Netmorphic

Netmorphic is a library for testing networked applications, such as REST clients over HTTP, and database clients over TCP.

User can include Netmorphic in thier own server or for quick start clone and configure canned Netmorphic server.

By configuring Netmorphic based server as "man in the middle" (or as Proxy for HTTP requests) between the client and server components (over HTTP or TCP), simple connections get transformed into "programmable connections". Users can program these "programmable connection" to induce different network behaviours.

table of contents

• Installation
• HTTP Configuration
• TCP Configuration
• Quick Start
• Handlers
• Multitenancy
• HTTP Config Api
• Config Editor UI

---

installation

npm install netmorphic

Include in JavaScript file

var nm = require('netmorphic')

---

Configurations

Configure your proxy with a json object. See the examples below.

HTTP Configuration

RESTful routing is made available through the use of the Router module.

{
"/path/to/endpoint":{ // this is static url for the endpoint
"host":"endpoint.host.example.com", // the host of the endpoint server
"port":80, // the port of the endpoint
"type":"slow", // the handler type to use. See section on handlers below
"method":"get", // request method
"latency": 100 // latency parameter to use with "slow" handler type
},
"/product/{id}":{ // this is a dynamic url. The value of id will be found at req.params.id
"host":"endpoint.host.example.com",
"port":80,
"type":"flakey", // another type of handler
"method":"get",
"hi" : 2000,
"lo" : 500,
},
"addresses" : [] // leave this empty if you don't need to bother with multi-tenancy
}

TCP configuration

TCP configuration is similar to the above, with two major exceptions. The first is that multi-tenancy is not currently supported, so there is no 'global' key at the top level. The second is that urls are replaced with the the port number that the proxy server will listen on.

{
"10001": { // the port the proxy will listen on
"host" : "127.0.0.1", // and proxy incoming streams to this host
"port" : 3124, // and this port
"type" : "normal" // using this TCP handler
},
"10002": { // use this port for a slow proxy
"host" : "127.0.0.1",
"port" : 3124,
"type" : "slow",
"latency" : 5000
},
"10003": { // use this port for a drop proxy
"host" : "127.0.0.1",
"port" : 3124,
"type" : "drop",
"lo" : 1000,
"high" : 5000
},
"10004": { // use this port for a bumpy proxy
"host" : "127.0.0.1",
"port" : 3124,
"type" : "bumpy",
"lo" : 3500,
"high" : 7000
}
}

---

quick start

HTTP

config.json

{
"/path/to/endpoint":{
"host":"endpoint.host.example.com",
"port":80,
"type":"slow",
"method":"get",
"latency": 100
},
"/product/{id}":{
"host":"endpoint.host.example.com",
"port":80,
"type":"flakey",
"method":"get",
"hi" : 2000,
"lo" : 500
},
"addresses" : []
}

httpTest.js

var netmorphic = require('netmorphic').proxy
, CONFIG = require('./config.json')
, USE_CLUSTER = false
, CUSTOM_HANDLERS = false;
var apps = netmorphic(CONFIG, CUSTOM_HANDLERS, USE_CLUSTER); apps[0].app.listen(8000)

Verify http://server:8000/getconfig and use json editor available at http://server:8000/config/index.html to modify the configuration.

HTTP with Cluster2

httpTestCluster.js

var netmorphic = require('netmorphic').proxy
, monitor = require('netmorphic').monitor(3100) //3100 required for config sync-ing
, Cluster = require('cluster2')
, HTTPPORT = 8000
, CONFIG = require('./config.json')
, USE_CLUSTER = true
, CUSTOM_HANDLERS = false;
var apps = netmorphic(CONFIG, CUSTOM_HANDLERS, USE_CLUSTER, HTTPPORT);
var cluster = new Cluster({
monitor: monitor
})
cluster.listen(function(cb){
cb(apps)
});

Verify http://server:8000/getconfig and use the json editor available at http://server:8000/config/index.html to modify the configuration.

