From 6cc7c1c91dafd3d2830406e99da5c8eb778db48a Mon Sep 17 00:00:00 2001
From: Aleksei Lipniagov <alipniagov@gitlab.com>
Date: Thu, 20 May 2021 16:37:14 +0300
Subject: [PATCH] Remove UnicornCheck service

Drops UnicornCheck.
Split from https://gitlab.com/gitlab-org/gitlab/-/merge_requests/61888.

Changelog: removed
---
 ...402-remove-unicorn-gitlab-health-check.yml |  5 ++
 lib/gitlab/health_checks/unicorn_check.rb     | 41 ------------
 lib/gitlab/metrics/exporter/web_exporter.rb   |  3 +-
 .../health_checks/unicorn_check_spec.rb       | 67 -------------------
 4 files changed, 6 insertions(+), 110 deletions(-)
 create mode 100644 changelogs/unreleased/330402-remove-unicorn-gitlab-health-check.yml
 delete mode 100644 lib/gitlab/health_checks/unicorn_check.rb
 delete mode 100644 spec/lib/gitlab/health_checks/unicorn_check_spec.rb

diff --git a/changelogs/unreleased/330402-remove-unicorn-gitlab-health-check.yml b/changelogs/unreleased/330402-remove-unicorn-gitlab-health-check.yml
new file mode 100644
index 00000000000000..4867f75652e473
--- /dev/null
+++ b/changelogs/unreleased/330402-remove-unicorn-gitlab-health-check.yml
@@ -0,0 +1,5 @@
+---
+title: Remove UnicornCheck service
+merge_request: 62204
+author:
+type: removed
diff --git a/lib/gitlab/health_checks/unicorn_check.rb b/lib/gitlab/health_checks/unicorn_check.rb
deleted file mode 100644
index f0c6fdab600aa7..00000000000000
--- a/lib/gitlab/health_checks/unicorn_check.rb
+++ /dev/null
@@ -1,41 +0,0 @@
-# frozen_string_literal: true
-
-module Gitlab
-  module HealthChecks
-    # This check can only be run on Unicorn `master` process
-    class UnicornCheck
-      extend SimpleAbstractCheck
-
-      class << self
-        include Gitlab::Utils::StrongMemoize
-
-        private
-
-        def metric_prefix
-          'unicorn_check'
-        end
-
-        def successful?(result)
-          result > 0
-        end
-
-        def check
-          return unless http_servers
-
-          http_servers.sum(&:worker_processes)
-        end
-
-        # Traversal of ObjectSpace is expensive, on fully loaded application
-        # it takes around 80ms. The instances of HttpServers are not a subject
-        # to change so we can cache the list of servers.
-        def http_servers
-          strong_memoize(:http_servers) do
-            next unless Gitlab::Runtime.unicorn?
-
-            ObjectSpace.each_object(::Unicorn::HttpServer).to_a
-          end
-        end
-      end
-    end
-  end
-end
diff --git a/lib/gitlab/metrics/exporter/web_exporter.rb b/lib/gitlab/metrics/exporter/web_exporter.rb
index 558454eaa1c0f9..756e6b0641a0c1 100644
--- a/lib/gitlab/metrics/exporter/web_exporter.rb
+++ b/lib/gitlab/metrics/exporter/web_exporter.rb
@@ -30,8 +30,7 @@ def initialize
           # application: https://gitlab.com/gitlab-org/gitlab/issues/35343
           self.readiness_checks = [
             WebExporter::ExporterCheck.new(self),
-            Gitlab::HealthChecks::PumaCheck,
-            Gitlab::HealthChecks::UnicornCheck
+            Gitlab::HealthChecks::PumaCheck
           ]
         end
 
diff --git a/spec/lib/gitlab/health_checks/unicorn_check_spec.rb b/spec/lib/gitlab/health_checks/unicorn_check_spec.rb
deleted file mode 100644
index 1cc44016002fd9..00000000000000
--- a/spec/lib/gitlab/health_checks/unicorn_check_spec.rb
+++ /dev/null
@@ -1,67 +0,0 @@
-# frozen_string_literal: true
-
-require 'spec_helper'
-
-RSpec.describe Gitlab::HealthChecks::UnicornCheck do
-  let(:result_class) { Gitlab::HealthChecks::Result }
-  let(:readiness) { described_class.readiness }
-  let(:metrics) { described_class.metrics }
-
-  before do
-    described_class.clear_memoization(:http_servers)
-  end
-
-  shared_examples 'with state' do |(state, message)|
-    it "does provide readiness" do
-      expect(readiness).to eq(result_class.new('unicorn_check', state, message))
-    end
-
-    it "does provide metrics" do
-      expect(metrics).to include(
-        an_object_having_attributes(name: 'unicorn_check_success', value: state ? 1 : 0))
-      expect(metrics).to include(
-        an_object_having_attributes(name: 'unicorn_check_latency_seconds', value: be >= 0))
-    end
-  end
-
-  context 'when Unicorn is not loaded' do
-    before do
-      allow(Gitlab::Runtime).to receive(:unicorn?).and_return(false)
-      hide_const('Unicorn')
-    end
-
-    it "does not provide readiness and metrics" do
-      expect(readiness).to be_nil
-      expect(metrics).to be_nil
-    end
-  end
-
-  context 'when Unicorn is loaded' do
-    let(:http_server_class) { Struct.new(:worker_processes) }
-
-    before do
-      allow(Gitlab::Runtime).to receive(:unicorn?).and_return(true)
-      stub_const('Unicorn::HttpServer', http_server_class)
-    end
-
-    context 'when no servers are running' do
-      it_behaves_like 'with state', [false, 'unexpected Unicorn check result: 0']
-    end
-
-    context 'when servers without workers are running' do
-      before do
-        http_server_class.new(0)
-      end
-
-      it_behaves_like 'with state', [false, 'unexpected Unicorn check result: 0']
-    end
-
-    context 'when servers with workers are running' do
-      before do
-        http_server_class.new(1)
-      end
-
-      it_behaves_like 'with state', true
-    end
-  end
-end
-- 
GitLab