Minio Bucket Notification Guide Slack

Changes in a bucket, such as object uploads and removal, can be monitored using bucket event notification
mechanism and can be published to the following targets:

Notification Targets
AMQP
Elasticsearch
Redis
NATS
PostgreSQL
MySQL
Apache Kafka
Webhooks

Prerequisites

Publish Minio events via AMQP

Install RabbitMQ from here.

Step 1: Add AMQP endpoint to Minio

The default location of Minio server configuration file is ~/.minio/config.json. The AMQP configuration is located in the amqp key under the notify top-level key. Create a configuration key-value pair here for your AMQP instance. The key is a name for your AMQP endpoint, and the value is a collection of key-value parameters described in the table below.

Parameter Type Description
enable bool (Required) Is this server endpoint configuration active/enabled?
url string (Required) AMQP server endpoint, e.g. amqp://myuser:mypassword@localhost:5672
exchange string Name of the exchange.
routingKey string Routing key for publishing.
exchangeType string Kind of exchange.
deliveryMode uint8 Delivery mode for publishing. 0 or 1 - transient; 2 - persistent.
mandatory bool Publishing related bool.
immediate bool Publishing related bool.
durable bool Exchange declaration related bool.
internal bool Exchange declaration related bool.
noWait bool Exchange declaration related bool.
autoDeleted bool Exchange declaration related bool.

An example configuration for RabbitMQ is shown below:

"amqp": {
    "1": {
        "enable": true,
        "url": "amqp://myuser:mypassword@localhost:5672",
        "exchange": "bucketevents",
        "routingKey": "bucketlogs",
        "exchangeType": "fanout",
        "deliveryMode": 0,
        "mandatory": false,
        "immediate": false,
        "durable": false,
        "internal": false,
        "noWait": false,
        "autoDeleted": false
    }
}

After updating the configuration file, restart the Minio server to put the changes into effect. The server will print a line like SQS ARNs: arn:minio:sqs:us-east-1:1:amqp at start-up if there were no errors.

Minio supports all the exchanges available in RabbitMQ. For this setup, we are using fanout exchange.

Note that, you can add as many AMQP server endpoint configurations as needed by providing an identifier (like "1" in the example above) for the AMQP instance and an object of per-server configuration parameters.

Step 2: Enable bucket notification using Minio client

We will enable bucket event notification to trigger whenever a JPEG image is uploaded or deleted images bucket on myminio server. Here ARN value is arn:minio:sqs:us-east-1:1:amqp. To understand more about ARN please follow AWS ARN documentation.

mc mb myminio/images
mc events add  myminio/images arn:minio:sqs:us-east-1:1:amqp --suffix .jpg
mc events list myminio/images
arn:minio:sqs:us-east-1:1:amqp s3:ObjectCreated:*,s3:ObjectRemoved:* Filter: suffix=”.jpg”

Step 3: Test on RabbitMQ

The python program below waits on the queue exchange bucketevents and prints event notifications on the console. We use Pika Python Client library to do this.

#!/usr/bin/env python
import pika

connection = pika.BlockingConnection(pika.ConnectionParameters(
        host='localhost'))
channel = connection.channel()

channel.exchange_declare(exchange='bucketevents',
                         type='fanout')

result = channel.queue_declare(exclusive=False)
queue_name = result.method.queue

channel.queue_bind(exchange='bucketevents',
                   queue=queue_name)

print(' [*] Waiting for logs. To exit press CTRL+C')

def callback(ch, method, properties, body):
    print(" [x] %r" % body)

channel.basic_consume(callback,
                      queue=queue_name,
                      no_ack=False)

channel.start_consuming()

Execute this example python program to watch for RabbitMQ events on the console.

python rabbit.py

Open another terminal and upload a JPEG image into images bucket.

mc cp myphoto.jpg myminio/images

You should receive the following event notification via RabbitMQ once the upload completes.

