Refactor cache refreshing/expiring

This refactors repository caching so it's possible to selectively
refresh certain caches, instead of just expiring and refreshing
everything.

To allow this the various methods that were cached (e.g. "tag_count" and
"readme") use a similar pattern that makes expiring and refreshing
their data much easier.

In this new setup caches are refreshed as follows:

1. After a commit (but before running ProjectCacheWorker) we expire some
   basic caches such as the commit count and repository size.

2. ProjectCacheWorker will recalculate the commit count, repository
   size, then refresh a specific set of caches based on the list of
   files changed in a push payload.

This requires a bunch of changes to the various methods that may be
cached. For one, data should not be cached if a branch used or the
entire repository does not exist. To prevent all these methods from
handling this manually this is taken care of in
Repository#cache_method_output. Some methods still manually check for
the existence of a repository but this result is also cached.

With selective flushing implemented ProjectCacheWorker no longer uses an
exclusive lease for all of its work. Instead this worker only uses a
lease to limit the number of times the repository size is updated as
this is a fairly expensive operation.

6 files changed, 352 insertions, 334 deletions

diff --git a/spec/models/project_spec.rb b/spec/models/project_spec.rb
index 25458e20618..e183fa88873 100644
--- a/spec/models/project_spec.rb
+++ b/spec/models/project_spec.rb
@@ -1572,7 +1572,7 @@ describe Project, models: true do
     end
 
     it 'expires the avatar cache' do
-      expect(project.repository).to receive(:expire_avatar_cache).with(project.default_branch)
+      expect(project.repository).to receive(:expire_avatar_cache)
       project.change_head(project.default_branch)
     end
 
diff --git a/spec/models/repository_spec.rb b/spec/models/repository_spec.rb
index 635130cf797..04afb8ebc98 100644
--- a/spec/models/repository_spec.rb
+++ b/spec/models/repository_spec.rb
@@ -464,11 +464,7 @@ describe Repository, models: true do
     end
   end
 
-  describe "#changelog" do
-    before do
-      repository.send(:cache).expire(:changelog)
-    end
-
+  describe "#changelog", caching: true do
     it 'accepts changelog' do
       expect(repository.tree).to receive(:blobs).and_return([TestBlob.new('changelog')])
 
@@ -500,17 +496,16 @@ describe Repository, models: true do
     end
   end
 
-  describe "#license_blob" do
+  describe "#license_blob", caching: true do
     before do
-      repository.send(:cache).expire(:license_blob)
       repository.remove_file(user, 'LICENSE', 'Remove LICENSE', 'master')
     end
 
     it 'handles when HEAD points to non-existent ref' do
       repository.commit_file(user, 'LICENSE', 'Copyright!', 'Add LICENSE', 'master', false)
-      rugged = double('rugged')
-      expect(rugged).to receive(:head_unborn?).and_return(true)
-      expect(repository).to receive(:rugged).and_return(rugged)
+
+      allow(repository).to receive(:file_on_head).
+        and_raise(Rugged::ReferenceError)
 
       expect(repository.license_blob).to be_nil
     end
@@ -537,22 +532,18 @@ describe Repository, models: true do
     end
   end
 
-  describe '#license_key' do
+  describe '#license_key', caching: true do
     before do
-      repository.send(:cache).expire(:license_key)
       repository.remove_file(user, 'LICENSE', 'Remove LICENSE', 'master')
     end
 
-    it 'handles when HEAD points to non-existent ref' do
-      repository.commit_file(user, 'LICENSE', 'Copyright!', 'Add LICENSE', 'master', false)
-      rugged = double('rugged')
-      expect(rugged).to receive(:head_unborn?).and_return(true)
-      expect(repository).to receive(:rugged).and_return(rugged)
-
+    it 'returns nil when no license is detected' do
       expect(repository.license_key).to be_nil
     end
 
-    it 'returns nil when no license is detected' do
+    it 'returns nil when the repository does not exist' do
+      expect(repository).to receive(:exists?).and_return(false)
+
       expect(repository.license_key).to be_nil
     end
 
