Migrate Gitlab::Git::Wiki#page to Gitaly

Closes gitaly#677

lib/gitlab/git/wiki.rb

@@ -58,14 +58,13 @@ module Gitlab
       end
 
       def page(title:, version: nil, dir: nil)
-        if version
+        @repository.gitaly_migrate(:wiki_find_page) do |is_enabled|
-          version = Gitlab::Git::Commit.find(@repository, version).id
+          if is_enabled
+            gitaly_find_page(title: title, version: version, dir: dir)
+          else
+            gollum_find_page(title: title, version: version, dir: dir)
+          end
         end
-
-        gollum_page = gollum_wiki.page(title, version, dir)
-        return unless gollum_page
-
-        new_page(gollum_page)
       end
 
       def file(name, version)
@@ -146,6 +145,17 @@ module Gitlab
         nil
       end
 
+      def gollum_find_page(title:, version: nil, dir: nil)
+        if version
+          version = Gitlab::Git::Commit.find(@repository, version).id
+        end
+
+        gollum_page = gollum_wiki.page(title, version, dir)
+        return unless gollum_page
+
+        new_page(gollum_page)
+      end
+
       def gitaly_write_page(name, format, content, commit_details)
         gitaly_wiki_client.write_page(name, format, content, commit_details)
       end
@@ -153,6 +163,13 @@ module Gitlab
       def gitaly_delete_page(page_path, commit_details)
         gitaly_wiki_client.delete_page(page_path, commit_details)
       end
+
+      def gitaly_find_page(title:, version: nil, dir: nil)
+        wiki_page, version = gitaly_wiki_client.find_page(title: title, version: version, dir: dir)
+        return unless wiki_page
+
+        Gitlab::Git::WikiPage.new(wiki_page, version)
+      end
     end
   end
 end

lib/gitlab/gitaly_client/wiki_page.rb

@@ -0,0 +1,25 @@
+module Gitlab
+  module GitalyClient
+    class WikiPage
+      FIELDS = %i(title format url_path path name historical raw_data).freeze
+
+      attr_accessor(*FIELDS)
+
+      def initialize(params)
+        params = params.with_indifferent_access
+
+        FIELDS.each do |field|
+          instance_variable_set("@#{field}", params[field])
+        end
+      end
+
+      def historical?
+        @historical
+      end
+
+      def format
+        @format.to_sym
+      end
+    end
+  end
+end

lib/gitlab/gitaly_client/wiki_service.rb

@@ -47,6 +47,39 @@ module Gitlab
         GitalyClient.call(@repository.storage, :wiki_service, :wiki_delete_page, request)
       end
 
+      def find_page(title:, version: nil, dir: nil)
+        request = Gitaly::WikiFindPageRequest.new(
+          repository: @gitaly_repo,
+          title: GitalyClient.encode(title),
+          revision: GitalyClient.encode(version),
+          directory: GitalyClient.encode(dir)
+        )
+
+        response = GitalyClient.call(@repository.storage, :wiki_service, :wiki_find_page, request)
+        wiki_page = version = nil
+
+        response.each do |message|
+          page = message.page
+          next unless page
+
+          if wiki_page
+            wiki_page.raw_data << page.raw_data
+          else
+            wiki_page = GitalyClient::WikiPage.new(page.to_h)
+            # All gRPC strings in a response are frozen, so we get
+            # an unfrozen version here so appending in the else clause below doesn't blow up.
+            wiki_page.raw_data = wiki_page.raw_data.dup
+
+            version = Gitlab::Git::WikiPageVersion.new(
+              Gitlab::Git::Commit.decorate(@repository, page.version.commit),
+              page.version.format
+            )
+          end
+        end
+
+        [wiki_page, version]
+      end
+
       private
 
       def gitaly_commit_details(commit_details)

spec/models/project_wiki_spec.rb

@@ -117,6 +117,7 @@ describe ProjectWiki do
   end
 
   describe "#find_page" do
+    shared_examples 'finding a wiki page' do
       before do
         create_page("index page", "This is an awesome Gollum Wiki")
       end
@@ -145,6 +146,15 @@ describe ProjectWiki do
       end
     end
 
+    context 'when Gitaly wiki_find_page is enabled' do
+      it_behaves_like 'finding a wiki page'
+    end
+
+    context 'when Gitaly wiki_find_page is disabled', :skip_gitaly_mock do
+      it_behaves_like 'finding a wiki page'
+    end
+  end
+
   describe '#find_file' do
     before do
       file = Gollum::File.new(subject.wiki)