Support go-source meta tag for godoc.org

changelogs/unreleased/31397-go-get-meta-source.yml

+---
+title: Support go-source meta tag for godoc.org
+merge_request: 19888
+author: Ethan Reesor (@firelizzard)
+type: changed

doc/user/project/index.md

@@ -200,9 +200,14 @@ When [renaming a user](../profile/index.md#changing-your-username),
 
 ## Use your project as a Go package
 
-Any project can be used as a Go package including private projects in subgroups. To use packages
-hosted in private projects with the `go get` command, use a [`.netrc` file](https://ec.haxx.se/usingcurl-netrc.html)
-and a [personal access token](../profile/personal_access_tokens.md) in the password field.
+Any project can be used as a Go package including private projects in subgroups.
+GitLab responds correctly to `go get` and `godoc.org` discovery requests,
+including the [`go-import`](https://golang.org/cmd/go/#hdr-Remote_import_paths)
+and [`go-source`](https://github.com/golang/gddo/wiki/Source-Code-Links) meta
+tags, respectively. To use packages hosted in private projects with the `go get`
+command, use a [`.netrc` file](https://ec.haxx.se/usingcurl-netrc.html) and a
+[personal access token](../profile/personal_access_tokens.md) in the password
+field.
 
 For example:
 

lib/gitlab/middleware/go.rb

@@ -25,13 +25,13 @@ module Gitlab
       def render_go_doc(request)
         return unless go_request?(request)
 
-        path = project_path(request)
+        path, branch = project_path(request)
         return unless path
 
-        body = go_body(path)
+        body, code = go_response(path, branch)
         return unless body
 
-        response = Rack::Response.new(body, 200, { 'Content-Type' => 'text/html' })
+        response = Rack::Response.new(body, code, { 'Content-Type' => 'text/html' })
         response.finish
       end
 
@@ -39,8 +39,15 @@ module Gitlab
         request["go-get"].to_i == 1 && request.env["PATH_INFO"].present?
       end
 
-      def go_body(path)
+      def go_response(path, branch)
         config = Gitlab.config
+        body_tag = content_tag :body, "go get #{config.gitlab.url}/#{path}"
+
+        unless branch
+          html_tag = content_tag :html, body_tag
+          return html_tag, 404
+        end
+
         project_url = Gitlab::Utils.append_path(config.gitlab.url, path)
         import_prefix = strip_url(project_url.to_s)
 
@@ -52,9 +59,11 @@ module Gitlab
                            "#{project_url}.git"
                          end
 
-        meta_tag = tag :meta, name: 'go-import', content: "#{import_prefix} git #{repository_url}"
-        head_tag = content_tag :head, meta_tag
-        content_tag :html, head_tag
+        meta_import_tag = tag :meta, name: 'go-import', content: "#{import_prefix} git #{repository_url}"
+        meta_source_tag = tag :meta, name: 'go-source', content: "#{import_prefix} #{project_url} #{project_url}/tree/#{branch}{/dir} #{project_url}/blob/#{branch}{/dir}/{file}#L{line}"
+        head_tag = content_tag :head, meta_import_tag + meta_source_tag
+        html_tag = content_tag :html, head_tag + body_tag
+        [html_tag, 200]
       end
 
       def strip_url(url)
@@ -80,9 +89,6 @@ module Gitlab
         path_segments = path.split('/')
         simple_project_path = path_segments.first(2).join('/')
 
-        # If the path is at most 2 segments long, it is a simple `namespace/project` path and we're done
-        return simple_project_path if path_segments.length <= 2
-
         project_paths = []
         begin
           project_paths << path_segments.join('/')
@@ -94,7 +100,7 @@ module Gitlab
 
         if project
           # If a project is found and the user has access, we return the full project path
-          project.full_path
+          return project.full_path, project.default_branch
         else
           # If not, we return the first two components as if it were a simple `namespace/project` path,
           # so that we don't reveal the existence of a nested project the user doesn't have access to.
@@ -105,7 +111,7 @@ module Gitlab
           # `go get gitlab.com/group/subgroup/project/subpackage` will not work for private projects.
           # `go get gitlab.com/group/subgroup/project.git/subpackage` will work, since Go is smart enough
           # to figure that out. `import 'gitlab.com/...'` behaves the same as `go get`.
-          simple_project_path
+          return simple_project_path, 'master'
         end
       end
 

spec/lib/gitlab/middleware/go_spec.rb

@@ -30,13 +30,13 @@ describe Gitlab::Middleware::Go do
 
       shared_examples 'go-get=1' do |enabled_protocol:|
         context 'with simple 2-segment project path' do
-          let!(:project) { create(:project, :private) }
+          let!(:project) { create(:project, :private, :repository) }
 
           context 'with subpackages' do
             let(:path) { "#{project.full_path}/subpackage" }
 
             it 'returns the full project path' do
-              expect_response_with_path(go, enabled_protocol, project.full_path)
+              expect_response_with_path(go, enabled_protocol, project.full_path, project.default_branch)
             end
           end
 