@@ -569,7 +560,7 @@ describe Repository, models: true do
     end
   end
 
-  describe "#gitlab_ci_yml" do
+  describe "#gitlab_ci_yml", caching: true do
     it 'returns valid file' do
       files = [TestBlob.new('file'), TestBlob.new('.gitlab-ci.yml'), TestBlob.new('copying')]
       expect(repository.tree).to receive(:blobs).and_return(files)
@@ -583,7 +574,7 @@ describe Repository, models: true do
     end
 
     it 'returns nil for empty repository' do
-      expect(repository).to receive(:empty?).and_return(true)
+      allow(repository).to receive(:file_on_head).and_raise(Rugged::ReferenceError)
       expect(repository.gitlab_ci_yml).to be_nil
     end
   end
@@ -778,7 +769,6 @@ describe Repository, models: true do
         expect(repository).not_to receive(:expire_emptiness_caches)
         expect(repository).to     receive(:expire_branches_cache)
         expect(repository).to     receive(:expire_has_visible_content_cache)
-        expect(repository).to     receive(:expire_branch_count_cache)
 
         repository.update_branch_with_hooks(user, 'new-feature') { new_rev }
       end
@@ -797,7 +787,6 @@ describe Repository, models: true do
         expect(empty_repository).to receive(:expire_emptiness_caches)
         expect(empty_repository).to receive(:expire_branches_cache)
         expect(empty_repository).to receive(:expire_has_visible_content_cache)
-        expect(empty_repository).to receive(:expire_branch_count_cache)
 
         empty_repository.commit_file(user, 'CHANGELOG', 'Changelog!',
                                      'Updates file content', 'master', false)
@@ -915,34 +904,6 @@ describe Repository, models: true do
     end
   end
 
-  describe '#expire_cache' do
-    it 'expires all caches' do
-      expect(repository).to receive(:expire_branch_cache)
-
-      repository.expire_cache
-    end
-
-    it 'expires the caches for a specific branch' do
-      expect(repository).to receive(:expire_branch_cache).with('master')
-
-      repository.expire_cache('master')
-    end
-
-    it 'expires the emptiness caches for an empty repository' do
-      expect(repository).to receive(:empty?).and_return(true)
-      expect(repository).to receive(:expire_emptiness_caches)
-
-      repository.expire_cache
-    end
-
-    it 'does not expire the emptiness caches for a non-empty repository' do
-      expect(repository).to receive(:empty?).and_return(false)
-      expect(repository).not_to receive(:expire_emptiness_caches)
-
-      repository.expire_cache
-    end
-  end
-
   describe '#expire_root_ref_cache' do
     it 'expires the root reference cache' do
       repository.root_ref
@@ -1002,12 +963,23 @@ describe Repository, models: true do
   describe '#expire_emptiness_caches' do
     let(:cache) { repository.send(:cache) }
 
-    it 'expires the caches' do
+    it 'expires the caches for an empty repository' do
+      allow(repository).to receive(:empty?).and_return(true)
+
       expect(cache).to receive(:expire).with(:empty?)
       expect(repository).to receive(:expire_has_visible_content_cache)
 
       repository.expire_emptiness_caches
     end
+
+    it 'does not expire the cache for a non-empty repository' do
+      allow(repository).to receive(:empty?).and_return(false)
+
+      expect(cache).not_to receive(:expire).with(:empty?)
+      expect(repository).not_to receive(:expire_has_visible_content_cache)
+
+      repository.expire_emptiness_caches
+    end
   end
 
   describe :skip_merged_commit do
@@ -1119,24 +1091,12 @@ describe Repository, models: true do
         repository.before_delete
       end
 
-      it 'flushes the tag count cache' do
-        expect(repository).to receive(:expire_tag_count_cache)
-
-        repository.before_delete
-      end
-
       it 'flushes the branches cache' do
         expect(repository).to receive(:expire_branches_cache)
 
         repository.before_delete
       end
 
-      it 'flushes the branch count cache' do
-        expect(repository).to receive(:expire_branch_count_cache)
-
-        repository.before_delete
-      end
-
       it 'flushes the root ref cache' do
         expect(repository).to receive(:expire_root_ref_cache)
 
@@ -1161,36 +1121,18 @@ describe Repository, models: true do
         allow(repository).to receive(:exists?).and_return(true)
       end
 
