Merge branch 'artifacts-from-ref-and-build-name-api' into 'master'

API for downloading latest successful build

## What does this MR do?

Implement parts of #4255, particularly the API.

## Are there points in the code the reviewer needs to double check?

I still made it that `ref` could be either branch, tag, or even SHA with:

``` ruby
# ref can't be HEAD, can only be branch/tag name or SHA
scope :latest_successful_for, ->(ref) do
  table = quoted_table_name
  # TODO: Use `where(ref: ref).or(sha: ref)` in Rails 5
  where("#{table}.ref = ? OR #{table}.sha = ?", ref, ref).
    success.order(id: :desc)
end
```

Because the reasons I put in:

* https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5142#note_13165543
* https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5142#note_13165921

But if you still think that it's not good to do it this way, I'll drop it and let's think about the other way to satisfy the requirement specified in https://gitlab.com/gitlab-org/gitlab-ce/issues/4255#note_13101233 It could be `status=any` or `sha=DEADBEAF`

## What are the relevant issue numbers?

Part of #4255

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5347

3 files changed, 196 insertions, 20 deletions

diff --git a/spec/models/build_spec.rb b/spec/models/build_spec.rb
index f9c9725a23d..7363ffcebeb 100644
--- a/spec/models/build_spec.rb
+++ b/spec/models/build_spec.rb
@@ -5,7 +5,9 @@ describe Ci::Build, models: true do
 
   let(:pipeline) do
     create(:ci_pipeline, project: project,
-                         sha: project.commit.id)
+                         sha: project.commit.id,
+                         ref: project.default_branch,
+                         status: 'success')
   end
 
   let(:build) { create(:ci_build, pipeline: pipeline) }
@@ -720,7 +722,7 @@ describe Ci::Build, models: true do
 
       describe '#erasable?' do
         subject { build.erasable? }
-        it { is_expected.to eq true }
+        it { is_expected.to be_truthy }
       end
 
       describe '#erased?' do
@@ -728,7 +730,7 @@ describe Ci::Build, models: true do
         subject { build.erased? }
 
         context 'build has not been erased' do
-          it { is_expected.to be false }
+          it { is_expected.to be_falsey }
         end
 
         context 'build has been erased' do
@@ -736,12 +738,13 @@ describe Ci::Build, models: true do
             build.erase
           end
 
-          it { is_expected.to be true }
+          it { is_expected.to be_truthy }
         end
       end
 
       context 'metadata and build trace are not available' do
         let!(:build) { create(:ci_build, :success, :artifacts) }
+
         before do
           build.remove_artifacts_metadata!
         end
@@ -763,19 +766,19 @@ describe Ci::Build, models: true do
 
   describe '#retryable?' do
     context 'when build is running' do
-      before { build.run! }
-
-      it 'should return false' do
-        expect(build.retryable?).to be false
+      before do
+        build.run!
       end
+
+      it { expect(build).not_to be_retryable }
     end
 
     context 'when build is finished' do
-      before { build.success! }
-
-      it 'should return true' do
-        expect(build.retryable?).to be true
+      before do
+        build.success!
       end
+
+      it { expect(build).to be_retryable }
     end
   end
 
diff --git a/spec/models/project_spec.rb b/spec/models/project_spec.rb
index e3e7319beb2..5629c75665a 100644
--- a/spec/models/project_spec.rb
+++ b/spec/models/project_spec.rb
@@ -377,7 +377,7 @@ describe Project, models: true do
   describe '#repository' do
     let(:project) { create(:project) }
 
-    it 'should return valid repo' do
+    it 'returns valid repo' do
       expect(project.repository).to be_kind_of(Repository)
     end
   end
@@ -1155,6 +1155,85 @@ describe Project, models: true do
     end
   end
 
+  describe '#latest_successful_builds_for' do
+    def create_pipeline(status = 'success')
+      create(:ci_pipeline, project: project,
+                           sha: project.commit.sha,
+                           ref: project.default_branch,
+                           status: status)
+    end
+
+    def create_build(new_pipeline = pipeline, name = 'test')
+      create(:ci_build, :success, :artifacts,
+             pipeline: new_pipeline,
+             status: new_pipeline.status,
+             name: name)
+    end
+
+    let(:project) { create(:project) }
+    let(:pipeline) { create_pipeline }
+
+    context 'with many builds' do
+      it 'gives the latest builds from latest pipeline' do
+        pipeline1 = create_pipeline
+        pipeline2 = create_pipeline
+        build1_p2 = create_build(pipeline2, 'test')
+        create_build(pipeline1, 'test')
+        create_build(pipeline1, 'test2')
+        build2_p2 = create_build(pipeline2, 'test2')
+
+        latest_builds = project.latest_successful_builds_for
+
+        expect(latest_builds).to contain_exactly(build2_p2, build1_p2)
+      end
+    end
+
+    context 'with succeeded pipeline' do
+      let!(:build) { create_build }
+
+      context 'standalone pipeline' do
+        it 'returns builds for ref for default_branch' do
+          builds = project.latest_successful_builds_for
+
+          expect(builds).to contain_exactly(build)
+        end
+
+        it 'returns empty relation if the build cannot be found' do
+          builds = project.latest_successful_builds_for('TAIL')
+
+          expect(builds).to be_kind_of(ActiveRecord::Relation)
+          expect(builds).to be_empty
+        end
+      end
+
+      context 'with some pending pipeline' do
+        before do
+          create_build(create_pipeline('pending'))
+        end
+
+        it 'gives the latest build from latest pipeline' do
+          latest_build = project.latest_successful_builds_for
+
+          expect(latest_build).to contain_exactly(build)
+        end
+      end
+    end
+
+    context 'with pending pipeline' do
+      before do
+        pipeline.update(status: 'pending')
+        create_build(pipeline)
+      end
+
+      it 'returns empty relation' do
+        builds = project.latest_successful_builds_for
+
+        expect(builds).to be_kind_of(ActiveRecord::Relation)
+        expect(builds).to be_empty
+      end
+    end
+  end
+
   describe '.where_paths_in' do
     context 'without any paths' do
       it 'returns an empty relation' do
diff --git a/spec/requests/api/builds_spec.rb b/spec/requests/api/builds_spec.rb
index f5b39c3d698..86a7b242fbe 100644
--- a/spec/requests/api/builds_spec.rb
+++ b/spec/requests/api/builds_spec.rb
@@ -1,15 +1,15 @@
 require 'spec_helper'
 
