Publish Events to Redis

AIStor supports publishing bucket notification events to a Redis service endpoint.

Prerequisites

The AIStor mc command line tool

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

Add a Redis endpoint to an AIStor Server

The following procedure adds a new Redis service endpoint for supporting bucket notifications in an AIStor Server.

Add the Redis endpoint to AIStor.

You can configure a new Redis service endpoint using either environment variables or by setting runtime configuration settings.
Environment Variables
AIStor supports specifying the Redis service endpoint and associated configuration settings using environment variables. The minio server process applies the specified settings on its next startup.

The minimum required variables are:
The following example code sets all environment variables related to configuring a Redis service endpoint.
```
export MINIO_NOTIFY_REDIS_ENABLE_<IDENTIFIER>="on"
export MINIO_NOTIFY_REDIS_ADDRESS_<IDENTIFIER>="<ENDPOINT>"
export MINIO_NOTIFY_REDIS_KEY_<IDENTIFIER>="<STRING>"
export MINIO_NOTIFY_REDIS_FORMAT_<IDENTIFIER>="<string>"
export MINIO_NOTIFY_REDIS_PASSWORD_<IDENTIFIER>="<string>"
export MINIO_NOTIFY_REDIS_QUEUE_DIR_<IDENTIFIER>="<string>"
export MINIO_NOTIFY_REDIS_QUEUE_LIMIT_<IDENTIFIER>="<string>"
export MINIO_NOTIFY_REDIS_COMMENT_<IDENTIFIER>="<string>"
```
- Replace <IDENTIFIER> with a unique descriptive string for the TARGET 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 Redis service endpoint on the AIStor Server, the new settings override any existing settings for that endpoint. Use mc admin config get notify_redis to review the currently configured Redis endpoints on the AIStor Server.
- Replace <ENDPOINT> with the URL of the Redis service endpoint. For example: https://redis.example.com:6369
See Redis Service for Bucket Notifications for complete documentation on each environment variable.
Configuration Settings
AIStor supports adding or updating Redis endpoints on a running minio server process using the mc admin config set command and the notify_redis configuration key. You must restart the minio server process to apply any new or updated configuration settings.

The minimum required settings are:
The following example code sets all available settings related to configuring a Redis service endpoint.
```
mc admin config set ALIAS notify_redis:IDENTIFIER \
  address="ENDPOINT" \
  key="<string>" \
  format="<string>" \
  password="<string>" \
  queue_dir="<string>" \
  queue_limit="<string>" \
  comment="<string>"
```
- Replace IDENTIFIER with a unique descriptive string for the Redis service endpoint. The following examples in this procedure assume an identifier of PRIMARY.
  
  If the specified IDENTIFIER matches an existing Redis service endpoint on the AIStor Server, the new settings override any existing settings for that endpoint. Use mc admin config get notify_redis to review the currently configured Redis endpoints on the AIStor Server.
- Replace ENDPOINT with the URL of the Redis service endpoint. For example: https://redis.example.com:6369
See Redis Bucket Notification Configuration Settings for complete documentation on each setting.
If you define both environment variables and configuration settings for the deployment, the settings defined by environment variables are used.
Restart the AIStor Server.

You must restart the AIStor Server to apply the configuration changes. Use the mc admin service restart command to restart the deployment.
```
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 Redis target similar to the following:
```
SQS ARNs: arn:minio:sqs::primary:redis
```
You must specify the ARN resource when configuring bucket notifications with the associated Redis deployment as a target.
Configure bucket notifications using the Redis endpoint as a target.

Use the mc event add command to add a new bucket notification event with the configured Redis service as a target:
```
mc event add ALIAS/BUCKET arn:minio:sqs::primary:redis \
  --event EVENTS
```
- Replace ALIAS with the alias of an AIStor Server.
- 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 AIStor triggers notifications.
Use mc event ls to view all configured bucket events for a given notification target:
```
mc event ls ALIAS/BUCKET arn:minio:sqs::primary:redis
```
Validate the configured events.

Perform an action on the bucket for which you configured the new event and check the Redis 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 a Redis Endpoint in an AIStor Server

The following procedure updates an existing Redis service endpoint for supporting bucket notifications in an AIStor Server.

List configured Redis endpoints in the deployment.

Use the mc admin config get command to list the currently configured Redis service endpoints in the deployment:
```
mc admin config get ALIAS notify_redis
```
Replace ALIAS with the alias of the AIStor Server.

The command output resembles the following:
```
notify_redis:primary address="https://redis.example.com:6369" format="namespace" key="minioevent" password="" queue_dir="" queue_limit="0"
notify_redis:secondary address="https://redis.example.com:6369" format="namespace" key="minioevent" password="" queue_dir="" queue_limit="0"
```
The notify_redis key is the top-level configuration key for a Redis Notification Settings. The address key specifies the Redis service endpoint for the given notify_redis key. The notify_redis:<IDENTIFIER> suffix describes the unique identifier for that Redis service endpoint.

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

Use the mc admin config set command to set the new configuration for the Redis service endpoint:
```
mc admin config set ALIAS notify_redis:IDENTIFIER \
   address="ENDPOINT" \
   key="<string>" \
   format="<string>" \
   password="<string>" \
   queue_dir="<string>" \
   queue_limit="<string>" \
   comment="<string>"
```
The notify_redis address configuration setting is the minimum required for a Redis service endpoint. All other configuration settings are optional. See Redis Notification Settings for a complete list of Redis configuration settings.
Restart the AIStor Server.

You must restart the AIStor Server to apply the configuration changes. Use the mc admin service restart command to restart the deployment.
```
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 Redis target similar to the following:
```
SQS ARNs: arn:minio:sqs::primary:redis
```
Validate the changes.

Perform an action on a bucket which has an event configuration using the updated Redis service endpoint and check the Redis 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
```