-      it 'flushes the caches that depend on repository data' do
-        expect(repository).to receive(:expire_cache)
-
-        repository.before_delete
-      end
-
       it 'flushes the tags cache' do
         expect(repository).to receive(:expire_tags_cache)
 
         repository.before_delete
       end
 
-      it 'flushes the tag count cache' do
-        expect(repository).to receive(:expire_tag_count_cache)
-
-        repository.before_delete
-      end
-
       it 'flushes the branches cache' do
         expect(repository).to receive(:expire_branches_cache)
 
         repository.before_delete
       end
 
-      it 'flushes the branch count cache' do
-        expect(repository).to receive(:expire_branch_count_cache)
-
-        repository.before_delete
-      end
-
       it 'flushes the root ref cache' do
         expect(repository).to receive(:expire_root_ref_cache)
 
@@ -1221,8 +1163,9 @@ describe Repository, models: true do
 
   describe '#before_push_tag' do
     it 'flushes the cache' do
-      expect(repository).to receive(:expire_cache)
-      expect(repository).to receive(:expire_tag_count_cache)
+      expect(repository).to receive(:expire_statistics_caches)
+      expect(repository).to receive(:expire_emptiness_caches)
+      expect(repository).to receive(:expire_tags_cache)
 
       repository.before_push_tag
     end
@@ -1239,17 +1182,23 @@ describe Repository, models: true do
   describe '#after_import' do
     it 'flushes and builds the cache' do
       expect(repository).to receive(:expire_content_cache)
-      expect(repository).to receive(:build_cache)
+      expect(repository).to receive(:expire_tags_cache)
+      expect(repository).to receive(:expire_branches_cache)
 
       repository.after_import
     end
   end
 
   describe '#after_push_commit' do
-    it 'flushes the cache' do
-      expect(repository).to receive(:expire_cache).with('master', '123')
+    it 'expires statistics caches' do
+      expect(repository).to receive(:expire_statistics_caches).
+        and_call_original
+
+      expect(repository).to receive(:expire_branch_cache).
+        with('master').
+        and_call_original
 
-      repository.after_push_commit('master', '123')
+      repository.after_push_commit('master')
     end
   end
 
@@ -1301,7 +1250,8 @@ describe Repository, models: true do
 
   describe '#before_remove_tag' do
     it 'flushes the tag cache' do
-      expect(repository).to receive(:expire_tag_count_cache)
+      expect(repository).to receive(:expire_tags_cache).and_call_original
+      expect(repository).to receive(:expire_statistics_caches).and_call_original
 
       repository.before_remove_tag
     end
@@ -1319,23 +1269,23 @@ describe Repository, models: true do
     end
   end
 
-  describe '#expire_branch_count_cache' do
-    let(:cache) { repository.send(:cache) }
-
+  describe '#expire_branches_cache' do
     it 'expires the cache' do
-      expect(cache).to receive(:expire).with(:branch_count)
+      expect(repository).to receive(:expire_method_caches).
+        with(%i(branch_names branch_count)).
+        and_call_original
 
-      repository.expire_branch_count_cache
+      repository.expire_branches_cache
     end
   end
 
-  describe '#expire_tag_count_cache' do
-    let(:cache) { repository.send(:cache) }
-
+  describe '#expire_tags_cache' do
     it 'expires the cache' do
-      expect(cache).to receive(:expire).with(:tag_count)
+      expect(repository).to receive(:expire_method_caches).
+        with(%i(tag_names tag_count)).
+        and_call_original
 
-      repository.expire_tag_count_cache
+      repository.expire_tags_cache
     end
   end
 
@@ -1411,84 +1361,27 @@ describe Repository, models: true do
 
   describe '#avatar' do
     it 'returns nil if repo does not exist' do
-      expect(repository).to receive(:exists?).and_return(false)
+      expect(repository).to receive(:file_on_head).
+        and_raise(Rugged::ReferenceError)
 
       expect(repository.avatar).to eq(nil)
     end
 
     it 'returns the first avatar file found in the repository' do
-      expect(repository).to receive(:blob_at_branch).
-        with('master', 'logo.png').
-        and_return(true)
+      expect(repository).to receive(:file_on_head).
+        with(:avatar).
+        and_return(double(:tree, path: 'logo.png'))
 
