introduce build with scm changes only feature

httpApi/index.js

@@ -42,8 +42,9 @@ exports.register = function(app) {
 						logger.log('Run "' + projectName + '"');
 						distributor.run({
 							projectName: projectName,
+							withScmChangesOnly: body.withScmChangesOnly,
 							initiator: {type: 'httpApi'}
-						}, _.noop);
+						});
 					}
 
 				}

lib/distributor.js

@@ -216,6 +216,22 @@ Distributor.prototype.run = function(params, callback) {
 	Steppy(
 		function() {
 			project = _(self.projects).findWhere({name: params.projectName});
+
+			if (params.withScmChangesOnly) {
+				self.nodes[0].hasScmChanges(project, this.slot());
+			} else {
+				this.pass(null);
+			}
+		},
+		function(err, hasScmChanges) {
+			if (params.withScmChangesOnly && !hasScmChanges) {
+				logger.log(
+					'Building of "%s" skipped coz no scm changes',
+					project.name
+				);
+				return callback();
+			}
+
 			self._updateBuild({}, {
 				project: project,
 				initiator: params.initiator,

lib/executor/base.js

@@ -26,6 +26,11 @@ Executor.prototype._runStep = function(params, callback) {
 
 };
 
+// Does current project scm has new changes to build
+Executor.prototype.hasScmChanges = function(callback) {
+
+};
+
 Executor.prototype.run = function(params, callback) {
 	var self = this,
 		project = _({}).extend(self.project, params);

lib/executor/local.js

@@ -20,7 +20,7 @@ Executor.prototype._createScm = function(params) {
 	return createScm(params);
 };
 
-Executor.prototype._getSources = function(params, callback) {
+Executor.prototype._getChanges = function(params, callback) {
 	var self = this,
 		scm, isFirstRun, oldRev;
 	Steppy(
@@ -65,8 +65,34 @@ Executor.prototype._getSources = function(params, callback) {
 		},
 		function(err, changes) {
 			var target = self._getTarget(params.rev, changes);
-			this.pass(target.changes);
-			scm.update(target.rev, this.slot());
+			this.pass({
+				scm: scm,
+				oldRev: oldRev,
+				rev: target.rev,
+				changes: target.changes
+			});
+		},
+		callback
+	);
+};
+
+Executor.prototype.hasScmChanges = function(callback) {
+	this._getChanges(this.project.scm, function(err, data) {
+		callback(err, !err && data.changes.length > 0);
+	});
+};
+
+Executor.prototype._getSources = function(params, callback) {
+	var self = this,
+		scm;
+	Steppy(
+		function() {
+			self._getChanges(params, this.slot());
+		},
+		function(err, data) {
+			scm = data.scm;
+			this.pass(data.changes);
+			scm.update(data.rev, this.slot());
 		},
 		function(err, changes) {
 			scm.getCurrent(this.slot());

lib/node.js

@@ -83,6 +83,10 @@ Node.prototype._createExecutor = function(project) {
 	});
 };
 
+Node.prototype.hasScmChanges = function(project, callback) {
+	this._createExecutor(project).hasScmChanges(callback);
+};
+
 Node.prototype.run = function(project, params, callback) {
 	var self = this;
 

test/executor.js

@@ -46,10 +46,7 @@ var expect = require('expect.js'),
 			});
 
 			it('should run without errors', function(done) {
-				executor.run({}, function(err) {
-					expect(err).not.ok();
-					done();
-				});
+				executor.run({}, done);
 				executor.on('scmData', function(data) {
 					scmData = data;
 				});
@@ -67,6 +64,18 @@ var expect = require('expect.js'),
 			);
 		});
 
+		var itHasScmChanges = function(value) {
+			it((value ? 'should' : 'should`t') + ' has scm changes',
+				function(done) {
+					executor.hasScmChanges(function(err, hasScmChanges) {
+						if (err) return done(err);
+						expect(hasScmChanges).equal(value);
+						done();
+					});
+				}
+			);
+		};
+
 		_(['first revision', /^first revision$/]).each(function(comment) {
 
 			describe('with scm rev default and catch rev ' + comment, function() {
@@ -99,6 +108,8 @@ var expect = require('expect.js'),
 						});
 					});
 
+				itHasScmChanges(true);
+
 				it('should run it again without errors', function(done) {
 					executor.run({}, done);
 				});
@@ -113,6 +124,8 @@ var expect = require('expect.js'),
 						});
 					}
 				);
+
+				itHasScmChanges(false);
 			});
 
 		});
@@ -140,6 +153,8 @@ var expect = require('expect.js'),
 					});
 				});
 
+				itHasScmChanges(true);
+
 				it('scm data should be rev: 2, changes: [0, 2], not latest',
 					function() {
 						expect(scmData).eql({
@@ -164,6 +179,8 @@ var expect = require('expect.js'),
 					}
 				);
 
+				itHasScmChanges(false);
+
 			});
 
 		});