Grouper messaging built in
Grouper has a built in messaging system which is not as robust as a messaging middleware product such as ActiveMQ or RabbitMQ.
A message is just a record in a database table which has a timestamp (which determines the ordering), and other fields.
A sender can send to a queue or a topic. A queue has a receiver pulling messages. A topic will just distribute to 1 or more queues.
Receivers need to receive the message then mark it as processed when done.
Message table: grouper_message: If using the default internal messaging with Grouper, this is the table that holds the messages and state of messages
See Grouper Messaging System Developers Guide for info on how to integrate the Grouper Messaging System with another messaging system.
Setup queues
Queues can be sent to directly or from topics
A queue shouldnt have the same name as a topic.
There is a built in folder for queues in grouper: <ATTRIBUTE_ROOT_STEM_CONFIGURED_NAME>:grouperMessageQueues.
A queue is a permission resource in that folder of attributeDef <ATTRIBUTE_ROOT_STEM_CONFIGURED_NAME>:messages:grouperMessageQueueDef
The action to send to a topic is "send_to_queue", grant that to a subject who is allowed to send messages to the queue
The action to receive from a queue is "receive", grant that to a subject who is allowed to pull messages off the queue
grouperSession = GrouperSession.startRootSession();
GrouperBuiltinMessagingSystem.createQueue("abc");
GrouperBuiltinMessagingSystem.deleteQueue("abc");
// permissions on objects
GrouperBuiltinMessagingSystem.allowSendToQueue("abc", SubjectTestHelper.SUBJ0);
GrouperBuiltinMessagingSystem.allowReceiveFromQueue("abc", SubjectTestHelper.SUBJ0);
GrouperBuiltinMessagingSystem.disallowSendToQueue("abc", SubjectTestHelper.SUBJ0);
GrouperBuiltinMessagingSystem.disallowReceiveFromQueue("abc", SubjectTestHelper.SUBJ0);
Setup topics
There is a built in folder for topics in grouper: <ATTRIBUTE_ROOT_STEM_CONFIGURED_NAME>:grouperMessageTopics.
A topic is a permission resource in that folder of attributeDef <ATTRIBUTE_ROOT_STEM_CONFIGURED_NAME>:messages:grouperMessageTopicDef
The action to send to a topic is "send_to_topic", grant that to a subject who is allowed to send messages to the topic
You cannot read from a topic, the topic will send to queues, and you can grant that on queues
To setup the relationship between a topic and queue(s), setup a permission resource implied relationship between the topic and the queues
grouperSession = GrouperSession.startRootSession();
GrouperBuiltinMessagingSystem.createTopic("def");
GrouperBuiltinMessagingSystem.deleteTopic("def");
// permissions on objects
GrouperBuiltinMessagingSystem.allowSendToTopic("abc", SubjectTestHelper.SUBJ0);
GrouperBuiltinMessagingSystem.disallowSendToTopic("abc", SubjectTestHelper.SUBJ0);
// topics send to queues
GrouperBuiltinMessagingSystem.topicAddSendToQueue("def", "abc");
Collection<String> queues = GrouperBuiltinMessagingSystem.queuesTopicSendsTo("def");
GrouperBuiltinMessagingSystem.topicRemoveSendToQueue("def", "abc");Performance
This system (with local HSQL database) can process (send / receive / acknowledge)
125 messages per second in one thread
312 messages per second in 10 threads
Message columns
Column name | Description | Index | Foreign key |
|---|---|---|---|
ID | db uuid for this row |
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HIBERNATE_VERSION_NUMBER | incrementing number so two updates dont occur at once (optimistic locking) |
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SENT_TIME_MICROS | microseconds since 1970 this message was sent (note this is unique for one jvm, this is probably unique across jvms, but not necessarily) |
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GET_ATTEMPT_TIME_MILLIS | milliseconds that the message was attempted to be received. If the message is not confirmed in a certain amount of time, the state will be set back to IN_QUEUE to try again |
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GET_ATTEMPT_COUNT | how many times this message has been attempted to be retrieved |
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STATE | state of this message: IN_QUEUE, GET_ATTEMPTED, PROCESSED |
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GET_TIME_MILLIS | millis since 1970 that this message was successfully received |
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FROM_MEMBER_ID | member id of user who sent the message |
| foreign key to grouper_members.id |
QUEUE_NAME | queue name for the message that it is delivered to (note, topics can send to multiple queues, which will duplicate the message) |
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MESSAGE_BODY | message body |
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ATTEMPT_TIME_EXPIRES_MILLIS | millis since 1970 that this attempt will expire before it is acknowledged. After it expires it will be delivered again when receive() is called |
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See Also:
Message Format Detail
Message Format Config Example