       expect(repository.avatar).to eq('logo.png')
     end
 
     it 'caches the output' do
-      allow(repository).to receive(:blob_at_branch).
-        with('master', 'logo.png').
-        and_return(true)
-
-      expect(repository.avatar).to eq('logo.png')
-
-      expect(repository).not_to receive(:blob_at_branch)
-      expect(repository.avatar).to eq('logo.png')
-    end
-  end
-
-  describe '#expire_avatar_cache' do
-    let(:cache) { repository.send(:cache) }
-
-    before do
-      allow(repository).to receive(:cache).and_return(cache)
-    end
-
-    context 'without a branch or revision' do
-      it 'flushes the cache' do
-        expect(cache).to receive(:expire).with(:avatar)
-
-        repository.expire_avatar_cache
-      end
-    end
-
-    context 'with a branch' do
-      it 'does not flush the cache if the branch is not the default branch' do
-        expect(cache).not_to receive(:expire)
-
-        repository.expire_avatar_cache('cats')
-      end
-
-      it 'flushes the cache if the branch equals the default branch' do
-        expect(cache).to receive(:expire).with(:avatar)
-
-        repository.expire_avatar_cache(repository.root_ref)
-      end
-    end
-
-    context 'with a branch and revision' do
-      let(:commit) { double(:commit) }
-
-      before do
-        allow(repository).to receive(:commit).and_return(commit)
-      end
-
-      it 'does not flush the cache if the commit does not change any logos' do
-        diff = double(:diff, new_path: 'test.txt')
-
-        expect(commit).to receive(:raw_diffs).and_return([diff])
-        expect(cache).not_to receive(:expire)
-
-        repository.expire_avatar_cache(repository.root_ref, '123')
-      end
-
-      it 'flushes the cache if the commit changes any of the logos' do
-        diff = double(:diff, new_path: Repository::AVATAR_FILES[0])
-
-        expect(commit).to receive(:raw_diffs).and_return([diff])
-        expect(cache).to receive(:expire).with(:avatar)
+      expect(repository).to receive(:file_on_head).
+        with(:avatar).
+        once.
+        and_return(double(:tree, path: 'logo.png'))
 
-        repository.expire_avatar_cache(repository.root_ref, '123')
-      end
+      2.times { expect(repository.avatar).to eq('logo.png') }
     end
   end
 
@@ -1502,40 +1395,6 @@ describe Repository, models: true do
     end
   end
 
-  describe '#build_cache' do
-    let(:cache) { repository.send(:cache) }
-
-    it 'builds the caches if they do not already exist' do
-      cache_keys = repository.cache_keys + repository.cache_keys_for_branches_and_tags
-
-      expect(cache).to receive(:exist?).
-        exactly(cache_keys.length).
-        times.
-        and_return(false)
-
-      cache_keys.each do |key|
-        expect(repository).to receive(key)
-      end
-
-      repository.build_cache
-    end
-
-    it 'does not build any caches that already exist' do
-      cache_keys = repository.cache_keys + repository.cache_keys_for_branches_and_tags
-
-      expect(cache).to receive(:exist?).
-        exactly(cache_keys.length).
-        times.
-        and_return(true)
-
-      cache_keys.each do |key|
-        expect(repository).not_to receive(key)
-      end
-
-      repository.build_cache
-    end
-  end
-
   describe "#keep_around" do
     it "does not fail if we attempt to reference bad commit" do
       expect(repository.kept_around?('abc1234')).to be_falsey
@@ -1592,83 +1451,226 @@ describe Repository, models: true do
     end
   end
 
-  describe '#changelog', caching: true do
+  describe '#gitignore', caching: true do
     it 'returns and caches the output' do
       expect(repository).to receive(:file_on_head).
-        with(:changelog).
-        and_return(Gitlab::Git::Tree.new(path: 'CHANGELOG')).
+        with(:gitignore).
+        and_return(Gitlab::Git::Tree.new(path: '.gitignore')).
         once
 
       2.times do
-        expect(repository.changelog).to be_an_instance_of(Gitlab::Git::Tree)
+        expect(repository.gitignore).to be_an_instance_of(Gitlab::Git::Tree)
       end
     end
   end
 
-  describe '#license_blob', caching: true do
+  describe '#koding_yml', caching: true do
     it 'returns and caches the output' do
       expect(repository).to receive(:file_on_head).
-        with(:license).
-        and_return(Gitlab::Git::Tree.new(path: 'LICENSE')).
+        with(:koding).
+        and_return(Gitlab::Git::Tree.new(path: '.koding.yml')).
         once
 
