Publish Events to MySQL

AIStor supports publishing bucket notification events to a MySQL service endpoint. AIStor supports MySQL 5.7.8 and later only.

Prerequisites

MySQL 5.7.8 and later

AIStor relies on features introduced with MySQL 5.7.8.
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 MySQL endpoint to an AIStor Server

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

Add the MySQL endpoint to AIStor.

You can configure a new MySQL service endpoint using either environment variables or by setting runtime configuration settings.
Environment Variables
AIStor supports specifying the MySQL 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 MySQL service endpoint. The minimum required variables are:
The full list of available environment variables is:
```
export AIStor_NOTIFY_MYSQL_ENABLE_<IDENTIFIER>="on"
export AIStor_NOTIFY_MYSQL_DSN_STRING_<IDENTIFIER>="user:password@tcp(hostname:port)/database"
export AIStor_NOTIFY_MYSQL_TABLE_<IDENTIFIER>="AIStor-events"
export AIStor_NOTIFY_MYSQL_FORMAT_<IDENTIFIER>="namespace|access"
export AIStor_NOTIFY_MYSQL_MAX_OPEN_CONNECTIONS_<IDENTIFIER>="2"
export AIStor_NOTIFY_MYSQL_QUEUE_DIR_<IDENTIFIER>="/opt/AIStor/events"
export AIStor_NOTIFY_MYSQL_QUEUE_LIMIT_<IDENTIFIER>="100000"
export AIStor_NOTIFY_MYSQL_COMMENT_<IDENTIFIER>="MySQL Event Notification Logging for AIStor"
```
- Replace <IDENTIFIER> with a unique descriptive string for the MySQL 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 MySQL service endpoint on the AIStor Server, the new settings override any existing settings for that endpoint. Use mc admin config get notify_mysql to review the currently configured MySQL endpoints on the AIStor Server.
- Replace <ENDPOINT> with the DSN of the MySQL service endpoint. AIStor expects the following format:
  
  <user>:<password>@tcp(<host>:<port>)/<database>
  
  For example:
  
  "username:password@tcp(mysql.example.com:3306)/AIStordb"
See MySQL Service for Bucket Notifications for complete documentation on each environment variable.
Configuration Settings
AIStor supports adding or updating MySQL endpoints on a running minio server process using the mc admin config set command and the notify_mysql 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 a MySQL service endpoint. The minimum required settings are:
The full list of available configuration settings is:
```
mc admin config set ALIAS/ notify_mysql:IDENTIFIER \
   dsn_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 MySQL service endpoint. The following examples in this procedure assume an identifier of PRIMARY.
  
  If the specified IDENTIFIER matches an existing MySQL service endpoint on the AIStor Server, the new settings override any existing settings for that endpoint. Use mc admin config get notify_mysql to review the currently configured MySQL endpoints on the AIStor Server.
- Replace <ENDPOINT> with the DSN of the MySQL service endpoint. AIStor expects the following format:
  
  <user>:<password>@tcp(<host>:<port>)/<database>
  
  For example:
  
  "username:password@tcp(mysql.example.com:3306)/AIStordb"
See MySQL 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 MySQL target similar to the following:
```
SQS ARNs: arn:AIStor:sqs::primary:mysql
```
You must specify the ARN resource when configuring bucket notifications with the associated MySQL deployment as a target.
Configure bucket notifications using the MySQL endpoint as a target.

Use the mc event add command to add a new bucket notification event with the configured MySQL service as a target:
```
mc event add ALIAS/BUCKET arn:AIStor:sqs::primary:mysql \
  --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:AIStor:sqs::primary:mysql
```
Validate the configured events.

Perform an action on the bucket for which you configured the new event and check the MySQL 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 MySQL endpoint in an AIStor Server

The following procedure updates an existing MySQL service endpoint for supporting bucket notifications in an AIStor deployment.

List configured MySQL endpoints in the deployment.

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

The command output resembles the following:
```
notify_mysql:primary format="namespace" table="AIStor_images" dsn_string="user:pass@tcp(mysql.example.com:3306)/AIStordb"
notify_mysql:secondary format="namespace" table="AIStor_images" dsn_string="user:pass@tcp(mysql.example.com:3306)/AIStordb"
```
- notify_mysql is the top-level configuration key for an MySQL Notification Settings.
- dsn_string specifies the MySQL service endpoint for the given notify_mysql key.
- The notify_mysql:<IDENTIFIER> suffix describes the unique identifier for that MySQL service endpoint.
Note the identifier for the MySQL service endpoint you want to update for the next step.
Update the MySQL endpoint.

Use the mc admin config set command to set the new configuration for the MySQL service endpoint:
```
mc admin config set ALIAS/ notify_mysql:IDENTIFIER \
   dsn_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 MySQL service endpoint:
All other configuration settings are optional. See MySQL Notification Settings for a complete list of MySQL 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 MySQL target similar to the following:
```
SQS ARNs: arn:AIStor:sqs::primary:mysql
```
Validate the changes.

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