RSMQ helper to simply implement a worker around the message queue
npm install rsmq-worker
Helper to simply implement a worker RSMQ ( Redis Simple Message Queue ).
> :warning: Note: RSMQ uses the Redis EVAL command (LUA scripts) so the minimum Redis version is 2.6+.
``sh`
npm install rsmq-worker
`js`
new RSMQWorker( queuename, options );
Example:
`js
var RSMQWorker = require( "rsmq-worker" );
var worker = new RSMQWorker( "myqueue" );
worker.on( "message", function( msg, next, id ){
// process your message
console.log("Message id : " + id);
console.log(msg);
next()
});
// optional error listeners
worker.on('error', function( err, msg ){
console.log( "ERROR", err, msg.id );
});
worker.on('exceeded', function( msg ){
console.log( "EXCEEDED", msg.id );
});
worker.on('timeout', function( msg ){
console.log( "TIMEOUT", msg.id, msg.rc );
});
worker.start();
`
Config
- queuename: ( String required ) The queuename to pull the messages
- options ( Object optional ) The configuration object
- options.interval: ( Number[] optional; default = [ 0, 1, 5, 10 ] ) An Array of increasing wait times in seconds
- options.maxReceiveCount: ( Number optional; default = 10 ) Receive count until a message will be exceeded
- options.invisibletime: ( Number optional; default = 30 ) A time in seconds to hide a message after it has been received.
- options.defaultDelay: ( Number optional; default = 1 ) The default delay in seconds for for sending new messages to the queue.
- options.autostart: ( Boolean optional; default = false ) Autostart the worker on init
- options.timeout: ( Number optional; default = 3000 ) Message processing timeout in ms. So you have to call the next() method of message at least after e.g. 3000ms. If set to 0 it'll wait until infinity.Function
- options.customExceedCheck: ( optional; ) A custom function, with the raw message (see message format) as argument to build a custom exceed check. If you return a true the message will not exceed. On return false the regular check for maxReceiveCount will be used.Boolean
- options.alwaysLogErrors: ( optional; default = false ) An error will be logged to the console even if an error listener has been attached.RedisSMQ
- options.rsmq: ( optional; default = null ) A already existing rsmq instance to use instead of creating a new clientRedisClient
- options.redis: ( optional; default = null ) A already existing redis client instance to use if no rsmq instance has been defined String
- options.redisPrefix: ( optional; default = "" ) The redis prefix/namespace for rsmq if no rsmq instance has been defined. This has to match the option ns of RSMQ.String
- options.host: ( optional; default = "localhost" ) Host to connect to redis if no rsmq or redis instance has been defined Number
- options.port: ( optional; default = 6379 ) Port to connect to redis if no rsmq or redis instance has been defined Object
- options.options: ( optional; default = {} ) Options to connect to redis if no rsmq or redis instance has been defined
A message ( e.g. received by the event data or customExceedCheck ) contains the following keys:
- msg.message : ( String ) The queue message content. You can use complex content by using a stringified JSON.
- msg.id : ( String ) The rsmq internal message id
- msg.sent : ( Number ) Timestamp of when this message was sent / created.
- msg.fr : ( Number ) Timestamp of when this message was first received.
- msg.rc : ( Number ) Number of times this message was received.
If you haven't defined the config autostart to true you have to call the .start() method.
Return
( Self ): The instance itself for chaining.
Just stop the receive interval.
This will not cut the connection to rsmq/redis.
If you want you script to end call .quit()
Return
( Self ): The instance itself for chaining.
Helper function to simply send a message in the configured queue.
Arguments
msg : ( String required )*: The rsmq message. In best practice it's a stringified JSON with additional data.delay
: ( Number optional; default = 0 )*: The message delay to hide this message for the next x seconds.cb
: ( Function optional )*: An optional callback to get a secure response for a successful send.
Return
( Self ): The instance itself for chaining.
Helper function to simply delete a message after it has been processed.
Arguments
id : ( String required )*: The rsmq message id.cb
: ( Function optional )*: A optional callback to get a secure response for a successful delete.
Return
( Self ): The instance itself for chaining.
Change the interval timeouts in operation.
Arguments
interval : ( Number|Array required )*: The new interval.
Return
( Self ): The instance itself for chaining.
Stop the worker and close the connection.
After this it's no longer possible to reuse the worker-instance.
It's just intended to kill all timers and connections so your script will end.
Get the current queue attributes.
This is just a shortcut to the rsmq.getQueueAttributes.
Arguments
cb : ( Function )*: Callback with ( err, attributes ). See rsmq-docs for details.
Get the current queue size.
Arguments
hidden : ( Boolean optional; default = false )*: The count of messages including the currently hidden/"in flight" messages.cb
: ( Function optional )*: Callback with ( err, size ). The size is a Number and repersents the number of messages in the queue. If hidden=true you will receive the numebr of currently hidden messages
Return
( Self ): The instance itself for chaining.
Main event to catch and process a message.
If you do not set a handler for this Event nothing will happen.
Example:
`js`
worker.on( "message", function( message, next, msgid ){
// process message ...
next();
});
Arguments
- message : ( String ) The queue message content to process. You can use complex content by using a stringified JSON.
- next : ( Function ) A function you have to call when your message has been processed.
