Track ongoing pushes and reject mv-storage commands if there are push running (after waiting some time)mv-storage

8 files changed, 162 insertions, 4 deletions

diff --git a/CHANGELOG b/CHANGELOG
index 95a348f..7ac7895 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,4 +1,5 @@
 v3.3.0
+  - Track ongoing push commands
   - Add command to move repositories between repository storages
 
 v3.2.1
diff --git a/hooks/pre-receive b/hooks/pre-receive
index 66cb97d..09fa42b 100755
--- a/hooks/pre-receive
+++ b/hooks/pre-receive
@@ -9,10 +9,16 @@ protocol = ENV.delete('GL_PROTOCOL')
 repo_path = Dir.pwd
 
 require_relative '../lib/gitlab_custom_hook'
+require_relative '../lib/gitlab_reference_counter'
 require_relative '../lib/gitlab_access'
 
+# It's important that on pre-receive `increase_reference_counter` gets executed
+# last so that it only runs if everything else succeeded. On post-receive on the
+# other hand, we run GitlabPostReceive first because the push is already done
+# and we don't want to skip it if the custom hook fails.
 if GitlabAccess.new(repo_path, key_id, refs, protocol).exec &&
-    GitlabCustomHook.new.pre_receive(refs, repo_path)
+    GitlabCustomHook.new.pre_receive(refs, repo_path) &&
+    GitlabReferenceCounter.new(repo_path).increase
   exit 0
 else
   exit 1
diff --git a/lib/gitlab_post_receive.rb b/lib/gitlab_post_receive.rb
index ebcf317..7874c85 100644
--- a/lib/gitlab_post_receive.rb
+++ b/lib/gitlab_post_receive.rb
@@ -1,5 +1,6 @@
 require_relative 'gitlab_init'
 require_relative 'gitlab_net'
+require_relative 'gitlab_reference_counter'
 require 'json'
 require 'base64'
 require 'securerandom'
@@ -28,7 +29,7 @@ class GitlabPostReceive
       nil
     end
 
-    result
+    result && GitlabReferenceCounter.new(repo_path).decrease
   end
 
   protected
diff --git a/lib/gitlab_projects.rb b/lib/gitlab_projects.rb
index 0f643b0..a40cc4f 100644
--- a/lib/gitlab_projects.rb
+++ b/lib/gitlab_projects.rb
@@ -4,6 +4,7 @@ require 'open3'
 
 require_relative 'gitlab_config'
 require_relative 'gitlab_logger'
+require_relative 'gitlab_reference_counter'
 
 class GitlabProjects
   GLOBAL_HOOKS_DIRECTORY = File.join(ROOT_PATH, 'hooks')
@@ -313,8 +314,13 @@ class GitlabProjects
     # contents of the directory, as opposed to copying the directory by name
     source_path = File.join(full_path, '')
 
-    $logger.info "Syncing project #{@project_name} from <#{full_path}> to <#{new_full_path}>."
-    system(*%W(rsync -a #{source_path} #{new_full_path}))
+    if wait_for_pushes
+      $logger.info "Syncing project #{@project_name} from <#{full_path}> to <#{new_full_path}>."
+      system(*%W(rsync -a --delete #{source_path} #{new_full_path}))
+    else
+      $logger.error "mv-storage failed: source path <#{full_path}> is waiting for pushes to finish."
+      false
+    end
   end
 
   def fork_project
@@ -361,4 +367,18 @@ class GitlabProjects
     cmd = %W(git --git-dir=#{full_path} gc)
     system(*cmd)
   end
+
+  def wait_for_pushes
+    # Try for 30 seconds, polling every 10
+    3.times do
+      return true if gitlab_reference_counter.value == 0
+      sleep 10
+    end
+
+    false
+  end
+
+  def gitlab_reference_counter
+    @gitlab_reference_counter ||= GitlabReferenceCounter.new(full_path)
+  end
 end
diff --git a/lib/gitlab_reference_counter.rb b/lib/gitlab_reference_counter.rb
new file mode 100644
index 0000000..dc08f42
--- /dev/null
+++ b/lib/gitlab_reference_counter.rb
@@ -0,0 +1,52 @@
+require_relative 'gitlab_init'
+require_relative 'gitlab_net'
+
+class GitlabReferenceCounter
+  REFERENCE_EXPIRE_TIME = 600
+
+  attr_reader :path, :key
+
+  def initialize(path)
+    @path = path
+    @key = "git-receive-pack-reference-counter:#{path}"
+  end
+
+  def value
+    (redis_client.get(key) || 0).to_i
+  end
+
+  def increase
+    redis_cmd do
+      redis_client.incr(key)
+      redis_client.expire(key, REFERENCE_EXPIRE_TIME)
+    end
+  end
+
+  def decrease
+    redis_cmd do
+      current_value = redis_client.decr(key)
+      if current_value < 0
+        $logger.warn "Reference counter for #{path} decreased when its value was less than 1. Reseting the counter."
+        redis_client.del(key)
+      end
+    end
+  end
+
+  private
+
+  def redis_client
+    @redis_client ||= GitlabNet.new.redis_client
+  end
+
+  def redis_cmd
+    begin
+      yield
+      true
+    rescue => e
+      message = "GitLab: An unexpected error occurred in writing to Redis: #{e}"
+      $stderr.puts message
+      $logger.error message
+      false
+    end
+  end
+end
diff --git a/spec/gitlab_post_receive_spec.rb b/spec/gitlab_post_receive_spec.rb
index 26b1037..6762d49 100644
--- a/spec/gitlab_post_receive_spec.rb
+++ b/spec/gitlab_post_receive_spec.rb
@@ -25,6 +25,11 @@ describe GitlabPostReceive do
 
