loke-ipc

LOKE IPC (Inter-process comms) Library

UPDATE: breaking change! constructor parameters are now different. Accepts an options argument. Can also be provided with a NewRelic client agent so that requests can be tracked and analyzed by NewRelic.

Connecting

var lokeIpc = require('loke-ipc');
 
lokeIpc.connect()
.then(function(connection) {
   console.log('Connected!');
});

Alternatively use the constructor:

var Communications = require('loke-ipc').Communications;
 
var communications = new Communications(config);
communications.start()
.then(function() {
   console.log('Connected!');
});

Specify the location of RabbitMQ:

var lokeIpc = require('loke-ipc');
 
lokeIpc.connect({amqpUri:'amqp://localhost'})
.then(function(connection) {
   console.log('Connected!');
});

Using NewRelic:

var lokeIpc = require('loke-ipc');
var newRelic = require('new-relic');
 
// if a new relic client is provided it will be used
lokeIpc.connect({newRelic: newRelic})
.then(function(connection) {
   console.log('Connected!');
});

Using a custom logger:

var lokeIpc = require('loke-ipc');
var logger = require('./my/custom/logger');
 
// a custom logger must implement .info .debug .warn .error
lokeIpc.connect({logger: logger})
.then(function(connection) {
   logger.info('Connected!');
});

Consuming Services

var lokeIpc = require('loke-ipc');
 
lokeIpc.connect()
.then(function(connection) {
   return connection.getRpcClient();
})
.then(function(client) {
    client.request(/* ... */);
    // ...
});

Or use installed service manifests (see ipc-install):

$ ipc-install some-service@1

then

var lokeIpc = require('loke-ipc');
 
lokeIpc.connect()
.then(function(connection) {
  return connection.getRpcClient();
})
.then(function(client) {
  var someService = client.load('some-service');
  someService.doSomething(/*...*/);
});

Publishing Services

TODO: see the following methods:

exposeService exposeServices closeServices

RPC Events

When exposing RPC methods a number of events are fired from RPC service and proxied through to communications to assist with logging and debugging.

// events for any/all exposed services are emitted on the connection
connection.on('request:start', doStuff);
connection.on('request:complete', doStuff);
connection.on('request:error', doStuff);
 
// events for a specific exposed service are emitted on the RPC service itself
rpcSvc.on('request:start', doStuff);
rpcSvc.on('request:complete', doStuff);
rpcSvc.on('request:error', doStuff);

For the following events a request object is of type:

{
  id: 1,  // message ID
  method: 'myMethodName', // method name
  params: [] // array[*] of params passed to the method
}

The response object is of type:

{
  result: myResult, // response from the method (type: any)
  error: null,      // JSON-RPC error will be null if there is a result
  id: id            // the message ID from the request
}

In the event of an error:

{
  result: null,   // null result in case of error
  error: {
    code: -32000, // JSON-RPC error code
    message: "Failed abysmally",  // error description
    data: {}      // additional details (inner error or exception)
  },
  id: id
}

request:start

conn.on('request:start', function(e) {
  console.log(e.method); // the method name eg "getCustomers" (string)
  console.log(e.request); // the full request object
});

request:complete

conn.on('request:start', function(e) {
  console.log(e.method); // the method name eg "getCustomers" (string)
  console.log(e.request); // the full request object
  console.log(e.response); // the full response object
  console.log(e.duration); // the duration of the request in milliseconds (double)
});

request:error

conn.on('request:error', function(e) {
  // NOTE: method and request could be undefined depending on where error was thrown (ie: if before message was parsed)
  console.log(e.method); // the method name eg "getCustomers" (string)
  console.log(e.request); // the full request object
  console.log(e.error); // the error thrown (Error)
});

More

A custom logger can be provided. If none is provided then console will be used.

var lokeIpc = require('loke-ipc');
 
lokeIpc.connect(null, myCustomerLogger)
.then(function(connection) {
   console.log('Connected!');
});

CLI

The cli tools are configured using rc. This means config variables can be set in

• ~/.ipcrc
• ./.ipcrc (current directory, probably you project directory)

or by using a command line flag

--ipc_amqpuri='amqp://somehost'

The currently available variables are:

• amqpuri the amqp server to connect to

ipc-install

Usage: ipc-install <service>...

<service>    in the format serviceName@version

example

$ ipc-install orders@1
writing... /my/project/ipc_manifests/orders.json

ipc-repl

Usage: ipc-repl

example

$ ipc-repl
ipc> orders.ping()
'pong'
ipc>