Fix inconsistency in Redis performance bar statssh-fix-redis-performance-bar

peek-redis resets its counters at the start of an ActionController
notification (`start_processing.action_controller`), which causes it to
miss some Redis queries that precede it, such as the database load
balancer and Rack Attack queries. This produces inconsistencies in the
performance bar between the number of calls and their durations with the
actual calls in the detailed view.

We fix this by getting rid of peek-redis in favor of consolidating all
logic into the `RedisDetailed` view, which tracks Redis queries using
`RequestStore`. This has the nice property of removing thread-specific
counters as well.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/64707

5 files changed, 48 insertions, 34 deletions

diff --git a/Gemfile b/Gemfile
index 8bffc2a973d..de1f44642f2 100644
--- a/Gemfile
+++ b/Gemfile
@@ -299,7 +299,6 @@ gem 'peek-gc', '~> 0.0.2'
 gem 'peek-mysql2', '~> 1.2.0', group: :mysql
 gem 'peek-pg', '~> 1.3.0', group: :postgres
 gem 'peek-rblineprof', '~> 0.2.0'
-gem 'peek-redis', '~> 1.2.0'
 
 # Memory benchmarks
 gem 'derailed_benchmarks', require: false
diff --git a/Gemfile.lock b/Gemfile.lock
index 60939ae918c..2bcc3527de4 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -76,7 +76,6 @@ GEM
     asciidoctor-plantuml (0.0.9)
       asciidoctor (>= 1.5.6, < 3.0.0)
     ast (2.4.0)
-    atomic (1.1.99)
     attr_encrypted (3.1.0)
       encryptor (~> 3.0.0)
     attr_required (1.0.1)
@@ -658,10 +657,6 @@ GEM
     peek-rblineprof (0.2.0)
       peek
       rblineprof
-    peek-redis (1.2.0)
-      atomic (>= 1.0.0)
-      peek
-      redis
     pg (1.1.4)
     po_to_json (1.0.1)
       json (>= 1.6.0)
@@ -1199,7 +1194,6 @@ DEPENDENCIES
   peek-mysql2 (~> 1.2.0)
   peek-pg (~> 1.3.0)
   peek-rblineprof (~> 0.2.0)
-  peek-redis (~> 1.2.0)
   pg (~> 1.1)
   premailer-rails (~> 1.9.7)
   prometheus-client-mmap (~> 0.9.8)
diff --git a/config/initializers/peek.rb b/config/initializers/peek.rb
index d492b60705d..2aec32e878c 100644
--- a/config/initializers/peek.rb
+++ b/config/initializers/peek.rb
@@ -29,7 +29,7 @@ end
 Peek.into PEEK_DB_VIEW
 Peek.into Peek::Views::Gitaly
 Peek.into Peek::Views::Rblineprof
-Peek.into Peek::Views::Redis
+Peek.into Peek::Views::RedisDetailed
 Peek.into Peek::Views::GC
 Peek.into Peek::Views::Tracing if Labkit::Tracing.tracing_url_enabled?
 
diff --git a/lib/peek/views/redis.rb b/lib/peek/views/redis_detailed.rb
index 73de8672fa4..12760c9b75e 100644
--- a/lib/peek/views/redis.rb
+++ b/lib/peek/views/redis_detailed.rb
@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
 require 'redis'
-require 'peek-redis'
 
 module Gitlab
   module Peek
@@ -36,11 +35,42 @@ end
 
 module Peek
   module Views
-    module RedisDetailed
+    class RedisDetailed < View
       REDACTED_MARKER = "<redacted>"
 
+      def key
+        'redis'
+      end
+
       def results
-        super.merge(details: details)
+        {
+          calls: calls,
+          duration: formatted_duration,
+          details: details
+        }
+      end
+
+      def detail_store
+        ::Gitlab::SafeRequestStore['redis_call_details'] ||= []
+      end
+
+      private
+
+      def formatted_duration
+        ms = duration * 1000
+        if ms >= 1000
+          "%.2fms" % ms
+        else
+          "%.0fms" % ms
+        end
+      end
+
+      def duration
+        detail_store.map { |entry| entry[:duration] }.sum # rubocop:disable CodeReuse/ActiveRecord
+      end
+
+      def calls
+        detail_store.count
       end
 
       def details
@@ -49,10 +79,6 @@ module Peek
           .map(&method(:format_call_details))
       end
 
-      def detail_store
-        ::Gitlab::SafeRequestStore['redis_call_details'] ||= []
-      end
-
       def format_call_details(call)
         call.merge(cmd: format_command(call[:cmd]),
                    duration: (call[:duration] * 1000).round(3))
@@ -76,11 +102,3 @@ end
 class Redis::Client
   prepend Gitlab::Peek::RedisInstrumented
 end
-
-module Peek
-  module Views
-    class Redis < View
-      prepend Peek::Views::RedisDetailed
-    end
-  end
-end
diff --git a/spec/lib/peek/views/redis_detailed_spec.rb b/spec/lib/peek/views/redis_detailed_spec.rb
index da13b6df53b..61096e6c69e 100644
--- a/spec/lib/peek/views/redis_detailed_spec.rb
+++ b/spec/lib/peek/views/redis_detailed_spec.rb
@@ -2,14 +2,8 @@
 
 require 'spec_helper'
 
-describe Peek::Views::RedisDetailed do
-  let(:redis_detailed_class) do
-    Class.new do
-      include Peek::Views::RedisDetailed
-    end
-  end
-
-  subject { redis_detailed_class.new }
+describe Peek::Views::RedisDetailed, :request_store do
+  subject { described_class.new }
 
   using RSpec::Parameterized::TableSyntax
 
@@ -22,15 +16,24 @@ describe Peek::Views::RedisDetailed do
   end
 
   with_them do
-    it 'scrubs Redis commands', :request_store do
+    it 'scrubs Redis commands' do
       subject.detail_store << { cmd: cmd, duration: 1.second }
 
-      expect(subject.details.count).to eq(1)
-      expect(subject.details.first)
+      expect(subject.results[:details].count).to eq(1)
+      expect(subject.results[:details].first)
         .to eq({
                  cmd: expected,
                  duration: 1000
                })
     end
   end
+
+  it 'returns aggregated results' do
+    subject.detail_store << { cmd: [:get, 'test'], duration: 0.001 }
+    subject.detail_store << { cmd: [:get, 'test'], duration: 1.second }
+
+    expect(subject.results[:calls]).to eq(2)
+    expect(subject.results[:duration]).to eq('1001.00ms')
+    expect(subject.results[:details].count).to eq(2)
+  end
 end