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Publish Events to PostgreSQL

MinIO supports publishing bucket notification events to PostgreSQL. MinIO supports PostgreSQL 9.5 and later only.

Add a PostgreSQL Endpoint to a MinIO Deployment

The following procedure adds a new PostgreSQL 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

PostgreSQL 9.5 and later

MinIO relies on features introduced with PostgreSQL 9.5.

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 PostgreSQL Endpoint to MinIO

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

MinIO supports specifying the PostgreSQL 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 a PostgreSQL service endpoint. The minimum required variables are:

set MINIO_NOTIFY_CONNECTION_STRING_<IDENTIFIER>="on"
set MINIO_NOTIFY_TABLE_<IDENTIFIER>="ENDPOINT"
set MINIO_NOTIFY_FORMAT_<IDENTIFIER>=""
set MINIO_NOTIFY_MAX_OPEN_CONNECTIONS_<IDENTIFIER>=""
set MINIO_NOTIFY_QUEUE_DIR_<IDENTIFIER>=""
set MINIO_NOTIFY_QUEUE_LIMIT_<IDENTIFIER>=""
set MINIO_NOTIFY_COMMENT_<IDENTIFIER>=""
  • Replace <IDENTIFIER> with a unique descriptive string for the PostgreSQL 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 PostgreSQL service endpoint on the MinIO deployment, the new settings override any existing settings for that endpoint. Use mc admin config get notify_postgresql to review the currently configured PostgreSQL endpoints on the MinIO deployment.

  • Replace <ENDPOINT> with the PostgreSQL Connection String for PostgreSQL service endpoint. MinIO supports key=value format for the connection string. For example:

    "host=https://postgresql.example.com port=5432 ..."

    For more complete documentation on supported PostgreSQL connection string parameters, see PostgreSQL Connection String.

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

MinIO supports adding or updating PostgreSQL endpoints on a running minio server process using the mc admin config set command and the notify_postgresql 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 PostgreSQL service endpoint. The minimum required setting are:

mc admin config set ALIAS/ notify_postgresql:IDENTIFIER \
   connection_string="ENDPOINT" \
   table="<string>" \
   format="<string>" \
   max_open_connections="<string>" \
   queue_dir="<string>" \
   queue_limit="<string>" \
   comment="<string>"
  • Replace IDENTIFIER with a unique descriptive string for the PostgreSQL service endpoint. The following examples in this procedure assume an identifier of PRIMARY.

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

  • Replace <ENDPOINT> with the PostgreSQL URI connection string of the PostgreSQL service endpoint. MinIO supports key=value format for the PostgreSQL connection string. For example:

    "host=https://postgresql.example.com port=5432 ..."

    For more complete documentation on supported PostgreSQL connection string parameters, see PostgreSQL Connection String.

See PostgreSQL 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 PostgreSQL target similar to the following:

SQS ARNs: arn:minio:sqs::primary:postgresql

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

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

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

mc event add ALIAS/BUCKET arn:minio:sqs::primary:postgresql \
  --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:postgresql

4) Validate the Configured Events

Perform an action on the bucket for which you configured the new event and check the PostgreSQL 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 PostgreSQL Endpoint in a MinIO Deployment

The following procedure updates an existing PostgreSQL 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

PostgreSQL 9.5 and later

MinIO relies on features introduced with PostgreSQL 9.5.

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 PostgreSQL Endpoints In The Deployment

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

mc admin config get ALIAS/ notify_postgresql

Replace ALIAS with the alias of the MinIO deployment.

The command output resembles the following:

notify_postgresql:primary queue_dir="" connection_string="postgresql://" queue_limit="0"  table="" format="namespace"
notify_postgresql:secondary queue_dir="" connection_string="" queue_limit="0"  table="" format="namespace"

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

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

2) Update the PostgreSQL Endpoint

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

mc admin config set ALIAS/ notify_postgresql:IDENTIFIER \
   connection_string="ENDPOINT" \
   table="<string>" \
   format="<string>" \
   max_open_connections="<string>" \
   queue_dir="<string>" \
   queue_limit="<string>" \
   comment="<string>"

The following configuration settings are the minimum required for a PostgreSQL service endpoint:

All other configuration settings are optional. See PostgreSQL Service for Bucket Notifications for a complete list of PostgreSQL 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 PostgreSQL target similar to the following:

SQS ARNs: arn:minio:sqs::primary:postgresql

3) Validate the Changes

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