@@ -44,19 +44,19 @@ describe Gitlab::Middleware::Go do
             let(:path) { project.full_path }
 
             it 'returns the full project path' do
-              expect_response_with_path(go, enabled_protocol, project.full_path)
+              expect_response_with_path(go, enabled_protocol, project.full_path, project.default_branch)
             end
           end
         end
 
         context 'with a nested project path' do
           let(:group) { create(:group, :nested) }
-          let!(:project) { create(:project, :public, namespace: group) }
+          let!(:project) { create(:project, :public, :repository, namespace: group) }
 
           shared_examples 'a nested project' do
             context 'when the project is public' do
               it 'returns the full project path' do
-                expect_response_with_path(go, enabled_protocol, project.full_path)
+                expect_response_with_path(go, enabled_protocol, project.full_path, project.default_branch)
               end
             end
 
@@ -67,7 +67,7 @@ describe Gitlab::Middleware::Go do
 
               shared_examples 'unauthorized' do
                 it 'returns the 2-segment group path' do
-                  expect_response_with_path(go, enabled_protocol, group.full_path)
+                  expect_response_with_path(go, enabled_protocol, group.full_path, project.default_branch)
                 end
               end
 
@@ -85,7 +85,7 @@ describe Gitlab::Middleware::Go do
                 shared_examples 'authenticated' do
                   context 'with access to the project' do
                     it 'returns the full project path' do
-                      expect_response_with_path(go, enabled_protocol, project.full_path)
+                      expect_response_with_path(go, enabled_protocol, project.full_path, project.default_branch)
                     end
                   end
 
@@ -160,6 +160,36 @@ describe Gitlab::Middleware::Go do
             go
           end
         end
+
+        context 'with a public project without a repository' do
+          let!(:project) { create(:project, :public) }
+          let(:path) { project.full_path }
+
+          it 'returns 404' do
+            response = go
+            expect(response[0]).to eq(404)
+            expect(response[1]['Content-Type']).to eq('text/html')
+            expected_body = %{<html><body>go get #{Gitlab.config.gitlab.url}/#{project.full_path}</body></html>}
+            expect(response[2].body).to eq([expected_body])
+          end
+        end
+
+        context 'with a non-standard head' do
+          let(:user) { create(:user) }
+          let!(:project) { create(:project, :public, :repository) }
+          let(:path) { project.full_path }
+          let(:default_branch) { 'default_branch' }
+
+          before do
+            project.add_maintainer(user)
+            project.repository.add_branch(user, default_branch, 'master')
+            project.change_head(default_branch)
+          end
+
+          it 'returns the full project path' do
+            expect_response_with_path(go, enabled_protocol, project.full_path, default_branch)
+          end
+        end
       end
 
       context 'with SSH disabled' do
@@ -199,16 +229,17 @@ describe Gitlab::Middleware::Go do
       middleware.call(env)
     end
 
-    def expect_response_with_path(response, protocol, path)
+    def expect_response_with_path(response, protocol, path, branch)
       repository_url = case protocol
                        when :ssh
                          "ssh://#{Gitlab.config.gitlab.user}@#{Gitlab.config.gitlab.host}/#{path}.git"
                        when :http, nil
                          "http://#{Gitlab.config.gitlab.host}/#{path}.git"
                        end
+      project_url = "http://#{Gitlab.config.gitlab.host}/#{path}"
       expect(response[0]).to eq(200)
       expect(response[1]['Content-Type']).to eq('text/html')
-      expected_body = %{<html><head><meta name="go-import" content="#{Gitlab.config.gitlab.host}/#{path} git #{repository_url}" /></head></html>}
+      expected_body = %{<html><head><meta name="go-import" content="#{Gitlab.config.gitlab.host}/#{path} git #{repository_url}" /><meta name="go-source" content="#{Gitlab.config.gitlab.host}/#{path} #{project_url} #{project_url}/tree/#{branch}{/dir} #{project_url}/blob/#{branch}{/dir}/{file}#L{line}" /></head><body>go get #{Gitlab.config.gitlab.url}/#{path}</body></html>}
       expect(response[2].body).to eq([expected_body])
     end
   end