-describe API::API, api: true  do
+describe API::API, api: true do
   include ApiHelpers
 
   let(:user) { create(:user) }
   let(:api_user) { user }
-  let(:user2) { create(:user) }
   let!(:project) { create(:project, creator_id: user.id) }
   let!(:developer) { create(:project_member, :developer, user: user, project: project) }
-  let!(:reporter) { create(:project_member, :reporter, user: user2, project: project) }
-  let!(:pipeline) { create(:ci_pipeline, project: project, sha: project.commit.id) }
+  let(:reporter) { create(:project_member, :reporter, project: project) }
+  let(:guest) { create(:project_member, :guest, project: project) }
+  let!(:pipeline) { create(:ci_pipeline, project: project, sha: project.commit.id, ref: project.default_branch) }
   let!(:build) { create(:ci_build, pipeline: pipeline) }
 
   describe 'GET /projects/:id/builds ' do
@@ -172,10 +172,104 @@ describe API::API, api: true  do
     end
   end
 
+  describe 'GET /projects/:id/artifacts/:ref_name/download?job=name' do
+    let(:api_user) { reporter.user }
+    let(:build) { create(:ci_build, :success, :artifacts, pipeline: pipeline) }
+
+    def path_for_ref(ref = pipeline.ref, job = build.name)
+      api("/projects/#{project.id}/builds/artifacts/#{ref}/download?job=#{job}", api_user)
+    end
+
+    context 'when not logged in' do
+      let(:api_user) { nil }
+
+      before do
+        get path_for_ref
+      end
+
+      it 'gives 401' do
+        expect(response).to have_http_status(401)
+      end
+    end
+
+    context 'when logging as guest' do
+      let(:api_user) { guest.user }
+
+      before do
+        get path_for_ref
+      end
+
+      it 'gives 403' do
+        expect(response).to have_http_status(403)
+      end
+    end
+
+    context 'non-existing build' do
+      shared_examples 'not found' do
+        it { expect(response).to have_http_status(:not_found) }
+      end
+
+      context 'has no such ref' do
+        before do
+          get path_for_ref('TAIL', build.name)
+        end
+
+        it_behaves_like 'not found'
+      end
+
+      context 'has no such build' do
+        before do
+          get path_for_ref(pipeline.ref, 'NOBUILD')
+        end
+
+        it_behaves_like 'not found'
+      end
+    end
+
+    context 'find proper build' do
+      shared_examples 'a valid file' do
+        let(:download_headers) do
+          { 'Content-Transfer-Encoding' => 'binary',
+            'Content-Disposition' =>
+              "attachment; filename=#{build.artifacts_file.filename}" }
+        end
+
+        it { expect(response).to have_http_status(200) }
+        it { expect(response.headers).to include(download_headers) }
+      end
+
+      context 'with regular branch' do
+        before do
+          pipeline.update(ref: 'master',
+                          sha: project.commit('master').sha)
+
+          get path_for_ref('master')
+        end
+
+        it_behaves_like 'a valid file'
+      end
+
+      context 'with branch name containing slash' do
+        before do
+          pipeline.update(ref: 'improve/awesome',
+                          sha: project.commit('improve/awesome').sha)
+        end
+
+        before do
+          get path_for_ref('improve/awesome')
+        end
+
+        it_behaves_like 'a valid file'
+      end
+    end
+  end
+
   describe 'GET /projects/:id/builds/:build_id/trace' do
     let(:build) { create(:ci_build, :trace, pipeline: pipeline) }
 
-    before { get api("/projects/#{project.id}/builds/#{build.id}/trace", api_user) }
+    before do
+      get api("/projects/#{project.id}/builds/#{build.id}/trace", api_user)
+    end
 
     context 'authorized user' do
       it 'should return specific build trace' do
@@ -205,7 +299,7 @@ describe API::API, api: true  do
       end
 
       context 'user without :update_build permission' do
-        let(:api_user) { user2 }
+        let(:api_user) { reporter.user }
 
         it 'should not cancel build' do
           expect(response).to have_http_status(403)
@@ -237,7 +331,7 @@ describe API::API, api: true  do
       end
 
       context 'user without :update_build permission' do
-        let(:api_user) { user2 }
+        let(:api_user) { reporter.user }
 
         it 'should not retry build' do
           expect(response).to have_http_status(403)