TCP

config.json

{
"/path/to/endpoint":{
"host":"endpoint.host.example.com",
"port":80,
"type":"slow",
"method":"get",
"latency": 100
},
"10001": {
"host" : "127.0.0.1",
"port" : 3124,
"type" : "normal"
},
"10002": {
"host" : "127.0.0.1",
"port" : 3124,
"type" : "slow",
"latency" : 5000
},
"10003": {
"host" : "127.0.0.1",
"port" : 3124,
"type" : "drop",
"lo" : 1000,
"high" : 5000
},
"10004": {
"host" : "127.0.0.1",
"port" : 3124,
"type" : "bumpy",
"lo" : 3500,
"high" : 7000
}
}

tcpTest.js

var netmorphic = require('netmorphic').proxy
, CONFIG = require('./config.json')
, HTTPPORT = 8000
, USE_CLUSTER = false
, CUSTOM_HANDLERS = false;
var apps = netmorphic(CONFIG, CUSTOM_HANDLERS, USE_CLUSTER, HTTPPORT);
//iterate over the TCP servers and start each one
apps.forEach(function(app){
app.app.listen(app.port)
})

TCP with Cluster2

tcpTestcluster.js

var netmorphic = require('netmorphic').proxy
, monitor = require('netmorphic').monitor(3100) // 3100 to run the monitor app
, Cluster = require('cluster2')
, HTTPPORT = 8000
, CONFIG = require('./config.json')
, USE_CLUSTER = true
, CUSTOM_HANDLERS = false;
var apps = netmorphic(CONFIG, CUSTOM_HANDLERS, USE_CLUSTER, HTTPPORT);
var cluster = new Cluster({
monitor: monitor
})
cluster.listen(function(cb){
cb(apps)
})

---

handlers

Handlers are the "morph" in netmorphic. They act upon your requests and streams. Parameters for your handlers are set in the config files. Netmorphic ships with a few handlers out of the box, namely:

• normal - plain proxy
• slow - buffers the outgoing request by a minimum latency
• flakey - buffers the request for a random latency between hi and lo values
• drop - drops request immediately or
• unresponsive - does not respond to the request

Additionally, custom handlers can be written to do anything. Pass an object of handler functions to the netmorphic constructor, like so:

var netmorphic = require('netmorphic').proxy
, CONFIG = require('./config.json')
, HTTPPORT = 8000
, CUSTOM_HANDLERS = require('files/my.custom.handlers.js') , USE_CLUSTER = false
, CUSTOM_HANDLERS = false;
var apps = netmorphic(CONFIG, CUSTOM_HANDLERS, USE_CLUSTER, HTTPPORT);

a custom HTTP handler file would look like this:

my.custom.handlers.js

// HTTP Custom Handler
// hint: it's just a function that handles the request and response streams...
module.exports['just proxy'] = function(req, res){
var config = req.serConfig; // the service config for this particular client
var proxy = req.proxy; // a proxy to use, if you need a proxy
proxy.proxyRequest(req, res, {
host:config.host,
port:config.port
});
}
// TCP Custom Handler
var ps = require('pause-stream'); // a stream that pauses
module.exports['vanilla tcp proxy'] = function(socket, service){
// socket is the client stream
// service is a TCP socket to use to proxy to the endpoint
var buffer = ps(); // create a pause stream
socket.pipe(buffer.pause()); // pipe the request to the buffer and pause it
service.connect(socket._CONFIG.port, socket._CONFIG.host, function(){
buffer.pipe(service); // pipe the buffered request to the endpoint
buffer.resume() // resume the buffer stream
});
service.pipe(socket); // pipe the endpoint connection back to the client connection
}

#Multitenancy For HTTP requests user can setup client specific config by defining Tenants. Clients are identified by looking at 'X-Forwarded-For' header.

{
global: { // 'global' is always client agnostic
'/path': {
host: '127.0.0.1',
port: 3200,
method: 'ALL',
type: 'testcase',
code: 1
}
},
test: { // 'test' is a user defined tenant
'/{key}': {
host: '127.0.0.1',
port: 3200,
method: 'ALL',
type: 'testcase',
code: 2
},
addresses: ['12.34.56.78'] // IP address for clients belonging to 'test' tenant
}
};

#HTTP Config Api Once netmorphic is started (Ref Quick Start) config can be got or set using the following HTTP Apis.

##Get Config User can get the whole configuration or for a given endpoint by specifying the tenant and url for HTTP or port for TCP.

http://<server>:<port>/getconfig
http://<server>:<port>/getconfig?srcUrl=<url or port>&tenant=<tenant>

Example: http://server:3000/getconfig?srcUrl=/path&tenant=global

##Set Config User can set configuration for only a given endpoint.

http://<server>:<port>/setconfig?srcUrl=<url or port>&tenant=<tenant>[&<p1>:<v1>&<p2>:<v2>&...]

example: http://server:3000/setconfig?srcUrl=/path&tenant=global&type=slow&latency=2000

#Config Editor UI Once netmorphic is started (Ref Quick Start) config can be edited through a simple JSON editor (credits: http://jsoneditoronline.org/) at the following link.

http://server:3000/config/index.html