@milon-care/nsq-logger

nsq-logger

Nsq service to read messages from all topics listed within a list of nsqlookupd services.|

INFO: all examples are written in coffee-script

Install

  npm install nsq-logger

Initialize

var logger = new NsqLogger( config );

Example:

var NsqLogger = require( "nsq-logger" );

var config = {
    clientId: "myFooClient"
};

// create the logger
var logger = new NsqLogger( config );

// create a writer instance
/*
var NsqWriter = require( "nsq-logger/writer" );
var writer = new NsqLogger( config );
*/
// or just grab the one used inside the logger
var writer = logger.Writer;

logger.on( "message", function( topic, data, done ){
    // process your topic
    // Example response: -> topic="topic23" data ="Do some Stuff!"
    
    // mark message as done
    done();
});

writer.connect();
writer.publish( "topic23", "Do some Stuff!" );

Config

• clientId : ( String|Null required ) An identifier used to disambiguate this client.
• active : ( Boolean default=true ) Configuration to (en/dis)abel the nsq recorder
• namespace : ( String|Null default=null ) Internally prefix the nsq topics. This will be handled transparent, but with this it's possible to separate different environments from each other. E.g. you can run a "staging" and "live" environment on one nsq cluster.
• loggerChannel : ( String default="nsqlogger" ) The channel name for the logger to each topic
• exceededTopic : ( String default="_exceeded" ) A topic name, that will store exceeded messages.
• ignoreTopics : ( String[]|Function default=null ) A list of topics that should be ignored or a function that will called to check the ignored topics manually
• lookupdPollInterval : ( Number default=60 ) Time in seconds to poll the nsqlookupd servers to sync the available topics
• maxInFlight : ( Number default=1 ) The maximum number of messages to process at once. This value is shared between nsqd connections. It's highly recommended that this value is greater than the number of nsqd connections.
• heartbeatInterval : ( Number default=30 ) The frequency in seconds at which the nsqd will send heartbeats to this Reader.
• lookupdTCPAddresses : ( String[] default=[ "127.0.0.1:4160", "127.0.0.1:4162" ] ) A list of nsq lookup servers
• lookupdHTTPAddresses : ( String[] default=[ "127.0.0.1:4161", "127.0.0.1:4163" ] ) A list of nsq lookup servers
• maxAttempts : ( Number default=10 ) The number of times to a message can be requeued before it will be handed to the DISCARD handler and then automatically finished. 0 means that there is no limit. If not DISCARD handler is specified and maxAttempts > 0, then the message will be finished automatically when the number attempts has been exhausted.
• messageTimeout : ( Number|Null default=null ) Message timeout in ms or null for no timeout
• sampleRate : ( Number|Null default=null ) Deliver a percentage of all messages received to this connection. 1 <= sampleRate <= 99
• requeueDelay : ( Number|Null default=5 ) The delay is in seconds. This is how long nsqd will hold on the message before attempting it again.
• host : ( String default="127.0.0.1" ) Host of a nsqd
• port : ( Number default=4150 ) Port of a nsqd
• deflate : ( Boolean default=false ) Use zlib Deflate compression.
• deflateLevel : ( Number default=6 ) Use zlib Deflate compression level.

Methods

.activate()

Activate the module

Return

( Boolean ): true if it is now activated. false if it was already active

.deactivate()

Deactivate the module

Return

( Boolean ): true if it is now deactivated. false if it was already inactive

.active()

Test if the module is currently active

Return

( Boolean ): Is active?

.destroy( cb )

This will stop all readers and disconnect every connection from nsq

Arguments

• cb : ( Function ) Called after destroy

Events

message

The main event to catch and process messages from all topics.

Arguments

• topic : ( String ) The topic of this message
• data : ( String|Object|Array ) The message content. It tries to JSON.parse the message if possible. Otherwise it will be just a string.
• done : ( String ) You have to call this function until the message was processed. This will remove the message from the queue. Otherwise it will be requeued. If you add a argument cb( new Error("Dooh!") ) it will interpreted as an error and this message be requeued immediately

Example:

logger.on( "message", function( topic, data, done ){
    // process your message.
    // E.g: writing the data to a db with the topic as tablename
    myDB.write( "INSERT INTO " + topic + " VALUES ( " + data + " )", done );
});

ready

Emitted once the list of topics was received and the readers are created and connected. This is just an internal helper. The Method list will also wait for the first response. The events add, remove and change are active after this first response. Example:

topics.on( "ready", function( err ){
    // handle the error
});

Properties

logger.config

Type: ( Config )

This is the internaly used configuration.