python rabbit.py
‘{“Records”:[{“eventVersion”:”2.0",”eventSource”:”aws:s3",”awsRegion”:”us-east-1",”eventTime”:”2016–09–08T22:34:38.226Z”,”eventName”:”s3:ObjectCreated:Put”,”userIdentity”:{“principalId”:”minio”},”requestParameters”:{“sourceIPAddress”:”10.1.10.150:44576"},”responseElements”:{},”s3":{“s3SchemaVersion”:”1.0",”configurationId”:”Config”,”bucket”:{“name”:”images”,”ownerIdentity”:{“principalId”:”minio”},”arn”:”arn:aws:s3:::images”},”object”:{“key”:”myphoto.jpg”,”size”:200436,”sequencer”:”147279EAF9F40933"}}}],”level”:”info”,”msg”:””,”time”:”2016–09–08T15:34:38–07:00"}\n

Publish Minio events via Elasticsearch

Install Elasticsearch server. Minio server supports the latest major release series 5.x. Elasticsearch provides version upgrade migration guidelines here.

This notification target supports two formats: namespace and access.

When the namespace format is used, Minio synchronizes objects in the bucket with documents in the index. For each event in the Minio, the server creates a document with the bucket and object name from the event as the document ID. Other details of the event are stored in the body of the document. Thus if an existing object is over-written in Minio, the corresponding document in the Elasticsearch index is updated. If an object is deleted, the corresponding document is deleted from the index.

When the access format is used, Minio appends events as documents in an Elasticsearch index. For each event, a document with the event details, with the timestamp of document set to the event's timestamp is appended to an index. The ID of the documented is randomly generated by Elasticsearch. No documents are deleted or modified in this format.

The steps below show how to use this notification target in namespace format. The other format is very similar and is omitted for brevity.

Step 1: Add Elasticsearch endpoint to Minio

The default location of Minio server configuration file is ~/.minio/config.json. The Elasticsearch configuration is located in the elasticsearch key under the notify top-level key. Create a configuration key-value pair here for your Elasticsearch instance. The key is a name for your Elasticsearch endpoint, and the value is a collection of key-value parameters described in the table below.

Parameter Type Description
enable bool (Required) Is this server endpoint configuration active/enabled?
format string (Required) Either namespace or access.
url string (Required) The Elasticsearch server's address. For example: http://localhost:9200.
index string (Required) The name of an Elasticsearch index in which Minio will store documents.

An example of Elasticsearch configuration is as follows:

"elasticsearch": {
    "1": {
        "enable": true,
        "format": "namespace",
        "url": "http://127.0.0.1:9200",
        "index": "minio_events"
    }
},

After updating the configuration file, restart the Minio server to put the changes into effect. The server will print a line like SQS ARNs: arn:minio:sqs:us-east-1:1:elasticsearch at start-up if there were no errors.

Note that, you can add as many Elasticsearch server endpoint configurations as needed by providing an identifier (like "1" in the example above) for the Elasticsearch instance and an object of per-server configuration parameters.

Step 2: Enable bucket notification using Minio client

We will now enable bucket event notifications on a bucket named images. Whenever a JPEG image is created/overwritten, a new document is added or an existing document is updated in the Elasticsearch index configured above. When an existing object is deleted, the corresponding document is deleted from the index. Thus, the rows in the Elasticsearch index, reflect the .jpg objects in the images bucket.

To configure this bucket notification, we need the ARN printed by Minio in the previous step. Additional information about ARN is available here.

With the mc tool, the configuration is very simple to add. Let us say that the Minio server is aliased as myminio in our mc configuration. Execute the following:

mc mb myminio/images
mc events add  myminio/images arn:minio:sqs:us-east-1:1:elasticsearch --suffix .jpg
mc events list myminio/images
arn:minio:sqs:us-east-1:1:elasticsearch s3:ObjectCreated:*,s3:ObjectRemoved:* Filter: suffix=”.jpg”

Step 3: Test on Elasticsearch

Upload a JPEG image into images bucket.

mc cp myphoto.jpg myminio/images

Use curl to view contents of minio_events index.

