Cocaine NodeJS Framework

Examples of usage

Create NodeJS app for Cocaine cloud

Let's start with simple NodeJS http application.

var http = require('http')

var server = new http.Server(function(req, res){
    var body = []
    req.on('data', function(data){
        body.push(data)
    })
    req.on('end', function(){
        res.writeHead(200, {
          'x-any-header': 'x-any-value',
          'content-type': 'text/plain'
        })
        res.end('hello, Cocaine!')
    })
})

server.listen(8080)

To get our app working in Cocaine cloud, let's add just a couple of things.

#!/path/to/node
var cocaine = require('cocaine')
var http = cocaine.http // monkey-patches node's original http server

var argv = require('optimist').argv //which is actually a hash
// looking like { opt: 'value'}

var worker = new cocaine.Worker(argv)

var handle = worker.getListenHandle("http") // the handle implements a
// low-level nodejs' listening tcp socket, and it makes nodejs
// understand cocaine streams.

var server = new http.Server(...) // the same thing as above

server.listen(handle) // as per [1], start listening on cocaine handle

To let the cocaine-runtime know what to run in our app, we put manifest.json:

{ "slave":"app.js" }

Since the app.js has to be an executable, we put shebang on first line and don't forget about setting an executable bit.

See the complete app here [2].

Deploy app to the cloud

git clone url/the_app
cd the_app
npm install
tar -czf ../the_app.tgz
cocaine-tool app upload -n the_app --package ../the_app.tgz --manifest manifest.json
>app the_app has been successfully uploaded

then,

cocaine-tool app start -n the_app -r default
>app the_app started
curl -v http://<cloud.front>/the_app/http/
>...

Make use of Cocaine services

var cocaine = require("cocaine")

var cli = new cocaine.Client(["localhost", 10053])

var log = new cli.Logger("myprefix") // logs lines like "myprefix/..."

cli.on('error', function(err){
    console.log('client error', err)
})

log.on('error', function(err){
    console.log('logger error', err)
})


log.connect()

log.on("connect", function() {

    cli.getServices(['geobase'], function(err, geo, ua){
        var names
        
        log.info("looking up regionId for ip 1.2.3.4")
        
        geo.region_id("1.2.3.4", function(err, regionId) {
            if(err) return _handleError(err)

            log.debug("found region %d for %s", regionId, "1.2.3.4")

            geo.names(regionId, function(err, names){
                if(err) return _handleError(err)

                log.debug("names for region %d are %s", regionId, names.join())

                geo.coordinates(regionId, function(coords){
                    if(err) return _handleError(err)

                    log.debug('coordinates for region %d are %s', regionId, coords.join())

                })
            })
        })
    })
})

function _handleError(err){
    console.log('service error', err)
}

See client-simple for complete source of the simplest cocaine client app.

Use Cocaine services from the outside of the cloud

To fully control a client to services, you can use Client. It resolves services for you, keeps services cache, and resets resolved services cache on locator disconnect.

var cli = new require('cocaine').Client()

var storage = cli.Service('storage')

storage.on('error', function(err){
    // reconnect on network error
})

storage.connect()

storage.on('connect', function(){
    storage0.write('collection','key','value', function(err){
        if(err){
            console.log('error writing to storage', err)
            return
        }
        
        console.log(done 'writing to storage')
    })
})

See client-reconnect for example of handling various socket-level failures when connecting and communicating to locator and target services.

Access your application as a Cocaine service

var cli = new require('cocaine').Client()
var app = cli.Service('the_app')

app.connect()

app.on('connect', function(){
    app.enqueue('handle','anydata', function(err, result){
        if(err) {
           console.log('app error', err)
        } else {
          console.log('app response is', result)
        }
    })
})

References

[1] http://nodejs.org/api/net.html#net_server_listen_handle_callback