       2.times do
-        expect(repository.license_blob).to be_an_instance_of(Gitlab::Git::Tree)
+        expect(repository.koding_yml).to be_an_instance_of(Gitlab::Git::Tree)
       end
     end
   end
 
-  describe '#license_key', caching: true do
-    it 'returns and caches the output' do
-      license = double(key: 'mit')
+  describe '#readme', caching: true do
+    context 'with a non-existing repository' do
+      it 'returns nil' do
+        expect(repository).to receive(:tree).with(:head).and_return(nil)
 
-      expect(Licensee).to receive(:license).
-        with(repository.path).
-        and_return(license).
-        once
+        expect(repository.readme).to be_nil
+      end
+    end
 
-      2.times do
-        expect(repository.license_key).to eq('mit')
+    context 'with an existing repository' do
+      it 'returns the README' do
+        expect(repository.readme).to be_an_instance_of(Gitlab::Git::Blob)
       end
     end
   end
 
-  describe '#gitignore', caching: true do
-    it 'returns and caches the output' do
-      expect(repository).to receive(:file_on_head).
-        with(:gitignore).
-        and_return(Gitlab::Git::Tree.new(path: '.gitignore')).
-        once
+  describe '#expire_statistics_caches' do
+    it 'expires the caches' do
+      expect(repository).to receive(:expire_method_caches).
+        with(%i(size commit_count))
 
-      2.times do
-        expect(repository.gitignore).to be_an_instance_of(Gitlab::Git::Tree)
+      repository.expire_statistics_caches
+    end
+  end
+
+  describe '#expire_method_caches' do
+    it 'expires the caches of the given methods' do
+      expect_any_instance_of(RepositoryCache).to receive(:expire).with(:readme)
+      expect_any_instance_of(RepositoryCache).to receive(:expire).with(:gitignore)
+
+      repository.expire_method_caches(%i(readme gitignore))
+    end
+  end
+
+  describe '#expire_all_method_caches' do
+    it 'expires the caches of all methods' do
+      expect(repository).to receive(:expire_method_caches).
+        with(Repository::CACHED_METHODS)
+
+      repository.expire_all_method_caches
+    end
+  end
+
+  describe '#expire_avatar_cache' do
+    it 'expires the cache' do
+      expect(repository).to receive(:expire_method_caches).with(%i(avatar))
+
+      repository.expire_avatar_cache
+    end
+  end
+
+  describe '#file_on_head' do
+    context 'with a non-existing repository' do
+      it 'returns nil' do
+        expect(repository).to receive(:tree).with(:head).and_return(nil)
+
+        expect(repository.file_on_head(:readme)).to be_nil
+      end
+    end
+
+    context 'with a repository that has no blobs' do
+      it 'returns nil' do
+        expect_any_instance_of(Tree).to receive(:blobs).and_return([])
+
+        expect(repository.file_on_head(:readme)).to be_nil
+      end
+    end
+
+    context 'with an existing repository' do
+      it 'returns a Gitlab::Git::Tree' do
+        expect(repository.file_on_head(:readme)).
+          to be_an_instance_of(Gitlab::Git::Tree)
       end
     end
   end
 
-  describe '#koding_yml', caching: true do
-    it 'returns and caches the output' do
-      expect(repository).to receive(:file_on_head).
-        with(:koding).
-        and_return(Gitlab::Git::Tree.new(path: '.koding.yml')).
-        once
+  describe '#head_tree' do
+    context 'with an existing repository' do
+      it 'returns a Tree' do
+        expect(repository.head_tree).to be_an_instance_of(Tree)
+      end
+    end
 
-      2.times do
-        expect(repository.koding_yml).to be_an_instance_of(Gitlab::Git::Tree)
+    context 'with a non-existing repository' do
+      it 'returns nil' do
+        expect(repository).to receive(:head_commit).and_return(nil)
+
+        expect(repository.head_tree).to be_nil
       end
     end
   end
 
-  describe '#gitlab_ci_yml', caching: true do
-    it 'returns and caches the output' do
-      expect(repository).to receive(:file_on_head).
-        with(:gitlab_ci).
-        and_return(Gitlab::Git::Tree.new(path: '.gitlab-ci.yml')).
-        once
+  describe '#tree' do
+    context 'using a non-existing repository' do
+      before do
+        allow(repository).to receive(:head_commit).and_return(nil)
+      end
 
