQ_TLS_SKIP_VERIFY  (on|off)    trust server TLS without verification, defaults to "on" (verify)
MINIO_NOTIFY_NSQ_QUEUE_DIR        (path)      staging dir for undelivered messages e.g. '/home/events'
MINIO_NOTIFY_NSQ_QUEUE_LIMIT      (number)    maximum limit for undelivered messages, defaults to '100000'
MINIO_NOTIFY_NSQ_COMMENT          (sentence)  optionally add a comment to this setting
$ mc admin config get myminio/ notify_nsq
notify_nsq:1 nsqd_address="" queue_dir="" queue_limit="0"  tls_enable="off" tls_skip_verify="off" topic=""

Use mc admin config set command to update the configuration for the deployment. Restart the MinIO server to put the changes into effect. The server will print a line like SQS ARNs: arn:minio:sqs::1:nsq at start-up if there were no errors.

$ mc admin config set myminio notify_nsq:1 nsqd_address="127.0.0.1:4150" queue_dir="" queue_limit="0" tls_enable="off" tls_skip_verify="on" topic="minio"

Note that, you can add as many NSQ daemon endpoint configurations as needed by providing an identifier (like "1" in the example above) for the NSQ instance and an object of per-server configuration parameters.

Step 2: Enable bucket notification using MinIO client

We will enable bucket event notification to trigger whenever a JPEG image is uploaded or deleted images bucket on myminio server. Here ARN value is arn:minio:sqs::1:nsq.

mc mb myminio/images
mc event add  myminio/images arn:minio:sqs::1:nsq --suffix .jpg
mc event list myminio/images
arn:minio:sqs::1:nsq s3:ObjectCreated:*,s3:ObjectRemoved:* Filter: suffix=”.jpg”

Step 3: Test on NSQ

The simplest test is to download nsq_tail from nsq github

./nsq_tail -nsqd-tcp-address 127.0.0.1:4150 -topic minio

Open another terminal and upload a JPEG image into images bucket.

mc cp gopher.jpg myminio/images

You should receive the following event notification via NSQ once the upload completes.

{"EventName":"s3:ObjectCreated:Put","Key":"images/gopher.jpg","Records":[{"eventVersion":"2.0","eventSource":"minio:s3","awsRegion":"","eventTime":"2018-10-31T09:31:11Z","eventName":"s3:ObjectCreated:Put","userIdentity":{"principalId":"21EJ9HYV110O8NVX2VMS"},"requestParameters":{"sourceIPAddress":"10.1.1.1"},"responseElements":{"x-amz-request-id":"1562A792DAA53426","x-minio-origin-endpoint":"http://10.0.3.1:9000"},"s3":{"s3SchemaVersion":"1.0","configurationId":"Config","bucket":{"name":"images","ownerIdentity":{"principalId":"21EJ9HYV110O8NVX2VMS"},"arn":"arn:aws:s3:::images"},"object":{"key":"gopher.jpg","size":162023,"eTag":"5337769ffa594e742408ad3f30713cd7","contentType":"image/jpeg","userMetadata":{"content-type":"image/jpeg"},"versionId":"1","sequencer":"1562A792DAA53426"}},"source":{"host":"","port":"","userAgent":"MinIO (linux; amd64) minio-go/v6.0.8 mc/DEVELOPMENT.GOGET"}}]}