#pomelo-admin

pomelo-admin is an admin console library for pomelo. It provides the a series of utilities to monitor the pomelo server clusters.

##Installation

npm install pomelo-admin

##Basic conception

###Process roles

There are three process roles in pomelo-admin: master, monitor and client.

• master - the master server process, collects and maintains all the client and monitor status and exports the cluster status for the clients.

• monitor - monitor proxy, in every server process which needs to be monitored. It should be started during the process starts and registers itself to the master server and reports the monitored process status to the master.

• client - pomelo-admin client process that fetches the status from master server, such as pomelo-admin-web and pomelo-cli.

###Message types

There are two message types of the communication between processes.

• request - bidirectional message that cooperated with response.

• notify - unidirectional message.

##Components

###ConsoleService

Main service of pomelo-admin that runs in both master and monitor processes. It maintains the master agent or monitor agent for the process, loads the registed modules and provides the messages routing service for the messages from other processes.

###MasterAgent

pomelo-admin agent that runs on the master process to provide the basic network communication and protocol encoding and decoding.

###MonitorAgent

pomelo-admin agent that runs on the monitor process to provide the basic network communication and protocol encoding and decoding.

###Module

Module is the place to implement the monitor logic, such as process status collecting. Developer can register modules in pomelo-admin to customize all kinds of system monitors.

There are three optional callback functions in each module.

• function masterHandler(agent, msg, cb) - callback in master process to process a message from monitor process or a timer event in master process.

• function monitorHandler(agent, msg, cb) - callback in monitor process to process a message from master process or a timer event in monitor process.

• function clientHandler(agent, msg, cb) - callback in master process to process a message from client.

The relations of the components is as below:

##Usage

var admin = require("pomelo-admin");

Create a consoleService instance in master process.

var masterConsole = admin.createMasterConsole({  
    port: masterPort  
});  

Register an admin module.

masterConsole.register(moduleId, module);  

Start masterConsole.

masterConsole.start(function(err) {  
  // start servers  
});  

Create a consoleService instance in monitor process.

var monitorConsole = admin.createMonitorConsole({  
    id: serverId,  
    type: serverType,  
    host: masterInfo.host,  
    port: masterInfo.port,  
    info: serverInfo  
}); 

##Customized modules

Developers can customize modules to collect and export additional status as they need.

###Simple example

var Module = function(app, opts) {
  opts = opts || {};
  this.type = opts.type || 'pull';  // pull or push 
  this.interval = opts.interval || 5; // pull or push interval
};

Module.moduleId = 'helloPomelo';

module.exports = Module;

Module.prototype.monitorHandler = function(agent, msg) {
  var word = agent.id + ' hello pomelo';
  // notify admin messages to master
  agent.notify(Module.moduleId, {serverId: agent.id, body: word});
};

Module.prototype.masterHandler = function(agent, msg) {
  // if no message, then notify all monitors to fetch datas
  if(!msg) {
    agent.notifyAll(Module.moduleId);
    return;
  }
  // collect data from monitor
  var data = agent.get(Module.moduleId);
  if(!data) {
    data = {};
    agent.set(Module.moduleId, data);
  }

  data[msg.serverId] = msg;
};

Module.prototype.clientHandler = function(agent, msg, cb) {
  // deal with client request,directly return data cached in master
  cb(null, agent.get(Module.moduleId) || {});
};

###Register customized modules

you must register your customized modules to pomelo to make it work.
write in app.js which is in your project's root directory

app.configure('production|development', function() {
  app.registerAdmin('helloPomelo',new helloPomelo());
});

##User level control
pomelo-admin defines user level for admin client to login master server in this schema

{
    "id": "user-1",
    "username": "admin",
    "password": "admin",
    "level": 1
}

level defines the user admin level
level 1 means the user has the admin permission, this user can do anything
other level user will have limited permission
currently add, stop, kill will require level 1 permission

note: by default you should provide adminUser.json file under the config dir
adminUser.json

[{
    "id": "user-1",
    "username": "admin",
    "password": "admin",
    "level": 1
}, {
    "id": "user-2",
    "username": "monitor",
    "password": "monitor",
    "level": 2
},{
    "id": "user-3",
    "username": "test",
    "password": "test",
    "level": 2
}
]

##Self-defined auth pomelo-admin provides a simple auth function in pomelo-admin auth
developers can provide self-defined auth in pomelo by
in master server

app.set('adminAuthUser', function(msg, cb){
  if(auth success) {
    cb(user);
  } else {
    cb(null);
  }
})

##Server master auth
server connect to master with authorization
pomelo-admin provides a simple auth function in pomelo-admin auth
developers can provide self-defined auth in pomelo by
in master server

app.set('adminAuthServerMaster', function(msg, cb){
  if(auth success) {
    cb('ok');
  } else {
    cb('bad');
  }
})

in monitor server

app.set('adminAuthServerMonitor', function(msg, cb){
  if(auth success) {
    cb('ok');
  } else {
    cb('bad');
  }
})

note: by default you should provide adminServer.json file under the config dir
adminServer.json

[{
    "type": "connector",
    "token": "agarxhqb98rpajloaxn34ga8xrunpagkjwlaw3ruxnpaagl29w4rxn"
}, {
    "type": "chat",
    "token": "agarxhqb98rpajloaxn34ga8xrunpagkjwlaw3ruxnpaagl29w4rxn"
},{
    "type": "gate",
    "token": "agarxhqb98rpajloaxn34ga8xrunpagkjwlaw3ruxnpaagl29w4rxn"
}
]

type is the serverType, token is a string you can genrate by yourself
when using in pomelo, you should fill all your servers with type:token

###Notes

pomelo-admin provides a series of useful system modules by default. But most of them are turned off by default. Add a simple line of code in app.js as below to enable them.

app.configure('development', function() {
  // enable the system monitor modules
  app.enable('systemMonitor');
});