rsmq

rsmq

A really simple message queue based on Redis

tl;dr: If you run a Redis server and currently use Amazon SQS or a similar message queue you might as well use this fast little replacement. Using a shared Redis server multiple NodeJS processes can send / receive messages. The receiveMessage Method uses a Redis Lua script to ensure a message is only delivered to a single recipient.

Features

• Lightweight: Just Redis. Every client can send and receive messages via a shared Redis server.

• Guaranteed delivery of a message to exactly one recipient within a messages visibility timeout.

• No security: Like memcached. Only for internal use in trusted environments.

• Test coverage

• Similar to Amazon SQS (Simple Queue Service) - with some differences:

  • Durability depends on your Redis setup.
  • No ReceiptHandle. A message is deleted by the message id. A message can be deleted if you store the id that is returned from the sendMessage method.
  • No MessageRetentionPeriod: Messages stay in the queue unless deleted.
  • No bulk operations (SendMessageBatch, DeleteMessageBatch)
  • Some AWS specific features are missing

• Optional RESTful interface via rest-rsmq

Usage

• After creating a queue you can send messages to that queue.
• The messages will be handled in a FIFO (first in first out) manner unless specified differently with a delay.
• Every message has a unique id that you can use to delete the message.
• The sendMessage method will return the id for a sent message.
• The receiveMessage method will return an id along with the message and some stats.
• Should you not delete the message it will be eligible to be received again after the visibility timeout is reached.
• Please have a look at the createQueue and receiveMessage methods described below for optional parameters like visibility timeout and delay.

Installation

npm install rsmq

Example

Initialize

RedisSMQ = require("rsmq");
rsmq = new RedisSMQ( {host: "127.0.0.1", port: 6379, ns: "rsmq"} );

Parameters for RedisSMQ via an options object:

• host (String): optional (Default: "127.0.0.1") The Redis server
• port (Number): optional (Default: 6379) The Redis port
• options (Object): optional (Default: {}) The Redis https://github.com/mranney/node_redis#rediscreateclientport-host-options options object.
• client (RedisClient): optional A existing redis client instance. host and server will be ignored.
• ns (String): optional (Default: "rsmq") The namespace prefix used for all keys created by rsmq

Create a queue

Please look at the Methods section for optional parameters when creating a queue.

rsmq.createQueue({qname:"myqueue"}, function (err, resp) {
		if (resp===1) {
			console.log("queue created")
		}
});

Send a message

rsmq.sendMessage({qname:"myqueue", message:"Hello World"}, function (err, resp) {
	if (resp) {
		console.log("Message sent. ID:", resp);
	}
});

Receive a message

rsmq.receiveMessage({qname:"myqueue"}, function (err, resp) {
	if (resp.id) {
		console.log("Message received.", resp)	
	}
	else {
		console.log("No messages for me...")
	}
});

Delete a message

rsmq.deleteMessage({qname:"myqueue", id:"dhoiwpiirm15ce77305a5c3a3b0f230c6e20f09b55"}, function (err, resp) {
	if (resp===1) {
		console.log("Message deleted.")	
	}
	else {
		console.log("Message not found.")
	}
});

Methods

changeMessageVisibility

Change the visibility timer of a single message. The time when the message will be visible again is calculated from the current time (now) + vt.

Parameters:

• qname (String): The Queue name.
• id (String): The message id.
• vt (Number): The length of time, in seconds, that this message will not be visible. Allowed values: 0-9999999 (around 115 days)

Returns:

• 1 if successful, 0 if the message was not found.

createQueue

Create a new queue.

Parameters:

• qname (String): The Queue name. Maximum 80 characters; alphanumeric characters, hyphens (-), and underscores (_) are allowed.
• vt (Number): optional (Default: 30) The length of time, in seconds, that a message received from a queue will be invisible to other receiving components when they ask to receive messages. Allowed values: 0-9999999 (around 115 days)
• delay (Number): optional (Default: 0) The time in seconds that the delivery of all new messages in the queue will be delayed. Allowed values: 0-9999999 (around 115 days)
• maxsize (Number): optional (Default: 65536) The maximum message size in bytes. Allowed values: 1024-65536

Returns:

• 1

deleteMessage

Parameters:

• qname (String): The Queue name.
• id (String): message id to delete.

Returns:

• 1 if successful, 0 if the message was not found.

deleteQueue

Deletes a queue and all messages.

Parameters:

• qname (String): The Queue name.

Returns:

• 1

getQueueAttributes

Get queue attributes, counter and stats

Parameters:

• qname (String): The Queue name.

Returns an object:

• vt: The visibility timeout for the queue in seconds
• delay: The delay for new messages in seconds
• maxsize: The maximum size of a message in bytes
• totalrecv: Total number of messages received from the queue
• totalsent: Total number of messages sent to the queue
• created: Timestamp (epoch in seconds) when the queue was created
• modified: Timestamp (epoch in seconds) when the queue was last modified with setQueueAttributes
• msgs: Current number of messages in the queue
• hiddenmsgs: Current number of hidden / not visible messages. A message can hidden while "in flight" due to a vt parameter or when sent with a delay

listQueues

List all queues

Returns an array:

• ["qname1", "qname2"]

receiveMessage

Receive the next message from the queue.

Parameters:

• qname (String): The Queue name.
• vt (Number): optional (Default: queue settings) The length of time, in seconds, that the received message will be invisible to others. Allowed values: 0-9999999 (around 115 days)

Returns an object:

• message: The message's contents.
• id: The internal message id.
• sent: Timestamp of when this message was sent / created.
• fr: Timestamp of when this message was first received.
• rc: Number of times this message was received.

Note: Will return an empty object if no message is there

sendMessage

Sends a new message.

Parameters:

• qname (String)
• message (String)
• delay (Number): optional (Default: queue settings) The time in seconds that the delivery of the message will be delayed. Allowed values: 0-9999999 (around 115 days)

Returns:

• id: The internal message id.

Not implemented yet

setQueueAttributes

Sets queue parameters.

Changes

see the CHANGELOG

The MIT License (MIT)

Copyright © 2013 Patrick Liess, http://www.tcs.de

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Changelog

0.3.4

• Added support for https://github.com/mranney/node_redis#rediscreateclientport-host-options options object.