-      2.times do
-        expect(repository.gitlab_ci_yml).to be_an_instance_of(Gitlab::Git::Tree)
+      it 'returns nil' do
+        expect(repository.tree(:head)).to be_nil
+      end
+
+      it 'returns nil when using a path' do
+        expect(repository.tree(:head, 'README.md')).to be_nil
+      end
+    end
+
+    context 'using an existing repository' do
+      it 'returns a Tree' do
+        expect(repository.tree(:head)).to be_an_instance_of(Tree)
+      end
+    end
+  end
+
+  describe '#size' do
+    context 'with a non-existing repository' do
+      it 'returns 0' do
+        expect(repository).to receive(:exists?).and_return(false)
+
+        expect(repository.size).to eq(0.0)
+      end
+    end
+
+    context 'with an existing repository' do
+      it 'returns the repository size as a Float' do
+        expect(repository.size).to be_an_instance_of(Float)
+      end
+    end
+  end
+
+  describe '#commit_count' do
+    context 'with a non-existing repository' do
+      it 'returns 0' do
+        expect(repository).to receive(:root_ref).and_return(nil)
+
+        expect(repository.commit_count).to eq(0)
+      end
+    end
+
+    context 'with an existing repository' do
+      it 'returns the commit count' do
+        expect(repository.commit_count).to be_an_instance_of(Fixnum)
+      end
+    end
+  end
+
+  describe '#cache_method_output', caching: true do
+    context 'with a non-existing repository' do
+      let(:value) do
+        repository.cache_method_output(:cats, fallback: 10) do
+          raise Rugged::ReferenceError
+        end
+      end
+
+      it 'returns a fallback value' do
+        expect(value).to eq(10)
+      end
+
+      it 'does not cache the data' do
+        value
+
+        expect(repository.instance_variable_defined?(:@cats)).to eq(false)
+        expect(repository.send(:cache).exist?(:cats)).to eq(false)
       end
     end
+
+    context 'with an existing repository' do
+      it 'caches the output' do
+        object = double
+
+        expect(object).to receive(:number).once.and_return(10)
+
+        2.times do
+          val = repository.cache_method_output(:cats) { object.number }
+
+          expect(val).to eq(10)
+        end
+
+        expect(repository.send(:cache).exist?(:cats)).to eq(true)
+        expect(repository.instance_variable_get(:@cats)).to eq(10)
+      end
+    end
+  end
+
+  describe '#refresh_method_caches' do
+    it 'refreshes the caches of the given types' do
+      expect(repository).to receive(:expire_method_caches).
+        with(%i(readme license_blob license_key))
+
+      expect(repository).to receive(:readme)
+      expect(repository).to receive(:license_blob)
+      expect(repository).to receive(:license_key)
+
+      repository.refresh_method_caches(%i(readme license))
+    end
   end
 end
diff --git a/spec/requests/api/branches_spec.rb b/spec/requests/api/branches_spec.rb
index 8f605757186..fe6b875b997 100644
--- a/spec/requests/api/branches_spec.rb
+++ b/spec/requests/api/branches_spec.rb
@@ -14,7 +14,7 @@ describe API::API, api: true  do
 
   describe "GET /projects/:id/repository/branches" do
     it "returns an array of project branches" do
-      project.repository.expire_cache
+      project.repository.expire_all_method_caches
 
       get api("/projects/#{project.id}/repository/branches", user)
       expect(response).to have_http_status(200)
diff --git a/spec/services/git_push_service_spec.rb b/spec/services/git_push_service_spec.rb
index 62f9982e840..9d7702f5c96 100644
--- a/spec/services/git_push_service_spec.rb
+++ b/spec/services/git_push_service_spec.rb
@@ -27,27 +27,14 @@ describe GitPushService, services: true do
 
       it { is_expected.to be_truthy }
 
-      it 'flushes general cached data' do
-        expect(project.repository).to receive(:expire_cache).
-          with('master', newrev)
+      it 'calls the after_push_commit hook' do
+        expect(project.repository).to receive(:after_push_commit).with('master')
 
