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Publish Events to NATS

MinIO supports publishing bucket notification events to a NATS service endpoint.

Add a NATS Endpoint to a MinIO Deployment

The following procedure adds a new NATS service endpoint for supporting bucket notifications in a MinIO deployment.

Important

This procedure requires restarting all minio server processes associated to the deployment at the same time. There is typically a brief period of time during which API operations are interrupted or may fail.

Applications using an S3-compatible SDK with built-in retry logic or which implement manual retry logic typically experience no notable interruption in services. For applications which cannot use retry-logic, consider scheduling a maintenance period to minimize interruption of services while performing this procedure.

Prerequisites

MinIO mc Command Line Tool

This procedure uses the mc command line tool for certain actions. See the mc Quickstart for installation instructions.

1) Add the NATS Endpoint to MinIO

You can configure a new NATS service endpoint using either environment variables or by setting runtime configuration settings.

MinIO supports specifying the NATS service endpoint and associated configuration settings using environment variables. The minio server process applies the specified settings on its next startup.

The following example code sets all environment variables related to configuring an NATS service endpoint. The minimum required variables are MINIO_NOTIFY_NATS_ADDRESS and MINIO_NOTIFY_NATS_SUBJECT:

set MINIO_NOTIFY_NATS_ENABLE_<IDENTIFIER>="on"
set MINIO_NOTIFY_NATS_ADDRESS_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_SUBJECT_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_USERNAME_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_PASSWORD_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_TOKEN_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_TLS_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_TLS_SKIP_VERIFY_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_PING_INTERVAL_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_STREAMING_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_STREAMING_ASYNC_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_STREAMING_MAX_PUB_ACKS_IN_FLIGHT_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_STREAMING_CLUSTER_ID_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_CERT_AUTHORITY_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_CLIENT_CERT_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_CLIENT_KEY_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_QUEUE_DIR_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_QUEUE_LIMIT_<IDENTIFIER>="<string>"
set MINIO_NOTIFY_NATS_COMMENT_<IDENTIFIER>="<string>"
  • Replace <IDENTIFIER> with a unique descriptive string for the NATS service endpoint. Use the same <IDENTIFIER> value for all environment variables related to the new target service endpoint. The following examples assume an identifier of PRIMARY.

    If the specified <IDENTIFIER> matches an existing NATS service endpoint on the MinIO deployment, the new settings override any existing settings for that endpoint. Use mc admin config get notify_nats to review the currently configured NATS endpoints on the MinIO deployment.

  • Replace <ENDPOINT> with the URL of the NATS service endpoint. For example: htpps://nats-endpoint.example.com:4222

See NATS Service for Bucket Notifications for complete documentation on each environment variable.

MinIO supports adding or updating NATS endpoints on a running minio server process using the mc admin config set command and the notify_nats configuration key. You must restart the minio server process to apply any new or updated configuration settings.

The following example code sets all settings related to configuring an NATS service endpoint. The minimum required setting are notify_nats address and notify_nats subject:

mc admin config set ALIAS/ notify_nats:IDENTIFIER \
   address="HOSTNAME" \
   subject="<string>" \
   username="<string>" \
   password="<string>" \
   token="<string>" \
   tls="<string>" \
   tls_skip_verify="<string>" \
   ping_interval="<string>" \
   streaming="<string>" \
   streaming_async="<string>" \
   streaming_max_pub_acks_in_flight="<string>" \
   streaming_cluster_id="<string>" \
   cert_authority="<string>" \
   client_cert="<string>" \
   client_key="<string>" \
   queue_dir="<string>" \
   queue_limit="<string>" \
   comment="<string>"
  • Replace IDENTIFIER with a unique descriptive string for the NATS service endpoint. The following examples in this procedure assume an identifier of PRIMARY.

    If the specified IDENTIFIER matches an existing NATS service endpoint on the MinIO deployment, the new settings override any existing settings for that endpoint. Use mc admin config get notify_nats to review the currently configured NATS endpoints on the MinIO deployment.

  • Replace ENDPOINT with the URL of the NATS service endpoint. For example: htpps://nats-endpoint.example.com:4222.

See NATS Bucket Notification Configuration Settings for complete documentation on each setting.

2) Restart the MinIO Deployment

You must restart the MinIO deployment to apply the configuration changes. Use the mc admin service restart command to restart the deployment.

Important

MinIO restarts all minio server processes associated to the deployment at the same time. Applications may experience a brief period of downtime during the restart process.

Consider scheduling the restart during a maintenance period to minimize interruption of services.

mc admin service restart ALIAS

Replace ALIAS with the alias of the deployment to restart.