Arguments
delete: ( Boolean|Error optional; default = true )* Error: If you return an error it will emitted as an error event; Boolean: It's possible to prevent the worker from auto-delete the message on end. This is useful if you want to pop up a message multiple times. To implement this, please check the config options.customExceedCheck
- msgid : ( ) The message id. This is useful if you want to delete a message manually.
Fired until the worker is connected to rsmq/redis and has been initialized with the given queuename.
The raw event when a message has been received.
Arguments
- msg : ( String ) The raw rsmq message. ( See section Raw message format )
Fired after a message has been deleted.
Arguments
- id : ( String ) The rsmq message id
Fired after a message has been exceeded and immediately will be deleted.
Arguments
- msg : ( String ) The raw rsmq message. ( See section Raw message format )
Fired if a message processing exceeds the configured timeout.
Arguments
- msg : ( String ) The raw rsmq message. ( See section Raw message format )
Fired if a message processing throws an error.
Arguments
- err : ( Error|Any ) The thrown error
- msg : ( String ) The raw rsmq message. ( See section Raw message format )
This is an advanced example showing some features in action.
`js
var fs = require( "fs" );
var RSMQWorker = require( "rsmq-worker" );
var fnCheck = function( msg ){
// check function to not exceed the message if the content is createmessages
if( msg.message === "createmessages" ){
return true
}
return false
}
var worker = new RSMQWorker( "myqueue", {
interval: [ .1, 1 ], // wait 100ms between every receive and step up to 1,3 on empty receives
invisibletime: 2, // hide received message for 5 sec
maxReceiveCount: 2, // only receive a message 2 times until delete
autostart: true, // start worker on init
customExceedCheck: fnCheck // set the custom exceed check
});
// Listen to errors
worker.on('error', function( err, msg ){
console.log( "ERROR", err, msg.id );
});
worker.on('timeout', function( msg ){
console.log( "TIMEOUT", msg.id, msg.rc );
});
// handle exceeded messages
// grab the internal rsmq instance
var rsmq = worker._getRsmq();
worker.on('exceeded', function( msg ){
console.log( "EXCEEDED", msg.id );
// NOTE: make sure this queue exists
rsmq.sendMessage( "YOUR_EXCEEDED_QUEUE", msq, function( err, resp ){
if( err ){
console.error( "write-to-exceeded-queue", err )
}
});
});
// listen to messages
worker.on( "message", function( message, next, id ){
console.log( "message", message );
if( message === "createmessages" ){
next( false )
worker.send( JSON.stringify( { type: "writefile", filename: "./test.txt", txt: "Foo Bar" } ) );
worker.send( JSON.stringify( { type: "deletefile", filename: "./test.txt" } ) );
return
}
var _data = JSON.parse( message )
switch( _data.type ){
case "writefile":
fs.writeFile( _data.filename, _data.txt, function( err ){
if( err ){
next( err );
}else{
next()
}
});
break;
case "deletefile":
fs.unlink( _data.filename, function( err ){
if( err ){
next( err );
}else{
next()
}
});
break;
}
});
worker.send( "createmessages" );
`
- MORE tests!
- Optional parallel execution. To do multiple receives in parallel.
- Automatic write of exceeded messages to a configured queue.
(Issue#17) and .size( [hidden,] cb )|
|0.4.3|2016-06-20|Optimized event listeners Issue#15. Thanks to Kevin Turner|
|0.4.2|2016-05-06|Added the .quit() function Issue#11. Thanks to Sam Fung|
|0.4.1|2016-04-05|Fixed missing isNumber function|
|0.4.0|2016-03-30|Updated dependencies (especially lodash to 4.x). Fixed a config bug caused by the array merge from extend Issue#7. Thanks to Peter Hanneman|
|0.3.8|2015-11-04|Fixed stop behavior. Pull#5. Thanks to Exinferis|
|0.3.7|2015-09-02|Added tests to check the behavior during errors within message processing; Added option alwaysLogErrors to prevent console logs if an error event handler was attached. Issue #3|
|0.3.6|2015-09-02|Updated dependencies; optimized readme (thanks to Tobias Lidskog for the pull #4)|
|0.3.5|2015-04-27|again ... fixed argument dispatch for .send()|
|0.3.4|2015-04-27|fixed argument dispatch for .send() and added optional cb for .del()|
|0.3.3|2015-03-27|added changeInterval to modify the interval in operation|
|0.3.2|2015-02-23|changed default prefix/namespace;|
|0.3.0|2015-02-16|It's now possible to return an error as first argument of next. This will lead to an error emit + optimized readme|
|0.2.2|2015-01-27|added option defaultDelay and optimized arguments of the send` method; fixed travis.yml|
> Initially Generated with generator-mpnodemodule
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|redis-notifications|A redis based notification engine. It implements the rsmq-worker to safely create notifications and recurring reports.|
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|systemhealth|Node module to run simple custom checks for your machine or it's connections. It will use redis-heartbeat to send the current state to redis.|
|task-queue-worker|A powerful tool for background processing of tasks that are run by making standard http requests.|
|soyer|Soyer is small lib for serverside use of Google Closure Templates with node.js.|
|grunt-soy-compile|Compile Goggle Closure Templates ( SOY ) templates inclding the handling of XLIFF language files.|
|backlunr|A solution to bring Backbone Collections together with the browser fulltext search engine Lunr.js|
Copyright © 2015 Mathias Peter, http://www.tcs.de
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