         subject
       end
 
-      it 'flushes the visible content cache' do
-        expect(project.repository).to receive(:expire_has_visible_content_cache)
-
-        subject
-      end
-
-      it 'flushes the branches cache' do
-        expect(project.repository).to receive(:expire_branches_cache)
-
-        subject
-      end
-
-      it 'flushes the branch count cache' do
-        expect(project.repository).to receive(:expire_branch_count_cache)
+      it 'calls the after_create_branch hook' do
+        expect(project.repository).to receive(:after_create_branch)
 
         subject
       end
@@ -56,21 +43,8 @@ describe GitPushService, services: true do
     context 'existing branch' do
       it { is_expected.to be_truthy }
 
-      it 'flushes general cached data' do
-        expect(project.repository).to receive(:expire_cache).
-          with('master', newrev)
-
-        subject
-      end
-
-      it 'does not flush the branches cache' do
-        expect(project.repository).not_to receive(:expire_branches_cache)
-
-        subject
-      end
-
-      it 'does not flush the branch count cache' do
-        expect(project.repository).not_to receive(:expire_branch_count_cache)
+      it 'calls the after_push_commit hook' do
+        expect(project.repository).to receive(:after_push_commit).with('master')
 
         subject
       end
@@ -81,27 +55,14 @@ describe GitPushService, services: true do
 
       it { is_expected.to be_truthy }
 
-      it 'flushes the visible content cache' do
-        expect(project.repository).to receive(:expire_has_visible_content_cache)
-
-        subject
-      end
-
-      it 'flushes the branches cache' do
-        expect(project.repository).to receive(:expire_branches_cache)
-
-        subject
-      end
-
-      it 'flushes the branch count cache' do
-        expect(project.repository).to receive(:expire_branch_count_cache)
+      it 'calls the after_push_commit hook' do
+        expect(project.repository).to receive(:after_push_commit).with('master')
 
         subject
       end
 
-      it 'flushes general cached data' do
-        expect(project.repository).to receive(:expire_cache).
-          with('master', newrev)
+      it 'calls the after_remove_branch hook' do
+        expect(project.repository).to receive(:after_remove_branch)
 
         subject
       end
@@ -598,6 +559,51 @@ describe GitPushService, services: true do
     end
   end
 
+  describe '#update_caches' do
+    let(:service) do
+      described_class.new(project,
+                          user,
+                          oldrev: sample_commit.parent_id,
+                          newrev: sample_commit.id,
+                          ref: 'refs/heads/master')
+    end
+
+    context 'on the default branch' do
+      before do
+        allow(service).to receive(:is_default_branch?).and_return(true)
+      end
+
+      it 'flushes the caches of any special files that have been changed' do
+        commit = double(:commit)
+        diff = double(:diff, new_path: 'README.md')
+
+        expect(commit).to receive(:raw_diffs).with(deltas_only: true).
+          and_return([diff])
+
+        service.push_commits = [commit]
+
+        expect(ProjectCacheWorker).to receive(:perform_async).
+          with(project.id, %i(readme))
+
+        service.update_caches
+      end
+    end
+
+    context 'on a non-default branch' do
+      before do
+        allow(service).to receive(:is_default_branch?).and_return(false)
+      end
+
+      it 'does not flush any conditional caches' do
+        expect(ProjectCacheWorker).to receive(:perform_async).
+          with(project.id, []).
+          and_call_original
+
+        service.update_caches
+      end
+    end
+  end
+
   def execute_service(project, user, oldrev, newrev, ref)
     service = described_class.new(project, user, oldrev: oldrev, newrev: newrev, ref: ref )
     service.execute
diff --git a/spec/services/git_tag_push_service_spec.rb b/spec/services/git_tag_push_service_spec.rb
index 0879e3ab4c8..bd074b9bd71 100644
--- a/spec/services/git_tag_push_service_spec.rb
+++ b/spec/services/git_tag_push_service_spec.rb
@@ -18,7 +18,7 @@ describe GitTagPushService, services: true do
     end
 
     it 'flushes general cached data' do
-      expect(project.repository).to receive(:expire_cache)
+      expect(project.repository).to receive(:before_push_tag)
 
       subject
     end
@@ -28,12 +28,6 @@ describe GitTagPushService, services: true do
 
