Benchmarking for Banzai pipelines and filters

to be used during development

spec/benchmarks/banzai_benchmark.rb

+# frozen_string_literal: true
+
+if ENV.key?('BENCHMARK')
+  require 'spec_helper'
+  require 'erb'
+  require 'benchmark/ips'
+
+  # This benchmarks some of the Banzai pipelines and filters.
+  # They are not definitive, but can be used by a developer to
+  # get a rough idea how the changing or addition of a new filter
+  # will effect performance.
+  #
+  # Run by:
+  #   BENCHMARK=1 rspec spec/benchmarks/banzai_benchmark.rb
+  #
+  RSpec.describe 'GitLab Markdown Benchmark', :aggregate_failures do
+    include MarkupHelper
+
+    let_it_be(:feature)       { MarkdownFeature.new }
+    let_it_be(:project)       { feature.project }
+    let_it_be(:group)         { feature.group }
+    let_it_be(:wiki)          { feature.wiki }
+    let_it_be(:wiki_page)     { feature.wiki_page }
+    let_it_be(:markdown_text) { feature.raw_markdown }
+
+    let!(:render_context) { Banzai::RenderContext.new(project, current_user) }
+
+    before do
+      stub_application_setting(asset_proxy_enabled: true)
+      stub_application_setting(asset_proxy_secret_key: 'shared-secret')
+      stub_application_setting(asset_proxy_url: 'https://assets.example.com')
+      stub_application_setting(asset_proxy_whitelist: %w(gitlab.com *.mydomain.com))
+
+      Banzai::Filter::AssetProxyFilter.initialize_settings
+    end
+
+    context 'pipelines' do
+      it 'benchmarks several pipelines' do
+        path = 'images/example.jpg'
+        gitaly_wiki_file = Gitlab::GitalyClient::WikiFile.new(path: path)
+        allow(wiki).to receive(:find_file).with(path).and_return(Gitlab::Git::WikiFile.new(gitaly_wiki_file))
+        allow(wiki).to receive(:wiki_base_path) { '/namespace1/gitlabhq/wikis' }
+
+        puts "\n--> Benchmarking Full, Wiki, and Plain pipelines\n"
+
+        Benchmark.ips do |x|
+          x.config(time: 10, warmup: 2)
+
+          x.report('Full pipeline') { markdown(markdown_text, { pipeline: :full }) }
+          x.report('Wiki pipeline') { markdown(markdown_text, { pipeline: :wiki, wiki: wiki, page_slug: wiki_page.slug }) }
+          x.report('Plain pipeline') { markdown(markdown_text, { pipeline: :plain_markdown }) }
+
+          x.compare!
+        end
+      end
+    end
+
+    context 'filters' do
+      let(:context) do
+        tmp = { project: project, current_user: current_user, render_context: render_context }
+        Banzai::Filter::AssetProxyFilter.transform_context(tmp)
+      end
+
+      it 'benchmarks all filters in the FullPipeline' do
+        benchmark_pipeline_filters(:full)
+      end
+
+      it 'benchmarks all filters in the PlainMarkdownPipeline' do
+        benchmark_pipeline_filters(:plain_markdown)
+      end
+    end
+
+    # build up the source text for each filter
+    def build_filter_text(pipeline, initial_text)
+      filter_source = {}
+      input_text    = initial_text
+
+      pipeline.filters.each do |filter_klass|
+        filter_source[filter_klass] = input_text
+
+        output = filter_klass.call(input_text, context)
+        input_text = output
+      end
+
+      filter_source
+    end
+
+    def benchmark_pipeline_filters(pipeline_type)
+      pipeline      = Banzai::Pipeline[pipeline_type]
+      filter_source = build_filter_text(pipeline, markdown_text)
+
+      puts "\n--> Benchmarking #{pipeline.name.demodulize} filters\n"
+
+      Benchmark.ips do |x|
+        x.config(time: 10, warmup: 2)
+
+        pipeline.filters.each do |filter_klass|
+          label = filter_klass.name.demodulize.delete_suffix('Filter').truncate(20)
+
+          x.report(label) { filter_klass.call(filter_source[filter_klass], context) }
+        end
+
+        x.compare!
+      end
+    end
+
+    # Fake a `current_user` helper
+    def current_user
+      feature.user
+    end
+  end
+end