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RocketMQ

Detailed documentation on the RocketMQ pubsub component

Component format

To set up RocketMQ pub/sub, create a component of type pubsub.rocketmq. See the pub/sub broker component file to learn how ConsumerID is automatically generated. Read the How-to: Publish and Subscribe guide on how to create and apply a pub/sub configuration.

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: rocketmq-pubsub
spec:
  type: pubsub.rocketmq
  version: v1
  metadata:
    - name: instanceName
      value: dapr-rocketmq-test
    - name: consumerGroup
      value: dapr-rocketmq-test-g-c
    - name: producerGroup 
      value: dapr-rocketmq-test-g-p
    - name: consumerID
      value: topic
    - name: nameSpace
      value: dapr-test
    - name: nameServer
      value: "127.0.0.1:9876,127.0.0.2:9876"
    - name: retries
      value: 3
    - name: consumerModel
      value: "clustering"
    - name: consumeOrderly
      value: false

Spec metadata fields

Field Required Details default Example
instanceName N Instance name time.Now().String() dapr-rocketmq-test
consumerGroup N Consumer group name. Recommend. If producerGroup is null，groupName is used. dapr-rocketmq-test-g-c
producerGroup (consumerID) N Producer group name. Recommended. If producerGroup is null，consumerID is used. If consumerID also is null, groupName is used. dapr-rocketmq-test-g-p
consumerID N Consumer ID (consumer tag) organizes one or more consumers into a group. Consumers with the same consumer ID work as one virtual consumer; for example, a message is processed only once by one of the consumers in the group. If the consumerID is not provided, the Dapr runtime set it to the Dapr application ID (appID) value. "channel1"
groupName N Consumer/Producer group name. Depreciated. dapr-rocketmq-test-g
nameSpace N RocketMQ namespace dapr-rocketmq
nameServerDomain N RocketMQ name server domain https://my-app.net:8080/nsaddr
nameServer N RocketMQ name server, separated by “,” or “;” 127.0.0.1:9876;127.0.0.2:9877,127.0.0.3:9877
accessKey N Access Key (Username) "admin"
secretKey N Secret Key (Password) "password"
securityToken N Security Token
retries N Number of retries to send a message to broker 3 3
producerQueueSelector (queueSelector) N Producer Queue selector. There are five implementations of queue selector: hash, random, manual, roundRobin, dapr. dapr hash
consumerModel N Message model that defines how messages are delivered to each consumer client. RocketMQ supports two message models: clustering and broadcasting. clustering broadcasting , clustering
fromWhere (consumeFromWhere) N Consuming point on consumer booting. There are three consuming points: CONSUME_FROM_LAST_OFFSET, CONSUME_FROM_FIRST_OFFSET, CONSUME_FROM_TIMESTAMP CONSUME_FROM_LAST_OFFSET CONSUME_FROM_LAST_OFFSET
consumeTimestamp N Backtracks consumption time with second precision. Time format is yyyymmddhhmmss. For example, 20131223171201 implies the time of 17:12:01 and date of December 23, 2013 time.Now().Add(time.Minute * (-30)).Format("20060102150405") 20131223171201
consumeOrderly N Determines if it’s an ordered message using FIFO order. false false
consumeMessageBatchMaxSize N Batch consumption size out of range [1, 1024] 512 10
consumeConcurrentlyMaxSpan N Concurrently max span offset. This has no effect on sequential consumption. Range: [1, 65535] 1000 1000
maxReconsumeTimes N Max re-consume times. -1 means 16 times. If messages are re-consumed more than {@link maxReconsumeTimes} before success, they’ll be directed to a deletion queue. Orderly message is MaxInt32; Concurrently message is 16 16
autoCommit N Enable auto commit true false
consumeTimeout N Maximum amount of time a message may block the consuming thread. Time unit: Minute 15 15
consumerPullTimeout N The socket timeout in milliseconds
pullInterval N Message pull interval 100 100
pullBatchSize N The number of messages pulled from the broker at a time. If pullBatchSize is null, use ConsumerBatchSize. pullBatchSize out of range [1, 1024] 32 10
pullThresholdForQueue N Flow control threshold on queue level. Each message queue will cache a maximum of 1000 messages by default. Consider the PullBatchSize - the instantaneous value may exceed the limit. Range: [1, 65535] 1024 1000
pullThresholdForTopic N Flow control threshold on topic level. The value of pullThresholdForQueue will be overwritten and calculated based on pullThresholdForTopic if it isn’t unlimited. For example, if the value of pullThresholdForTopic is 1000 and 10 message queues are assigned to this consumer, then pullThresholdForQueue will be set to 100. Range: [1, 6553500] -1(Unlimited) 10
pullThresholdSizeForQueue N Limit the cached message size on queue level. Consider the pullBatchSize - the instantaneous value may exceed the limit. The size of a message is only measured by message body, so it’s not accurate. Range: [1, 1024] 100 100
pullThresholdSizeForTopic N Limit the cached message size on topic level. The value of pullThresholdSizeForQueue will be overwritten and calculated based on pullThresholdSizeForTopic if it isn’t unlimited. For example, if the value of pullThresholdSizeForTopic is 1000 MiB and 10 message queues are assigned to this consumer, then pullThresholdSizeForQueue will be set to 100 MiB. Range: [1, 102400] -1 100
content-type N Message content type. "text/plain" "application/cloudevents+json; charset=utf-8", "application/octet-stream"
logLevel N Log level warn info
sendTimeOut N Send message timeout to connect RocketMQ’s broker, measured in nanoseconds. Deprecated. 3 seconds 10000000000
sendTimeOutSec N Timeout duration for publishing a message in seconds. If sendTimeOutSec is null, sendTimeOut is used. 3 seconds 3
mspProperties N The RocketMQ message properties in this collection are passed to the APP in Data Separate multiple properties with “,” key,mkey