     before do
       allow_any_instance_of(GitlabNet).to receive(:redis_client).and_return(redis_client)
+      allow_any_instance_of(GitlabReferenceCounter).to receive(:redis_client).and_return(redis_client)
+      allow(redis_client).to receive(:get).and_return(1)
+      allow(redis_client).to receive(:incr).and_return(true)
+      allow(redis_client).to receive(:decr).and_return(0)
+      allow(redis_client).to receive(:rpush).and_return(true)
     end
 
     it "prints the broadcast message" do
@@ -59,6 +64,34 @@ describe GitlabPostReceive do
       gitlab_post_receive.exec
     end
 
+    context 'reference counter' do
+      it 'decreases the reference counter for the project' do
+        expect_any_instance_of(GitlabReferenceCounter).to receive(:decrease).and_return(true)
+
+        gitlab_post_receive.exec
+      end
+
+      context "when the redis command succeeds" do
+        before do
+          allow(redis_client).to receive(:decr).and_return(0)
+        end
+
+        it "returns true" do
+          expect(gitlab_post_receive.exec).to eq(true)
+        end
+      end
+
+      context "when the redis command fails" do
+        before do
+          allow(redis_client).to receive(:decr).and_raise('Fail')
+        end
+
+        it "returns false" do
+          expect(gitlab_post_receive.exec).to eq(false)
+        end
+      end
+    end
+
     context "when the redis command succeeds" do
 
       before do
diff --git a/spec/gitlab_projects_spec.rb b/spec/gitlab_projects_spec.rb
index 5e50af0..19646e3 100644
--- a/spec/gitlab_projects_spec.rb
+++ b/spec/gitlab_projects_spec.rb
@@ -213,6 +213,7 @@ describe GitlabProjects do
     before do
       FileUtils.mkdir_p(tmp_repo_path)
       FileUtils.mkdir_p(alternative_storage_path)
+      allow_any_instance_of(GitlabReferenceCounter).to receive(:value).and_return(0)
     end
 
     after { FileUtils.rm_rf(alternative_storage_path) }
@@ -235,6 +236,12 @@ describe GitlabProjects do
       bad_source.exec.should be_false
     end
 
+    it "should fail if there are pushes ongoing" do
+      allow_any_instance_of(GitlabReferenceCounter).to receive(:value).and_return(1)
+      $logger.should_receive(:error).with("mv-storage failed: source path <#{tmp_repo_path}> is waiting for pushes to finish.")
+      gl_projects.exec.should be_false
+    end
+
     it "should log an mv-storage event" do
       message = "Syncing project #{repo_name} from <#{tmp_repo_path}> to <#{new_repo_path}>."
       $logger.should_receive(:info).with(message)
diff --git a/spec/gitlab_reference_counter_spec.rb b/spec/gitlab_reference_counter_spec.rb
new file mode 100644
index 0000000..5be53ff
--- /dev/null
+++ b/spec/gitlab_reference_counter_spec.rb
@@ -0,0 +1,38 @@
+# coding: utf-8
+require 'spec_helper'
+require 'gitlab_reference_counter'
+
+describe GitlabReferenceCounter do
+  let(:redis_client) { double('redis_client') }
+  let(:reference_counter_key) { "git-receive-pack-reference-counter:/test/path" }
+  let(:gitlab_reference_counter) { GitlabReferenceCounter.new('/test/path') }
+
+  before do
+    allow(gitlab_reference_counter).to receive(:redis_client).and_return(redis_client)
+    $logger = double('logger').as_null_object
+  end
+
+  it 'increases and set the expire time of a reference count for a path' do
+    expect(redis_client).to receive(:incr).with(reference_counter_key)
+    expect(redis_client).to receive(:expire).with(reference_counter_key, GitlabReferenceCounter::REFERENCE_EXPIRE_TIME)
+    expect(gitlab_reference_counter.increase).to be(true)
+  end
+
+  it 'decreases the reference count for a path' do
+    allow(redis_client).to receive(:decr).and_return(0)
+    expect(redis_client).to receive(:decr).with(reference_counter_key)
+    expect(gitlab_reference_counter.decrease).to be(true)
+  end
+
+  it 'warns if attempting to decrease a counter with a value of one or less, and resets the counter' do
+    expect(redis_client).to receive(:decr).and_return(-1)
+    expect(redis_client).to receive(:del)
+    expect($logger).to receive(:warn).with("Reference counter for /test/path decreased when its value was less than 1. Reseting the counter.")
+    expect(gitlab_reference_counter.decrease).to be(true)
+  end
+
+  it 'get the reference count for a path' do
+    allow(redis_client).to receive(:get).and_return(1)
+    expect(gitlab_reference_counter.value).to be(1)
+  end
+end