Add api endpoint for creating a pipeline

Add a new endpoint in the new API for creating a new pipeline, and return the details of that pipeline.

changelogs/unreleased/create-pipeline-endpoint.yml

+---
+title: Add api endpoint for creating a pipeline
+merge_request: 7209
+author: Ido Leibovich

doc/api/pipelines.md

@@ -114,6 +114,51 @@ Example of response
 }
 ```
 
+## Create a new pipeline
+
+> [Introduced][ce-7209] in GitLab 8.14
+
+```
+POST /projects/:id/pipeline
+```
+
+| Attribute  | Type    | Required | Description         |
+|------------|---------|----------|---------------------|
+| `id`       | integer | yes      | The ID of a project |
+| `ref`       | string | yes      | Reference to commit |
+
+```
+curl --request POST --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/projects/1/pipeline?ref=master"
+```
+
+Example of response
+
+```json
+{
+  "id": 61,
+  "sha": "384c444e840a515b23f21915ee5766b87068a70d",
+  "ref": "master",
+  "status": "pending",
+  "before_sha": "0000000000000000000000000000000000000000",
+  "tag": false,
+  "yaml_errors": null,
+  "user": {
+    "name": "Administrator",
+    "username": "root",
+    "id": 1,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/e64c7d89f26bd1972efa854d13d7dd61?s=80&d=identicon",
+    "web_url": "http://localhost:3000/root"
+  },
+  "created_at": "2016-11-04T09:36:13.747Z",
+  "updated_at": "2016-11-04T09:36:13.977Z",
+  "started_at": null,
+  "finished_at": null,
+  "committed_at": null,
+  "duration": null
+}
+```
+
 ## Retry failed builds in a pipeline
 
 > [Introduced][ce-5837] in GitLab 8.11
@@ -205,3 +250,4 @@ Response:
 ```
 
 [ce-5837]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5837
+[ce-7209]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7209

lib/api/pipelines.rb

@@ -22,6 +22,27 @@ module API
         pipelines = PipelinesFinder.new(user_project).execute(scope: params[:scope])
         present paginate(pipelines), with: Entities::Pipeline
       end
+      
+      desc 'Create a new pipeline' do
+        detail 'This feature was introduced in GitLab 8.14'
+        success Entities::Pipeline
+      end
+      params do
+        requires :ref, type: String,  desc: 'Reference'
+      end
+      post ':id/pipeline' do
+        authorize! :create_pipeline, user_project
+
+        new_pipeline = Ci::CreatePipelineService.new(user_project,
+                                                     current_user,
+                                                     declared_params(include_missing: false))
+                           .execute(ignore_skip_ci: true, save_on_errors: false)
+        if new_pipeline.persisted?
+          present new_pipeline, with: Entities::Pipeline
+        else
+          render_validation_error!(new_pipeline)
+        end
+      end
 
       desc 'Gets a specific pipeline for the project' do
         detail 'This feature was introduced in GitLab 8.11'

spec/requests/api/pipelines_spec.rb

@@ -41,6 +41,52 @@ describe API::API, api: true do
     end
   end
 
+  describe 'POST /projects/:id/pipeline ' do
+    context 'authorized user' do
+      context 'with gitlab-ci.yml' do
+        before { stub_ci_pipeline_to_return_yaml_file }
+
+        it 'creates and returns a new pipeline' do
+          expect do
+            post api("/projects/#{project.id}/pipeline", user), ref: project.default_branch
+          end.to change { Ci::Pipeline.count }.by(1)
+
+          expect(response).to have_http_status(201)
+          expect(json_response).to be_a Hash
+          expect(json_response['sha']).to eq project.commit.id
+        end
+
+        it 'fails when using an invalid ref' do
+          post api("/projects/#{project.id}/pipeline", user), ref: 'invalid_ref'
+
+          expect(response).to have_http_status(400)
+          expect(json_response['message']['base'].first).to eq 'Reference not found'
+          expect(json_response).not_to be_an Array
+        end
+      end
+
+      context 'without gitlab-ci.yml' do
+        it 'fails to create pipeline' do
+          post api("/projects/#{project.id}/pipeline", user), ref: project.default_branch
+
+          expect(response).to have_http_status(400)
+          expect(json_response['message']['base'].first).to eq 'Missing .gitlab-ci.yml file'
+          expect(json_response).not_to be_an Array
+        end
+      end
+    end
+
+    context 'unauthorized user' do
+      it 'does not create pipeline' do
+        post api("/projects/#{project.id}/pipeline", non_member), ref: project.default_branch
+
+        expect(response).to have_http_status(404)
+        expect(json_response['message']).to eq '404 Project Not Found'
+        expect(json_response).not_to be_an Array
+      end
+    end
+  end
+
   describe 'GET /projects/:id/pipelines/:pipeline_id' do
     context 'authorized user' do
       it 'returns project pipelines' do