nsq-nodes

Nsq helper to poll a nsqlookupd service for all it's nodes and mirror it locally.

INFO: all examples are written in coffee-script

Install

  npm install nsq-nodes

Initialize

new NsqNodes( config );

Example:

var NsqNodes = require( "nsq-nodes" )

var nodes = new NsqNodes({
    // Listen to two local nsq lookupservers
    "lookupdHTTPAddresses": [ "127.0.0.1:4161", "127.0.0.1:4163" ]
});

// get the current list of nodes
nodes.list( function( err, nodes ){
    if( err ){
        // handle the error
    }
    console.log( nodes ) // -> an array of nodes. E.g.: ( )`users`, `logins`, ... )


    // listen for new nodes
    nodes.on( "add", function( node ){
        // called until a new node arrived
    });

    // listen for removed nodes
    nodes.on( "remove", function( node ){
        // called until a node was removed
    });

    // listen for node list changes
    nodes.on( "change", function( nodeList ){
        // beside the `add` and `remove` events a single "change" event will be emitted
    });

    // listen for errors
    nodes.on( "error", function( err ){
        // E.g. called if a invalid filter was used or no lookup server is available
    });

});

Config

• lookupdHTTPAddresses : ( String|String[] required ) A single or multiple nsqlookupd hosts. This is also a configuration of 'nsqjs'
• lookupdPollInterval : ( Number optional: default = 60 ) Time in seconds to poll the nsqlookupd servers to sync the available nodes. This is also a configuration of 'nsqjs'
• active : ( Boolean optional: default = true ) Configuration to (de)activate the nsq nodes on startup

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?

.list( cb )

Get a list of the current nodes

• cb : ( Function optional ): Callback to get the list of nodes

Return

( Self ): The instance itself for chaining.

Example:

nodes.list( function( err, nodes ){
    if( err ){
        // handle the error
    }
    console.log( nodes ) // -> an array of nodes. E.g.: ( )`users`, `logins`, ... )
});

Events

add

A new node was added

Arguments

• node : ( String ) The new node

Example:

nodes.on( "add", function( node ){
    // called until a new node arrived
});

remove

A existing node was removed

Arguments

• node : ( String ) The removed node

Example:

nodes.on( "remove", function( node ){
    // called until a node was removed
});

change

The list of nodes changed

Arguments

• nodes : ( String[] ) A list of current nodes

Example:

nodes.on( "change", function( nodeList ){
    // beside the `add` and `remove` events a single "change" event will be emitted
});

error

An error occurred. E.g. called if a invalid filter was used or no lookup server is available

Arguments

• err : ( Error ) The error object.

Example:

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

ready

Emitted once the list of nodes where received the first time. 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:

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

Release History

Version	Date	Description
1.1.0	2019-01-25	now able to handle the formats of nsq < and > 1.x
1.0.0	2019-01-25	updated nodes response handler to match nsq >= 1.x format
0.0.3	2016-05-04	Another configuration bugfix
0.0.2	2016-05-04	Bugfix configuration and update to lodash
0.0.1	2015-11-27	Initial commit

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.