you can now set the variable in service.json, which can be used to st…

…art multiple copies of the service.

README.md

@@ -100,6 +100,7 @@ Here's an example:
   },
   "ndm-test2": {
     "description": "the awesome service",
+    "processes": 3,
     "module": "be-awesome",
     "scripts": {
       "start": "./bin/foo.js"
@@ -112,7 +113,7 @@ Here's an example:
     }
   },
   "env": {
-    "APP": "my-test-app",
+    "APP": "my-test-app-%i",
     "NODE_ENV": "production"
   },
   "args": {
@@ -126,6 +127,10 @@ Here's an example:
 * **scripts:** scripts that can be executed by ndm. When generating service wrappers the `start` script is used.
 * **env:** string environment variables available within the script executed by the ndm wrapper.
 * **args:** command-line-arguments available to the script executed by the ndm wrapper.
+* **processes:** how many copies of the service should be run.
+  * useful for taking advantage of multiple cpus, defaults to 1 process.
+* **`%i`:** `%i` is a place-holder for the process # if you're running multiple processes.
+  * this can be useful if you want each process to bind to a different port, e.g., `800%i`.
 
 Defaults for all services are in the top-level `env` and `args` fields. Each services can override and extend the defaults in its own options stanza.
 

lib/service.js

@@ -275,43 +275,53 @@ function parseServiceJson(serviceNameFilter, serviceJson) {
   Object.keys(serviceJson).forEach(function(serviceName) {
     if (serviceName === 'env' || serviceName === 'args') return;
 
-    var serviceConfig = serviceJson[serviceName];
-
-    // apply sane defaults as we create
-    // the services.
-    var service = new Service(_.extend(
-      {
-        module: serviceName,
-        name: serviceName
-      },
-      serviceConfig
-    ));
-
-    // override env and args with global args and env.
-    service.env = _.extend({},
-      dropInterviewQuestions(serviceJson.env),
-      dropInterviewQuestions(serviceConfig.env)
-    );
-
-    service.args = serviceConfig.args;
-
-    if (_.isArray(serviceConfig.args)) {
-      // combine arrays of arguments, if both top-level args.
-      // and service-level args are an array.
-      if (_.isArray(serviceJson.args)) service.args = [].concat(serviceJson.args, service.args);
-    } else {
-      // merge objects together if top-level, and service level
-      // arguments are maps.
-      service.args = _.extend({},
-        dropInterviewQuestions(serviceJson.args),
-        dropInterviewQuestions(serviceConfig.args)
+    var serviceConfig = serviceJson[serviceName],
+      processCount = serviceConfig.processes || 1;
+
+    // if services have a process count > 1,
+    // we'll create multiple run-scripts for them.
+    _.range(processCount).forEach(function(i) {
+
+      // apply sane defaults as we create
+      // the services.
+      var service = new Service(_.extend(
+        {
+          module: serviceName,
+          name: i > 0 ? (serviceName + '-' + i) : serviceName
+        },
+        serviceConfig
+      ));
+
+      // override env and args with global args and env.
+      service.env = _.extend({},
+        dropInterviewQuestions(serviceJson.env),
+        dropInterviewQuestions(serviceConfig.env)
       );
-    }
-
-    // we can optionall filter to a specific service name.
-    if (serviceNameFilter && service.name !== serviceNameFilter && !config.globalPackage) return;
 
-    services.push(service);
+      service.args = serviceConfig.args;
+
+      if (_.isArray(serviceConfig.args)) {
+        // combine arrays of arguments, if both top-level args.
+        // and service-level args are an array.
+        if (_.isArray(serviceJson.args)) service.args = [].concat(serviceJson.args, service.args);
+      } else {
+        // merge objects together if top-level, and service level
+        // arguments are maps.
+        service.args = _.extend({},
+          dropInterviewQuestions(serviceJson.args),
+          dropInterviewQuestions(serviceConfig.args)
+        );
+      }
+
+      // we can optionaly filter to a specific service name.
+      if (serviceNameFilter && service.name !== serviceNameFilter && !config.globalPackage) return;
+
+      // replace placeholder variables
+      // in the service.json.
+      expandVariables(service, i);
+
+      services.push(service);
+    });
   });
 
   return services;
@@ -326,6 +336,30 @@ function dropInterviewQuestions(o) {
   }, {});
 }
 
+// the %i placeholder can be used to reference the process
+// number in args/env variables within service.json.
+function expandVariables(service, processNumber) {
+  // first the simple case of env, which is always an object.
+  service.env = _.reduce(service.env, function(result, v, k) {
+    var value = typeof v === 'string' ? v.replace(/%i/g, processNumber) : v;
+    return (result[k] = value, result)
+  }, {});
+
+
+  // next, the more annoying usecase of args which can be
+  // an array on an object.
+  if (_.isArray(service.args)) {
+    service.args = _.map(service.args, function(arg) {
+      return typeof arg === 'string' ? arg.replace(/%i/g, processNumber) : arg;
+    });
+  } else {
+    service.args = _.reduce(service.args, function(result, v, k) {
+      var value = typeof v === 'string' ? v.replace(/%i/g, processNumber) : v;
+      return (result[k] = value, result)
+    }, {});
+  }
+};
+
 // look for a service manifest in cascade of logical places.
 exports._serviceJsonPath = function(serviceNameFilter) {
   var config = require('./config')(),

test/fixtures/multi-process-service.json

@@ -0,0 +1,16 @@
+{
+  "awesome": {
+    "processes": 3,
+    "env": {
+      "FOO": "bar",
+      "PORT": "500%i"
+    },
+    "args": ["--process", "%i"]
+  },
+  "dude": {
+    "processes": 1,
+    "args": {
+      "--port": "808%i"
+    }
+  }
+}

test/service-test.js

@@ -1,6 +1,7 @@
 require('../lib/config')({headless: true}); // turn off output in tests.
 
-var Lab = require('lab'),
+var _      = require('lodash'),
+  Lab      = require('lab'),
   lab      = exports.lab = Lab.script(),
   describe = lab.describe,
   it       = lab.it,
@@ -105,6 +106,48 @@ lab.experiment('service', function() {
     });
   });
 
+  lab.experiment('multiple processes', function() {
+    it('creates multiple services when processes value is set', function(done) {
+      Config({
+        serviceJsonPath: './test/fixtures/multi-process-service.json'
+      });
+      var services = Service.allServices(),
+        serviceNames = _.map(services, function(service) {
+          return service.name;
+        });
+
+      expect(services.length).to.eql(4);
+      expect(serviceNames).to.include('awesome');
+      expect(serviceNames).to.include('awesome-1');
+      expect(serviceNames).to.include('awesome-2');
+      expect(serviceNames).to.include('dude');
+      done();
+    });
+
+    it('replaces %i with process count in env and args', function(done) {
+      Config({
+        serviceJsonPath: './test/fixtures/multi-process-service.json'
+      });
+      var services = Service.allServices(),
+        service1 = services[0], // the multiple awesome services.
+        service2 = services[1];
+        service3 = services[3]; // the dude service.
+
+      // %i replaced in env object.
+      Lab.expect(service1.env.PORT).to.eql('5000');
+      Lab.expect(service2.env.PORT).to.eql('5001');
+
+      // %i replaced in args array.
+      Lab.expect(service1.args).to.include('0');
+      Lab.expect(service2.args).to.include('1');
+
+      // %i replaced in args object.
+      Lab.expect(service3.args['--port']).to.eql('8080');
+
+      return done();
+    });
+  });
+
   lab.experiment('commands', function() {
     it('should generate appropriate start/stop/restart commands for OSX', function(done) {
       Config({