The minio server process prints a line on startup for each configured NATS target similar to the following:

SQS ARNs: arn:minio:sqs::primary:nats

You must specify the ARN resource when configuring bucket notifications with the associated NATS deployment as a target.

3) Configure Bucket Notifications using the NATS Endpoint as a Target

Use the mc event add command to add a new bucket notification event with the configured NATS service as a target:

mc event add ALIAS/BUCKET arn:minio:sqs::primary:nats \
  --event EVENTS
  • Replace ALIAS with the alias of a MinIO deployment.

  • Replace BUCKET with the name of the bucket in which to configure the event.

  • Replace EVENTS with a comma-separated list of events for which MinIO triggers notifications.

Use mc event list to view all configured bucket events for a given notification target:

mc event list ALIAS/BUCKET arn:minio:sqs::primary:nats

4) Validate the Configured Events

Perform an action on the bucket for which you configured the new event and check the NATS service for the notification data. The action required depends on which events were specified when configuring the bucket notification.

For example, if the bucket notification configuration includes the s3:ObjectCreated:Put event, you can use the mc cp command to create a new object in the bucket and trigger a notification.

mc cp ~/data/new-object.txt ALIAS/BUCKET

Update an NATS Endpoint in a MinIO Deployment

The following procedure updates an existing NATS service endpoint for supporting bucket notifications in a MinIO deployment.

Important

This procedure requires restarting all minio server processes associated to the deployment at the same time. There is typically a brief period of time during which API operations are interrupted or may fail.

Applications using an S3-compatible SDK with built-in retry logic or which implement manual retry logic typically experience no notable interruption in services. For applications which cannot use retry-logic, consider scheduling a maintenance period to minimize interruption of services while performing this procedure.

Prerequisites

MinIO mc Command Line Tool

This procedure uses the mc command line tool for certain actions. See the mc Quickstart for installation instructions.

1) List Configured NATS Endpoints In The Deployment

Use the mc admin config get command to list the currently configured NATS service endpoints in the deployment:

mc admin config get ALIAS/ notify_nats

Replace ALIAS with the alias of the MinIO deployment.

The command output resembles the following:

notify_nats:primary password="yoursecret" streaming_max_pub_acks_in_flight="10" subject="" address="nats-endpoint.example.com: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"
notify_nats:secondary password="yoursecret" streaming_max_pub_acks_in_flight="10" subject="" address="nats-endpoint.example.com: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"

The notify_nats key is the top-level configuration key for an NATS Service for Bucket Notifications. The address key specifies the NATS service endpoint for the given notify_nats key. The notify_nats:<IDENTIFIER> suffix describes the unique identifier for that NATS service endpoint.

Note the identifier for the NATS service endpoint you want to update for the next step.

2) Update the NATS Endpoint

Use the mc admin config set command to set the new configuration for the NATS service endpoint:

mc admin config set ALIAS/ notify_nats:IDENTIFIER \
   address="HOSTNAME" \
   subject="<string>" \
   username="<string>" \
   password="<string>" \
   token="<string>" \
   tls="<string>" \
   tls_skip_verify="<string>" \
   ping_interval="<string>" \
   streaming="<string>" \
   streaming_async="<string>" \
   streaming_max_pub_acks_in_flight="<string>" \
   streaming_cluster_id="<string>" \
   cert_authority="<string>" \
   client_cert="<string>" \
   client_key="<string>" \
   queue_dir="<string>" \
   queue_limit="<string>" \
   comment="<string>"

The notify_nats address configuration setting is the minimum required for an NATS service endpoint. All other configuration settings are optional. See NATS Service for Bucket Notifications for a complete list of NATS configuration settings.

3) Restart the MinIO Deployment

You must restart the MinIO deployment to apply the configuration changes. Use the mc admin service restart command to restart the deployment.

Important

MinIO restarts all minio server processes associated to the deployment at the same time. Applications may experience a brief period of downtime during the restart process.

Consider scheduling the restart during a maintenance period to minimize interruption of services.

mc admin service restart ALIAS

Replace ALIAS with the alias of the deployment to restart.

The minio server process prints a line on startup for each configured NATS target similar to the following:

SQS ARNs: arn:minio:sqs::primary:nats

3) Validate the Changes

Perform an action on a bucket which has an event configuration using the updated NATS service endpoint and check the NATS service for the notification data. The action required depends on which events were specified when configuring the bucket notification.

For example, if the bucket notification configuration includes the s3:ObjectCreated:Put event, you can use the mc cp command to create a new object in the bucket and trigger a notification.

mc cp ~/data/new-object.txt ALIAS/BUCKET