Attributes

See logger config

logger.Writer

Type: ( NsqWriter )

To write messages you can use the internal writer instance.

Details see Writer

logger.Topics

Type: ( NsqTopics )

The logger uses a module called nsq-topics to sync the existing topics and generate the readers for each topic. You can grab the internal used insatnce with logger.Topics

Details see nsq-topics

logger.ready

Type: ( Boolean )

The logger is ready to use

---

Writer

Initialize

var NsqWriter = require( "nsq-logger/writer" )

Example:

var NsqWriter = require( "nsq-logger/writer" );

var config = {
    clientId: "myFooClient",
    host: "127.0.0.1",
    port: 4150
};

// create the writer
var writer = new NsqWriter( config );

writer.connect();
writer.publish( "topic23", "Do some Stuff!" );

Config

• clientId : ( String|Null required ) An identifier used to disambiguate this client.
• namespace : ( String|Null default=null ) Internally prefix the nsq topics. This will be handled transparent, but with this it's possible to separate different environments from each other. E.g. you can run a "staging" and "live" environment on one nsq cluster.
• active : ( Boolean default=true ) Configuration to (en/dis)abel the nsq recorder
• host : ( String default="127.0.0.1" ) Host of a nsqd
• port : ( Number default=4150 ) Port of a nsqd
• deflate : ( Boolean default=false ) Use zlib Deflate compression.
• deflateLevel : ( Number default=6 ) Use zlib Deflate compression level.

Methods

.connect()

You have to connect the writer before publishing data

Return

( Writer ): retuns itself for chaining

.disconnect()

disconnect the client

Return

( Writer ): retuns itself for chaining

.publish()

You have to connect the writer before publishing data

Arguments

• topic : ( String ) Topic name
• data : ( String|Object|Array ) Data to publish. If it's not a string it will be JSON stringified
• cb : ( Function ) Called after a successful publish

Return

( Writer ): retuns itself for chaining

Example:

writer
  .connect()
  .publish(
  	"hello", // the topic
  	JSON.strinigify( { to: [ "nsq-logger" ] } ) // the data to send
  );

.activate()

Activate the module

Return

( Boolean ): true if it is now activated. false if it was already active

.deactivate()

Deactivate the module

Return

( Boolean ): true if it is now deactivated. false if it was already inactive

.active()

Test if the module is currently active

Return

( Boolean ): Is active?

.destroy( cb )

Disconnect and remove all event listeners

Arguments

• cb : ( Function ) Called after destroy

Events

message

The main event to catch and process messages from all topics.

Arguments

• topic : ( String ) The topic of this message
• data : ( String|Object|Array ) The message content. A String or parsed JSON data.
• done : ( String ) You have to call this function until the message was processed. This will remove the message from the queue. Otherwise it will be requeued. If you add a argument cb( new Error("Dooh!") ) it will interpreted as an error and this message be requeued immediately
• msg : ( Message ) The raw nsqjs message.

Example:

logger.on( "message", function( topic, data, done ){
    // process your message.
    // E.g: writing the data to a db with the topic as tablename
    myDB.write( "INSERT INTO " + topic + " VALUES ( " + data + " )", done );
});

ready

Emitted once the list of topics was received and the readers are created and connected. This is just an internal helper. The Method list will also wait for the first response. The events add, remove and change are active after this first response. Example:

topics.on( "ready", function( err ){
    // handle the error
});

Properties

writer.ready

Type: ( Boolean )

The writer is ready to use

writer.connected

Type: ( Boolean )

The writer is connected to nsqd

---

Reader

Initialize

var NsqReader = require( "nsq-logger/reader" )
var reader = NsqReader( topic, channel, config )

Example:

var NsqReader = require( "nsq-logger/reader" );

var config = {
    clientId: "myFooClient",
    lookupdTCPAddresses: "127.0.0.1:4160",
    lookupdHTTPAddresses: "127.0.0.1: 4161",
};

// create the reader
var reader = new NsqReader( "topic23", "channel42", config );


reader.on( "message", function( topic, data, done ){
    // process your topic
    // Example response: -> data ="Do some Stuff!"
    