$ curl  "http://localhost:9200/minio_events/_search?pretty=true"
{
  "took" : 40,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "failed" : 0
  },
  "hits" : {
    "total" : 1,
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "minio_events",
        "_type" : "event",
        "_id" : "images/myphoto.jpg",
        "_score" : 1.0,
        "_source" : {
          "Records" : [
            {
              "eventVersion" : "2.0",
              "eventSource" : "minio:s3",
              "awsRegion" : "us-east-1",
              "eventTime" : "2017-03-30T08:00:41Z",
              "eventName" : "s3:ObjectCreated:Put",
              "userIdentity" : {
                "principalId" : "minio"
              },
              "requestParameters" : {
                "sourceIPAddress" : "127.0.0.1:38062"
              },
              "responseElements" : {
                "x-amz-request-id" : "14B09A09703FC47B",
                "x-minio-origin-endpoint" : "http://192.168.86.115:9000"
              },
              "s3" : {
                "s3SchemaVersion" : "1.0",
                "configurationId" : "Config",
                "bucket" : {
                  "name" : "images",
                  "ownerIdentity" : {
                    "principalId" : "minio"
                  },
                  "arn" : "arn:aws:s3:::images"
                },
                "object" : {
                  "key" : "myphoto.jpg",
                  "size" : 6474,
                  "eTag" : "a3410f4f8788b510d6f19c5067e60a90",
                  "sequencer" : "14B09A09703FC47B"
                }
              },
              "source" : {
                "host" : "127.0.0.1",
                "port" : "38062",
                "userAgent" : "Minio (linux; amd64) minio-go/2.0.3 mc/2017-02-15T17:57:25Z"
              }
            }
          ]
        }
      }
    ]
  }
}

This output shows that a document has been created for the event in Elasticsearch.

Here we see that the document ID is the bucket and object name. In case access format was used, the document ID would be automatically generated by Elasticsearch.

Publish Minio events via Redis

Install Redis server. For illustrative purposes, we have set the database password as "yoursecret".

This notification target supports two formats: namespace and access.

When the namespace format is used, Minio synchronizes objects in the bucket with entries in a hash. For each entry, the key is formatted as "bucketName/objectName" for an object that exists in the bucket, and the value is the JSON-encoded event data about the operation that created/replaced the object in Minio. When objects are updated or deleted, the corresponding entry int he hash is updated or deleted respectively.

When the access format is used, Minio appends events to a list using RPUSH. Each item in the list is a JSON encoded list with two items, where the first item is a timestamp string, and second item is a JSON object containing evnet data about the operation that happened in the bucket. No entries appended to the list are updated or deleted by Minio in this format.

The steps below show how to use this notification target in namespace and access format.

Step 1: Add Redis endpoint to Minio

The default location of Minio server configuration file is ~/.minio/config.json. The Redis configuration is located in the redis key under the notify top-level key. Create a configuration key-value pair here for your Redis instance. The key is a name for your Redis endpoint, and the value is a collection of key-value parameters described in the table below.

Parameter Type Description
enable bool (Required) Is this server endpoint configuration active/enabled?
format string (Required) Either namespace or access.
address string (Required) The Redis server's address. For example: localhost:6379.
password string (Optional) The Redis server's password.
key string (Required) The name of the redis key under which events are stored. A hash is used in case of namespace format and a list in case of access format.

An example of Redis configuration is as follows:

"redis": {
    "1": {
        "enable": true,
        "address": "127.0.0.1:6379",
        "password": "yoursecret",
        "key": "bucketevents"
    }
}

After updating the configuration file, restart the Minio server to put the changes into effect. The server will print a line like SQS ARNs: arn:minio:sqs:us-east-1:1:redis at start-up if there were no errors.

Note that, you can add as many Redis server endpoint configurations as needed by providing an identifier (like "1" in the example above) for the Redis instance and an object of per-server configuration parameters.

Step 2: Enable bucket notification using Minio client

We will now enable bucket event notifications on a bucket named images. Whenever a JPEG image is created/overwritten, a new key is added or an existing key is updated in the Redis hash configured above. When an existing object is deleted, the corresponding key is deleted from the Redis hash. Thus, the rows in the Redis hash, reflect the .jpg objects in the images bucket.

To configure this bucket notification, we need the ARN printed by Minio in the previous step. Additional information about ARN is available here.

