Publish Events to NSQ

AIStor supports publishing bucket notification events to NSQ 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 an NSQ endpoint to an AIStor Server

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

Add the NSQ Endpoint to AIStor.

You can configure a new NSQ service endpoint using either environment variables or by setting runtime configuration settings.
Environment Variables
AIStor supports specifying the NSQ 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:
- MINIO_NOTIFY_NSQ_NSQD_ADDRESS
- MINIO_NOTIFY_NSQ_TOPIC
The following example code sets all environment variables related to configuring an NSQ service endpoint.
```
export MINIO_NOTIFY_NSQ_ENABLE_<IDENTIFIER>="on"
export MINIO_NOTIFY_NSQ_NSQD_ADDRESS_<IDENTIFIER>="<ENDPOINT>"
export MINIO_NOTIFY_NSQ_TOPIC_<IDENTIFIER>="<string>"
export MINIO_NOTIFY_NSQ_TLS_<IDENTIFIER>="<string>"
export MINIO_NOTIFY_NSQ_TLS_SKIP_VERIFY_<IDENTIFIER>="<string>"
export MINIO_NOTIFY_NSQ_QUEUE_DIR_<IDENTIFIER>="<string>"
export MINIO_NOTIFY_NSQ_QUEUE_LIMIT_<IDENTIFIER>="<string>"
export MINIO_NOTIFY_NSQ_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 NSQ service endpoint on the AIStor Server, the new settings override any existing settings for that endpoint. Use mc admin config get notify_nsq to review the currently configured NSQ endpoints on the AIStor Server.
- Replace <ENDPOINT> with the URL of the NSQ service endpoint. For example, https://nsq-service.example.com:4150.
See NSQ Service for Bucket Notifications for complete documentation on each environment variable.
Configuration Settings
AIStor supports adding or updating NSQ endpoints on a running minio server process using the mc admin config set command and the notify_nsq configuration key. You must restart the minio server process to apply any new or updated configuration settings.

The minimum required settings are:
- notify_nsq nsqd_address
- notify_nsq topic
The following example code sets all settings related to configuring an NSQ service endpoint.
```
mc admin config set ALIAS notify_nsq:IDENTIFIER \
  nsqd_address="ENDPOINT" \
  topic="<string>" \
  tls="<string>" \
  tls_skip_verify="<string>" \
  queue_dir="<string>" \
  queue_limit="<string>" \
  comment="<string>"
```
- Replace IDENTIFIER with a unique descriptive string for the NSQ service endpoint. The following examples in this procedure assume an identifier of PRIMARY.
  
  If the specified IDENTIFIER matches an existing NSQ service endpoint on the AIStor Server, the new settings override any existing settings for that endpoint. Use mc admin config get notify_nsq to review the currently configured NSQ endpoints on the AIStor Server.
- Replace ENDPOINT with the URL of the NSQ service endpoint. For example:
  
  NSQ://user:password@hostname:port
See NSQ 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 NSQ target similar to the following:
```
SQS ARNs: |ARN|
```
You must specify the ARN resource when configuring bucket notifications with the associated NSQ deployment as a target.
Configure bucket notifications using the NSQ endpoint as a target.

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

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

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

List configured NSQ endpoints in the deployment.

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

The command output resembles the following:
```
notify_nsq:primary nsqd_address="https://nsq.example.com" queue_dir="" queue_limit="0"  tls="off" tls_skip_verify="off" topic=""
notify_nsq:secondary nsqd_address="https://nsq.example.com" queue_dir="" queue_limit="0"  tls="off" tls_skip_verify="off" topic=""
```
- notify_nsq is the top-level configuration key for an NSQ Notification Settings.
- nsqd_address specifies the NSQ service endpoint for the given notify_nsq key.
- The notify_nsq:<IDENTIFIER> suffix describes the unique identifier for that NSQ service endpoint.
Note the identifier for the NSQ service endpoint you want to update for the next step.
Update the NSQ endpoint.

Use the mc admin config set command to set the new configuration for the NSQ service endpoint:
```
mc admin config set ALIAS notify_nsq:<IDENTIFIER> \
   nsqd_address="NSQ://user:password@hostname:port" \
   topic="<string>" \
   tls="<string>" \
   tls_skip_verify="<string>" \
   queue_dir="<string>" \
   queue_limit="<string>" \
   comment="<string>"
```
notify_nsq nsqd_address is the minimum required setting for an NSQ service endpoint. All other configuration settings are optional. See NSQ Notification Settings for a complete list of NSQ 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 NSQ target similar to the following:
```
SQS ARNs: arn:minio:sqs::primary:NSQ
```
Validate the changes.

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