rsmq

A really simple message queue based on Redis

Redis Simple Message Queue

A lightweight message queue for Node.js that requires no dedicated queue server. Just a Redis server.

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 Node.js processes can send / receive messages.

Features

• Lightweight: Just Redis and ~500 lines of javascript.
• Guaranteed delivery of a message to exactly one recipient within a messages visibility timeout.
• Received messages that are not deleted will reappear after the visibility timeout.
• Test coverage
• Similar to Amazon SQS - with some differences:
  • No ReceiptHandle. A message is deleted by the message id. The message id is returned by the sendMessage and receiveMessage method.
  • No MessageRetentionPeriod: Messages stay in the queue unless deleted.
  • No bulk operations (SendMessageBatch, DeleteMessageBatch).
  • Some SQS 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 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

s

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 be 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.

setQueueAttributes

Sets queue parameters.

Parameters:

• qname (String): The Queue name.
• vt (Number): optional * 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 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 The maximum message size in bytes. Allowed values: 1024-65536

Note: At least one attribute (vt, delay, maxsize) must be supplied. Only attributes that are supplied will be modified.

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 be hidden while "in flight" due to a vt parameter or when sent with a delay

quit

Disconnect the redis client. This is only useful if you are using rsmq within a script and want node to be able to exit.

Changes

see the CHANGELOG

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The MIT License (MIT)

Copyright © 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.

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