With the mc tool, the configuration is very simple to add. Let us say that the Minio server is aliased as myminio in our mc configuration. Execute the following:

mc mb myminio/images
mc events add  myminio/images arn:minio:sqs:us-east-1:1:redis --suffix .jpg
mc events list myminio/images
arn:minio:sqs:us-east-1:1:redis s3:ObjectCreated:*,s3:ObjectRemoved:* Filter: suffix=”.jpg”

Step 3: Test on Redis

Start the redis-cli Redis client program to inspect the contents in Redis. Run the monitor Redis command. This prints each operation performed on Redis as it occurs.

redis-cli -a yoursecret
127.0.0.1:6379> monitor
OK

Open another terminal and upload a JPEG image into images bucket.

mc cp myphoto.jpg myminio/images

In the previous terminal, you will now see the operation that Minio performs on Redis:

127.0.0.1:6379> monitor
OK
1490686879.650649 [0 172.17.0.1:44710] "PING"
1490686879.651061 [0 172.17.0.1:44710] "HSET" "minio_events" "images/myphoto.jpg" "{\"Records\":[{\"eventVersion\":\"2.0\",\"eventSource\":\"minio:s3\",\"awsRegion\":\"us-east-1\",\"eventTime\":\"2017-03-28T07:41:19Z\",\"eventName\":\"s3:ObjectCreated:Put\",\"userIdentity\":{\"principalId\":\"minio\"},\"requestParameters\":{\"sourceIPAddress\":\"127.0.0.1:52234\"},\"responseElements\":{\"x-amz-request-id\":\"14AFFBD1ACE5F632\",\"x-minio-origin-endpoint\":\"http://192.168.86.115:9000\"},\"s3\":{\"s3SchemaVersion\":\"1.0\",\"configurationId\":\"Config\",\"bucket\":{\"name\":\"images\",\"ownerIdentity\":{\"principalId\":\"minio\"},\"arn\":\"arn:aws:s3:::images\"},\"object\":{\"key\":\"myphoto.jpg\",\"size\":2586,\"eTag\":\"5d284463f9da279f060f0ea4d11af098\",\"sequencer\":\"14AFFBD1ACE5F632\"}},\"source\":{\"host\":\"127.0.0.1\",\"port\":\"52234\",\"userAgent\":\"Minio (linux; amd64) minio-go/2.0.3 mc/2017-02-15T17:57:25Z\"}}]}"

Here we see that Minio performed HSET on minio_events key.

In case, access format was used, then minio_events would be a list, and the Minio server would have performed an RPUSH to append to the list. A consumer of this list would ideally use BLPOP to remove list items from the left-end of the list.

Publish Minio events via NATS

Install NATS from here.

Step 1: Add NATS endpoint to Minio

The default location of Minio server configuration file is ~/.minio/config.json. Update the NATS configuration block in config.json as follows:

"nats": {
    "1": {
        "enable": true,
        "address": "0.0.0.0:4222",
        "subject": "bucketevents",
        "username": "yourusername",
        "password": "yoursecret",
        "token": "",
        "secure": false,
        "pingInterval": 0
    }
},

Restart Minio server to reflect config changes. bucketevents is the subject used by NATS in this example.

Step 2: Enable bucket notification using Minio client

We will enable bucket event notification to trigger whenever a JPEG image is uploaded or deleted from images bucket on myminio server. Here ARN value is arn:minio:sqs:us-east-1:1:nats. To understand more about ARN please follow AWS ARN documentation.

mc mb myminio/images
mc events add  myminio/images arn:minio:sqs:us-east-1:1:nats --suffix .jpg
mc events list myminio/images
arn:minio:sqs:us-east-1:1:nats s3:ObjectCreated:*,s3:ObjectRemoved:* Filter: suffix=”.jpg”

Step 3: Test on NATS

Using this program below we can log the bucket notification added to NATS.

package main

// Import Go and NATS packages
import (
    "log"
    "runtime"

    "github.com/nats-io/nats"
)

func main() {

    // Create server connection
    natsConnection, _ := nats.Connect("nats://yourusername:yoursecret@localhost:4222")
    log.Println("Connected")