       subject
     end
-
-    it 'flushes the tag count cache' do
-      expect(project.repository).to receive(:expire_tag_count_cache)
-
-      subject
-    end
   end
 
   describe "Git Tag Push Data" do
diff --git a/spec/workers/project_cache_worker_spec.rb b/spec/workers/project_cache_worker_spec.rb
index bfa8c0ff2c6..855c28b584e 100644
--- a/spec/workers/project_cache_worker_spec.rb
+++ b/spec/workers/project_cache_worker_spec.rb
@@ -2,62 +2,78 @@ require 'spec_helper'
 
 describe ProjectCacheWorker do
   let(:project) { create(:project) }
+  let(:worker) { described_class.new }
 
-  subject { described_class.new }
-
-  describe '.perform_async' do
-    it 'schedules the job when no lease exists' do
-      allow_any_instance_of(Gitlab::ExclusiveLease).to receive(:exists?).
-        and_return(false)
+  describe '#perform' do
+    before do
+      allow_any_instance_of(Gitlab::ExclusiveLease).to receive(:try_obtain).
+        and_return(true)
+    end
 
-      expect_any_instance_of(described_class).to receive(:perform)
+    context 'with a non-existing project' do
+      it 'does nothing' do
+        expect(worker).not_to receive(:update_repository_size)
 
-      described_class.perform_async(project.id)
+        worker.perform(-1)
+      end
     end
 
-    it 'does not schedule the job when a lease exists' do
-      allow_any_instance_of(Gitlab::ExclusiveLease).to receive(:exists?).
-        and_return(true)
+    context 'with an existing project without a repository' do
+      it 'does nothing' do
+        allow_any_instance_of(Repository).to receive(:exists?).and_return(false)
 
-      expect_any_instance_of(described_class).not_to receive(:perform)
+        expect(worker).not_to receive(:update_repository_size)
 
-      described_class.perform_async(project.id)
+        worker.perform(project.id)
+      end
     end
-  end
 
-  describe '#perform' do
-    context 'when an exclusive lease can be obtained' do
-      before do
-        allow(subject).to receive(:try_obtain_lease_for).with(project.id).
-          and_return(true)
-      end
+    context 'with an existing project' do
+      it 'updates the repository size' do
+        expect(worker).to receive(:update_repository_size).and_call_original
 
-      it 'updates project cache data' do
-        expect_any_instance_of(Repository).to receive(:size)
-        expect_any_instance_of(Repository).to receive(:commit_count)
+        worker.perform(project.id)
+      end
 
-        expect_any_instance_of(Project).to receive(:update_repository_size)
-        expect_any_instance_of(Project).to receive(:update_commit_count)
+      it 'updates the commit count' do
+        expect_any_instance_of(Project).to receive(:update_commit_count).
+          and_call_original
 
-        subject.perform(project.id)
+        worker.perform(project.id)
       end
 
-      it 'handles missing repository data' do
-        expect_any_instance_of(Repository).to receive(:exists?).and_return(false)
-        expect_any_instance_of(Repository).not_to receive(:size)
+      it 'refreshes the method caches' do
+        expect_any_instance_of(Repository).to receive(:refresh_method_caches).
+          with(%i(readme)).
+          and_call_original
 
-        subject.perform(project.id)
+        worker.perform(project.id, %i(readme))
       end
     end
+  end
 
-    context 'when an exclusive lease can not be obtained' do
-      it 'does nothing' do
-        allow(subject).to receive(:try_obtain_lease_for).with(project.id).
+  describe '#update_repository_size' do
+    context 'when a lease could not be obtained' do
+      it 'does not update the repository size' do
+        allow(worker).to receive(:try_obtain_lease_for).
+          with(project.id, :update_repository_size).
           and_return(false)
 
-        expect(subject).not_to receive(:update_caches)
+        expect(project).not_to receive(:update_repository_size)
+
+        worker.update_repository_size(project)
+      end
+    end
+
+    context 'when a lease could be obtained' do
+      it 'updates the repository size' do
+        allow(worker).to receive(:try_obtain_lease_for).
+          with(project.id, :update_repository_size).
+          and_return(true)
+
+        expect(project).to receive(:update_repository_size).and_call_original
 
-        subject.perform(project.id)
+        worker.update_repository_size(project)
       end
     end
   end