From d65442b1d9621da6749d59ea1a544a2ea39b3a79 Mon Sep 17 00:00:00 2001
From: GitLab Bot <gitlab-bot@gitlab.com>
Date: Thu, 23 Jan 2020 00:08:53 +0000
Subject: Add latest changes from gitlab-org/gitlab@master

---
 spec/lib/gitlab/database/migration_helpers_spec.rb |  13 ++
 spec/lib/gitlab/database/with_lock_retries_spec.rb | 131 +++++++++++++++++++++
 2 files changed, 144 insertions(+)
 create mode 100644 spec/lib/gitlab/database/with_lock_retries_spec.rb

(limited to 'spec/lib/gitlab/database')

diff --git a/spec/lib/gitlab/database/migration_helpers_spec.rb b/spec/lib/gitlab/database/migration_helpers_spec.rb
index e0b4c8ae1f7..f71d3a67eb9 100644
--- a/spec/lib/gitlab/database/migration_helpers_spec.rb
+++ b/spec/lib/gitlab/database/migration_helpers_spec.rb
@@ -1518,4 +1518,17 @@ describe Gitlab::Database::MigrationHelpers do
       model.create_or_update_plan_limit('project_hooks', 'free', 10)
     end
   end
+
+  describe '#with_lock_retries' do
+    let(:buffer) { StringIO.new }
+    let(:in_memory_logger) { Gitlab::JsonLogger.new(buffer) }
+    let(:env) { { 'DISABLE_LOCK_RETRIES' => 'true' } }
+
+    it 'sets the migration class name in the logs' do
+      model.with_lock_retries(env: env, logger: in_memory_logger) { }
+
+      buffer.rewind
+      expect(buffer.read).to include("\"class\":\"#{model.class}\"")
+    end
+  end
 end
diff --git a/spec/lib/gitlab/database/with_lock_retries_spec.rb b/spec/lib/gitlab/database/with_lock_retries_spec.rb
new file mode 100644
index 00000000000..c3be6510584
--- /dev/null
+++ b/spec/lib/gitlab/database/with_lock_retries_spec.rb
@@ -0,0 +1,131 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::Database::WithLockRetries do
+  let(:env) { {} }
+  let(:logger) { Gitlab::Database::WithLockRetries::NULL_LOGGER }
+  let(:subject) { described_class.new(env: env, logger: logger, timing_configuration: timing_configuration) }
+
+  let(:timing_configuration) do
+    [
+      [1.second, 1.second],
+      [1.second, 1.second],
+      [1.second, 1.second],
+      [1.second, 1.second],
+      [1.second, 1.second]
+    ]
+  end
+
+  describe '#run' do
+    it 'requires block' do
+      expect { subject.run }.to raise_error(StandardError, 'no block given')
+    end
+
+    context 'when DISABLE_LOCK_RETRIES is set' do
+      let(:env) { { 'DISABLE_LOCK_RETRIES' => 'true' } }
+
+      it 'executes the passed block without retrying' do
+        object = double
+
+        expect(object).to receive(:method).once
+
+        subject.run { object.method }
+      end
+    end
+
+    context 'when lock retry is enabled' do
+      class ActiveRecordSecond < ActiveRecord::Base
+      end
+
+      let(:lock_fiber) do
+        Fiber.new do
+          # Initiating a second DB connection for the lock
+          conn = ActiveRecordSecond.establish_connection(Rails.configuration.database_configuration[Rails.env]).connection
+          conn.transaction do
+            conn.execute("LOCK TABLE #{Project.table_name} in exclusive mode")
+
+            Fiber.yield
+          end
+          ActiveRecordSecond.remove_connection # force disconnect
+        end
+      end
+
+      before do
+        lock_fiber.resume # start the transaction and lock the table
+      end
+
+      context 'lock_fiber' do
+        it 'acquires lock successfully' do
+          check_exclusive_lock_query = """
+            SELECT 1
+            FROM pg_locks l
+            JOIN pg_class t ON l.relation = t.oid
+            WHERE t.relkind = 'r' AND l.mode = 'ExclusiveLock' AND t.relname = '#{Project.table_name}'
+          """
+
+          expect(ActiveRecord::Base.connection.execute(check_exclusive_lock_query).to_a).to be_present
+        end
+      end
+
+      shared_examples 'retriable exclusive lock on `projects`' do
+        it 'succeeds executing the given block' do
+          lock_attempts = 0
+          lock_acquired = false
+
+          expect_any_instance_of(Gitlab::Database::WithLockRetries).to receive(:sleep).exactly(retry_count - 1).times # we don't sleep in the last iteration
+
+          allow_any_instance_of(Gitlab::Database::WithLockRetries).to receive(:run_block_with_transaction).and_wrap_original do |method|
+            lock_fiber.resume if lock_attempts == retry_count
+
+            method.call
+          end
+
+          subject.run do
+            lock_attempts += 1
+
+            if lock_attempts == retry_count # we reached the last retry iteration, if we kill the thread, the last try (no lock_timeout) will succeed)
+              lock_fiber.resume
+            end
+
+            ActiveRecord::Base.transaction do
+              ActiveRecord::Base.connection.execute("LOCK TABLE #{Project.table_name} in exclusive mode")
+              lock_acquired = true
+            end
+          end
+
+          expect(lock_attempts).to eq(retry_count)
+          expect(lock_acquired).to eq(true)
+        end
+      end
+
+      context 'after 3 iterations' do
+        let(:retry_count) { 4 }
+
+        it_behaves_like 'retriable exclusive lock on `projects`'
+      end
+
+      context 'after the retries, without setting lock_timeout' do
+        let(:retry_count) { timing_configuration.size }
+
+        it_behaves_like 'retriable exclusive lock on `projects`'
+      end
+
+      context 'when statement timeout is reached' do
+        it 'raises QueryCanceled error' do
+          lock_acquired = false
+          ActiveRecord::Base.connection.execute("SET LOCAL statement_timeout='100ms'")
+
+          expect do
+            subject.run do
+              ActiveRecord::Base.connection.execute("SELECT 1 FROM pg_sleep(0.11)") # 110ms
+              lock_acquired = true
+            end
+          end.to raise_error(ActiveRecord::QueryCanceled)
+
+          expect(lock_acquired).to eq(false)
+        end
+      end
+    end
+  end
+end
-- 
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