    // Subscribe to subject
    log.Printf("Subscribing to subject 'bucketevents'\n")
    natsConnection.Subscribe("bucketevents", func(msg *nats.Msg) {

        // Handle the message
        log.Printf("Received message '%s\n", string(msg.Data)+"'")
    })

    // Keep the connection alive
    runtime.Goexit()
}
go run nats.go
2016/10/12 06:39:18 Connected
2016/10/12 06:39:18 Subscribing to subject 'bucketevents'

Open another terminal and upload a JPEG image into images bucket.

mc cp myphoto.jpg myminio/images

The example nats.go program prints event notification to console.

go run nats.go
2016/10/12 06:51:26 Connected
2016/10/12 06:51:26 Subscribing to subject 'bucketevents'
2016/10/12 06:51:33 Received message '{"EventType":"s3:ObjectCreated:Put","Key":"images/myphoto.jpg","Records":[{"eventVersion":"2.0","eventSource":"aws:s3","awsRegion":"us-east-1","eventTime":"2016-10-12T13:51:33Z","eventName":"s3:ObjectCreated:Put","userIdentity":{"principalId":"minio"},"requestParameters":{"sourceIPAddress":"[::1]:57106"},"responseElements":{},"s3":{"s3SchemaVersion":"1.0","configurationId":"Config","bucket":{"name":"images","ownerIdentity":{"principalId":"minio"},"arn":"arn:aws:s3:::images"},"object":{"key":"myphoto.jpg","size":56060,"eTag":"1d97bf45ecb37f7a7b699418070df08f","sequencer":"147CCD1AE054BFD0"}}}],"level":"info","msg":"","time":"2016-10-12T06:51:33-07:00"}

Publish Minio events via PostgreSQL

Install PostgreSQL database server. For illustrative purposes, we have set the "postgres" user password as password and created a database called minio_events to store the events.

This notification target supports two formats: namespace and access.

When the namespace format is used, Minio synchronizes objects in the bucket with rows in the table. It creates rows with two columns: key and value. The key is the bucket and object name of an object that exists in Minio. The value is JSON encoded event data about the operation that created/replaced the object in Minio. When objects are updated or deleted, the corresponding row from this table is updated or deleted respectively.

When the access format is used, Minio appends events to a table. It creates rows with two columns: event_time and event_data. The event_time is the time at which the event occurred in the Minio server. The event_data is the JSON encoded event data about the operation on an object. No rows are deleted or modified in this format.

The steps below show how to use this notification target in namespace format. The other format is very similar and is omitted for brevity.

Step 1: Add PostgreSQL endpoint to Minio

The default location of Minio server configuration file is ~/.minio/config.json. The PostgreSQL configuration is located in the postgresql key under the notify top-level key. Create a configuration key-value pair here for your PostgreSQL instance. The key is a name for your PostgreSQL endpoint, and the value is a collection of key-value parameters described in the table below.

Parameter Type Description
enable bool (Required) Is this server endpoint configuration active/enabled?
format string (Required) Either namespace or access.
connectionString string (Optional) Connection string parameters for the PostgreSQL server. Can be used to set sslmode for example.
table string (Required) Table name in which events will be stored/updated. If the table does not exist, the Minio server creates it at start-up.
host string (Optional) Host name of the PostgreSQL server. Defaults to localhost
port string (Optional) Port on which to connect to PostgreSQL server. Defaults to 5432.
user string (Optional) Database user name. Defaults to user running the server process.
password string (Optional) Database password.
database string (Optional) Database name.

An example of PostgreSQL configuration is as follows:

"postgresql": {
    "1": {
        "enable": true,
        "format": "namespace",
        "connectionString": "sslmode=disable",
        "table": "bucketevents",
        "host": "127.0.0.1",
        "port": "5432",
        "user": "postgres",
        "password": "password",
        "database": "minio_events"
    }
}

Note that for illustration here, we have disabled SSL. In the interest of security, for production this is not recommended.