For backwards-compatibility reasons, the following values in the metadata are supported, although their use is discouraged.

Field (supported but deprecated) Required Details Example
groupName N Producer group name for RocketMQ publishers "my_unique_group_name"
sendTimeOut N Timeout duration for publishing a message in nanoseconds 0
consumerBatchSize N The number of messages pulled from the broker at a time 32

Setup RocketMQ

See https://rocketmq.apache.org/docs/quick-start/ to setup a local RocketMQ instance.

Per-call metadata fields

Partition Key

When invoking the RocketMQ pub/sub, it’s possible to provide an optional partition key by using the metadata query param in the request url.

You need to specify rocketmq-tag , "rocketmq-key" , rocketmq-shardingkey , rocketmq-queue in metadata

Example:

curl -X POST http://localhost:3500/v1.0/publish/myRocketMQ/myTopic?metadata.rocketmq-tag=?&metadata.rocketmq-key=?&metadata.rocketmq-shardingkey=key&metadata.rocketmq-queue=1 \
  -H "Content-Type: application/json" \
  -d '{
        "data": {
          "message": "Hi"
        }
      }'

QueueSelector

The RocketMQ component contains a total of five queue selectors. The RocketMQ client provides the following queue selectors:

  • HashQueueSelector
  • RandomQueueSelector
  • RoundRobinQueueSelector
  • ManualQueueSelector

To learn more about these RocketMQ client queue selectors, read the RocketMQ documentation.

The Dapr RocketMQ component implements the following queue selector:

  • DaprQueueSelector

This article focuses on the design of DaprQueueSelector.

DaprQueueSelector

DaprQueueSelector integrates three queue selectors:

  • HashQueueSelector
  • RoundRobinQueueSelector
  • ManualQueueSelector

DaprQueueSelector gets the queue id from the request parameter. You can set the queue id by running the following:

http://localhost:3500/v1.0/publish/myRocketMQ/myTopic?metadata.rocketmq-queue=1

The ManualQueueSelector is implemented using the method above.

Next, the DaprQueueSelector tries to:

  • Get a ShardingKey
  • Hash the ShardingKey to determine the queue id.

You can set the ShardingKey by doing the following:

http://localhost:3500/v1.0/publish/myRocketMQ/myTopic?metadata.rocketmq-shardingkey=key

If the ShardingKey does not exist, the RoundRobin algorithm is used to determine the queue id.