    // mark message as done
    done();
});
reader.connect();

Paramater

NsqReader( topic, channel, config )

• topic : ( String required ) The topic to listen to
• channel : ( String required ) The nsq channel to use or create
• config : ( Object|Config ) Configuration object or a config object

Config

• clientId : ( String|Null required ) An identifier used to disambiguate this client.
• namespace : ( String|Null default=null ) Internally prefix the nsq topics. This will be handled transparent, but with this it's possible to separate different environments from each other. E.g. you can run a "staging" and "live" environment on one nsq cluster.
• active : ( Boolean default=true ) Configuration to (en/dis)abel the nsq recorder
• maxInFlight : ( Number default=1 ) The maximum number of messages to process at once. This value is shared between nsqd connections. It's highly recommended that this value is greater than the number of nsqd connections.
• heartbeatInterval : ( Number default=30 ) The frequency in seconds at which the nsqd will send heartbeats to this Reader.
• lookupdTCPAddresses : ( String[] default=[ "127.0.0.1:4160", "127.0.0.1:4162" ] ) A list of nsq lookup servers
• lookupdHTTPAddresses : ( String[] default=[ "127.0.0.1:4161", "127.0.0.1:4163" ] ) A list of nsq lookup servers
• maxAttempts : ( Number default=10 ) The number of times to a message can be requeued before it will be handed to the DISCARD handler and then automatically finished. 0 means that there is no limit. If not DISCARD handler is specified and maxAttempts > 0, then the message will be finished automatically when the number attempts has been exhausted.
• messageTimeout : ( Number|Null default=null ) Message timeout in ms or null for no timeout
• sampleRate : ( Number|Null default=null ) Deliver a percentage of all messages received to this connection. 1 <= sampleRate <= 99
• requeueDelay : ( Number|Null default=5 ) The delay is in seconds. This is how long nsqd will hold on the message before attempting it again.

Methods

.connect()

You have to connect the writer before publishing data

Return

( Writer ): retuns itself for chaining

.disconnect()

disconnect the client

Return

( Writer ): retuns itself for chaining

.activate()

Activate the module

Return

( Boolean ): true if it is now activated. false if it was already active

.deactivate()

Deactivate the module

Return

( Boolean ): true if it is now deactivated. false if it was already inactive

.active()

Test if the module is currently active

Return

( Boolean ): Is active?

.destroy( cb )

Disconnect and remove all event listeners

Arguments

• cb : ( Function ) Called after destroy

Events

message

The main event to catch and process messages from the defined topic.

Arguments

• data : ( String|Object|Array ) The message content. A String or parsed JSON data.
• done : ( String ) You have to call this function until the message was processed. This will remove the message from the queue. Otherwise it will be requeued. If you add a argument cb( new Error("Dooh!") ) it will interpreted as an error and this message be requeued immediately

Example:

logger.on( "message", function( data, done ){
    // process your message.
    // E.g: writing the data to a db
    myDB.write( "INSERT INTO mylogs VALUES ( " + data + " )", done );
});

ready

Emitted once the list of topics was received and the readers are created and connected. This is just an internal helper. The Method list will also wait for the first response. The events add, remove and change are active after this first response. Example:

topics.on( "ready", function( err ){
    // handle the error
});

Properties

writer.ready

Type: ( Boolean )

The writer is ready to use

writer.connected

Type: ( Boolean )

The writer is connected to nsqd

---

TODO's / IDEAS

• more tests
• use with promises

Release History

Version	Date	Description
1.0.0	2019-01-08	Make the module compatible with node:10 but no longer compatible with node < 5
0.1.3	2017-07-25	Small fix to catch JSON stringify errors within Writer.publish
0.1.2	2016-07-22	Fixed a stupid error with the host config of the writer
0.1.1	2016-07-19	Removed debugging output
0.1.0	2016-07-15	Updated dependencies Issue#2 and optimized activate Issue#3
0.0.7	2016-01-20	Added raw nsqjs Message as last argument to the message event
0.0.6	2015-12-04	Bugfix on setting an array configuration; added code banner
0.0.5	2015-12-03	Added namespaces and made multiple parallel logger instances possible.
0.0.4	2015-12-03	configuration bugfix
0.0.3	2015-12-02	updated object tests
0.0.2	2015-12-02	Internal restructure and docs
0.0.1	2015-12-02	Initial version

Initially Generated with generator-mpnodemodule

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The MIT License (MIT)

Copyright © 2015 M. Peter, 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.