After updating the configuration file, restart the Minio server to put the changes into effect. The server will print a line like SQS ARNs: arn:minio:sqs:us-east-1:1:postgresql at start-up if there were no errors.

Note that, you can add as many PostgreSQL server endpoint configurations as needed by providing an identifier (like "1" in the example above) for the PostgreSQL instance and an object of per-server configuration parameters.

Step 2: Enable bucket notification using Minio client

We will now enable bucket event notifications on a bucket named images. Whenever a JPEG image is created/overwritten, a new row is added or an existing row is updated in the PostgreSQL configured above. When an existing object is deleted, the corresponding row is deleted from the PostgreSQL table. Thus, the rows in the PostgreSQL table, reflect the .jpg objects in the images bucket.

To configure this bucket notification, we need the ARN printed by Minio in the previous step. Additional information about ARN is available here.

With the mc tool, the configuration is very simple to add. Let us say that the Minio server is aliased as myminio in our mc configuration. Execute the following:

# Create bucket named `images` in myminio
mc mb myminio/images
# Add notification configuration on the `images` bucket using the MySQL ARN. The --suffix argument filters events.
mc events add myminio/images arn:minio:sqs:us-east-1:1:postgresql --suffix .jpg
# Print out the notification configuration on the `images` bucket.
mc events list myminio/images
mc events list myminio/images
arn:minio:sqs:us-east-1:1:postgresql s3:ObjectCreated:*,s3:ObjectRemoved:* Filter: suffix=”.jpg”

Step 3: Test on PostgreSQL

Open another terminal and upload a JPEG image into images bucket.

mc cp myphoto.jpg myminio/images

Open PostgreSQL terminal to list the rows in the bucketevents table.

$ psql -h 127.0.0.1 -u postgres -p minio_events
minio_events=# select * from bucketevents;

key                 |                      value
--------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 images/myphoto.jpg | {"Records": [{"s3": {"bucket": {"arn": "arn:aws:s3:::images", "name": "images", "ownerIdentity": {"principalId": "minio"}}, "object": {"key": "myphoto.jpg", "eTag": "1d97bf45ecb37f7a7b699418070df08f", "size": 56060, "sequencer": "147CE57C70B31931"}, "configurationId": "Config", "s3SchemaVersion": "1.0"}, "awsRegion": "us-east-1", "eventName": "s3:ObjectCreated:Put", "eventTime": "2016-10-12T21:18:20Z", "eventSource": "aws:s3", "eventVersion": "2.0", "userIdentity": {"principalId": "minio"}, "responseElements": {}, "requestParameters": {"sourceIPAddress": "[::1]:39706"}}]}
(1 row)

Publish Minio events via MySQL

Install MySQL from here. For illustrative purposes, we have set the root password as password and created a database called miniodb to store the events.

This notification target supports two formats: namespace and access.

When the namespace format is used, Minio synchronizes objects in the bucket with rows in the table. It creates rows with two columns: key_name and value. The key_name is the bucket and object name of an object that exists in Minio. The value is JSON encoded event data about the operation that created/replaced the object in Minio. When objects are updated or deleted, the corresponding row from this table is updated or deleted respectively.

When the access format is used, Minio appends events to a table. It creates rows with two columns: event_time and event_data. The event_time is the time at which the event occurred in the Minio server. The event_data is the JSON encoded event data about the operation on an object. No rows are deleted or modified in this format.

The steps below show how to use this notification target in namespace format. The other format is very similar and is omitted for brevity.

Step 1: Add MySQL server endpoint configuration to Minio

The default location of Minio server configuration file is ~/.minio/config.json. The MySQL configuration is located in the mysql key under the notify top-level key. Create a configuration key-value pair here for your MySQL instance. The key is a name for your MySQL endpoint, and the value is a collection of key-value parameters described in the table below.

Parameter Type Description
enable bool (Required) Is this server endpoint configuration active/enabled?
format string (Required) Either namespace or access.
dsnString string (Optional) Data-Source-Name connection string for the MySQL server. If not specified, the connection information specified by the host, port, user, password and database parameters are used.
table string (Required) Table name in which events will be stored/updated. If the table does not exist, the Minio server creates it at start-up.
host string Host name of the MySQL server (used only if dsnString is empty).
port string Port on which to connect to the MySQL server (used only if dsnString is empty).
user string Database user-name (used only if dsnString is empty).
password string Database password (used only if dsnString is empty).
database string Database name (used only if dsnString is empty).

An example of MySQL configuration is as follows:

"mysql": {
        "1": {
                "enable": true,
                "dsnString": "",
                "table": "minio_images",
                "host": "172.17.0.1",
                "port": "3306",
                "user": "root",
                "password": "password",
                "database": "miniodb"
        }
}

After updating the configuration file, restart the Minio server to put the changes into effect. The server will print a line like SQS ARNs: arn:minio:sqs:us-east-1:1:mysql at start-up if there were no errors.

Note that, you can add as many MySQL server endpoint configurations as needed by providing an identifier (like "1" in the example above) for the MySQL instance and an object of per-server configuration parameters.

Step 2: Enable bucket notification using Minio client

We will now setup bucket notifications on a bucket named images. Whenever a JPEG image object is created/overwritten, a new row is added or an existing row is updated in the MySQL table configured above. When an existing object is deleted, the corresponding row is deleted from the MySQL table. Thus, the rows in the MySQL table, reflect the .jpg objects in the images bucket.

To configure this bucket notification, we need the ARN printed by Minio in the previous step. Additional information about ARN is available here.

With the mc tool, the configuration is very simple to add. Let us say that the Minio server is aliased as myminio in our mc configuration. Execute the following:

# Create bucket named `images` in myminio
mc mb myminio/images
# Add notification configuration on the `images` bucket using the MySQL ARN. The --suffix argument filters events.
mc events add myminio/images arn:minio:sqs:us-east-1:1:postgresql --suffix .jpg
# Print out the notification configuration on the `images` bucket.
mc events list myminio/images
arn:minio:sqs:us-east-1:1:postgresql s3:ObjectCreated:*,s3:ObjectRemoved:* Filter: suffix=”.jpg”

Step 3: Test on MySQL

Open another terminal and upload a JPEG image into images bucket:

mc cp myphoto.jpg myminio/images

Open MySQL terminal and list the rows in the minio_images table.

$ mysql -h 172.17.0.1 -P 3306 -u root -p miniodb
mysql> select * from minio_images;
+--------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| key_name           | value                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
+--------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| images/myphoto.jpg | {"Records": [{"s3": {"bucket": {"arn": "arn:aws:s3:::images", "name": "images", "ownerIdentity": {"principalId": "minio"}}, "object": {"key": "myphoto.jpg", "eTag": "467886be95c8ecfd71a2900e3f461b4f", "size": 26, "sequencer": "14AC59476F809FD3"}, "configurationId": "Config", "s3SchemaVersion": "1.0"}, "awsRegion": "us-east-1", "eventName": "s3:ObjectCreated:Put", "eventTime": "2017-03-16T11:29:00Z", "eventSource": "aws:s3", "eventVersion": "2.0", "userIdentity": {"principalId": "minio"}, "responseElements": {"x-amz-request-id": "14AC59476F809FD3", "x-minio-origin-endpoint": "http://192.168.86.110:9000"}, "requestParameters": {"sourceIPAddress": "127.0.0.1:38260"}}]} |
+--------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)

Publish Minio events via Kafka

Install kafka from here.

Step 1: Add kafka endpoint to Minio

The default location of Minio server configuration file is ~/.minio/config.json. Update the kafka configuration block in config.json as follows:

"kafka": {
    "1": {
        "enable": true,
        "brokers": ["localhost:9092"],
        "topic": "bucketevents"
    }
}

Restart Minio server to reflect config changes. bucketevents is the topic used by kafka in this example.

Step 2: Enable bucket notification using Minio client

We will enable bucket event notification to trigger whenever a JPEG image is uploaded or deleted from images bucket on myminio server. Here ARN value is arn:minio:sqs:us-east-1:1:kafka. To understand more about ARN please follow AWS ARN documentation.

mc mb myminio/images
mc events add  myminio/images arn:minio:sqs:us-east-1:1:kafka --suffix .jpg
mc events list myminio/images
arn:minio:sqs:us-east-1:1:kafka s3:ObjectCreated:*,s3:ObjectRemoved:* Filter: suffix=”.jpg”

Step 3: Test on kafka

We used kafkacat to print all notifications on the console.

kafkacat -C -b localhost:9092 -t bucketevents

Open another terminal and upload a JPEG image into images bucket.

mc cp myphoto.jpg myminio/images

kafkacat prints the event notification to the console.

kafkacat -b localhost:9092 -t bucketevents
{"EventType":"s3:ObjectCreated:Put","Key":"images/myphoto.jpg","Records":[{"eventVersion":"2.0","eventSource":"aws:s3","awsRegion":"us-east-1","eventTime":"2017-01-31T10:01:51Z","eventName":"s3:ObjectCreated:Put","userIdentity":{"principalId":"88QR09S7IOT4X1IBAQ9B"},"requestParameters":{"sourceIPAddress":"192.173.5.2:57904"},"responseElements":{"x-amz-request-id":"149ED2FD25589220","x-minio-origin-endpoint":"http://192.173.5.2:9000"},"s3":{"s3SchemaVersion":"1.0","configurationId":"Config","bucket":{"name":"images","ownerIdentity":{"principalId":"88QR09S7IOT4X1IBAQ9B"},"arn":"arn:aws:s3:::images"},"object":{"key":"myphoto.jpg","size":541596,"eTag":"04451d05b4faf4d62f3d538156115e2a","sequencer":"149ED2FD25589220"}}}],"level":"info","msg":"","time":"2017-01-31T15:31:51+05:30"}

Publish Minio events via Webhooks

Webhooks are a way to receive information when it happens, rather than continually polling for that data.

Step 1: Add Webhook endpoint to Minio

The default location of Minio server configuration file is ~/.minio/config.json. Update the Webhook configuration block in config.json as follows

"webhook": {
  "1": {
    "enable": true,
    "endpoint": "http://localhost:3000/"
}

Here the endpoint is the server listening for webhook notifications. Save the file and restart the Minio server for changes to take effect. Note that the endpoint needs to be live and reachable when you restart your Minio server.

Step 2: Enable bucket notification using Minio client

We will enable bucket event notification to trigger whenever a JPEG image is uploaded to images bucket on myminio server. Here ARN value is arn:minio:sqs:us-east-1:1:webhook. To learn more about ARN please follow AWS ARN documentation.

mc mb myminio/images
mc mb myminio/images-thumbnail
mc events add myminio/images arn:minio:sqs:us-east-1:1:webhook — events put — suffix .jpg

Check if event notification is successfully configured by

mc events list myminio/images

You should get a response like this

arn:minio:sqs:us-east-1:1:webhook   s3:ObjectCreated:*   Filter: suffix=".jpg"

Step 3: Test with Thumbnailer

We used Thumbnailer to listen for Minio notifications when a new JPEG file is uploaded (HTTP PUT). Triggered by a notification, Thumbnailer uploads a thumbnail of new image to Minio server. To start with, download and install Thumbnailer.

git clone https://github.com/minio/thumbnailer/
npm install

Then open the Thumbnailer config file at config/webhook.json and add the configuration for your Minio server and then start Thumbnailer by

NODE_ENV=webhook node thumbnail-webhook.js

Thumbnailer starts running at http://localhost:3000/. Next, configure the Minio server to send notifications to this URL (as mentioned in step 1) and use mc to set up bucket notifications (as mentioned in step 2). Then upload a JPEG image to Minio server by

mc cp ~/images.jpg myminio/images
.../images.jpg:  8.31 KB / 8.31 KB ┃▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓┃ 100.00% 59.42 KB/s 0s

Wait a few moments, then check the bucket’s contents with mc ls — you will see a thumbnail appear.

mc ls myminio/images-thumbnail
[2017-02-08 11:39:40 IST]   992B images-thumbnail.jpg

NOTE If you are running distributed Minio, modify ~/.minio/config.json on all the nodes with your bucket event notification backend configuration.