Generate gem size metrics in memory CI

This includes several changes:
  - Rename memory-static to generate-gems-size-metrics-static
  - Rename memory-static-objects to generate-gems-memory-metrics-static
  - Change generate-gems-size-metrics-static interface. The script now
    expect `bundle exec derailed bundle:mem` output as its input. The
    script output to stdout, or stderr for error message.
  - Change generate-gems-memory-metrics-static interface. The script now
    expect `bundle exec derailed bundle:objects` output as its input.
    The script output to stdout, or stderr for error message.
  - Generate gem size metrics. Script generate-gems-size-metrics-static
    extract each gem size from `bundle exec derailed bundle:mem` output.
    Save output to metrics file in format: 'gem_size_mb{name="zip"} 0.5'

.gitlab/ci/memory.gitlab-ci.yml

@@ -5,15 +5,15 @@ memory-static:
 
     # Loads each of gems in the Gemfile and checks how much memory they consume when they are required.
     # 'derailed_benchmarks' internally uses 'get_process_mem'
-    - scripts/memory-static 'tmp/memory_static_full_report.txt' 'tmp/memory_static_metrics.txt'
+    - bundle exec derailed bundle:mem > tmp/memory_bundle_mem.txt
+    - scripts/generate-gems-size-metrics-static tmp/memory_bundle_mem.txt >> 'tmp/memory_metrics.txt'
 
     # Outputs detailed information about objects created while gems are loaded.
     # 'derailed_benchmarks' internally uses 'memory_profiler'
-    - scripts/memory-static-objects 'tmp/memory_static_objects_full_report.txt' 'tmp/memory_static_metrics.txt'
+    - bundle exec derailed bundle:objects > tmp/memory_bundle_objects.txt
+    - scripts/generate-gems-memory-metrics-static tmp/memory_bundle_objects.txt >> 'tmp/memory_metrics.txt'
   artifacts:
     paths:
-      - tmp/memory_static_full_report.txt
-      - tmp/memory_static_objects_full_report.txt
-      - tmp/memory_static_metrics.txt
+      - tmp/memory_*.txt
     reports:
-      metrics: tmp/memory_static_metrics.txt
+      metrics: tmp/memory_metrics.txt

scripts/generate-gems-memory-metrics-static

+#!/usr/bin/env ruby
+
+abort "usage: #{__FILE__} <memory_bundle_objects_file_name>" unless ARGV.length == 1
+memory_bundle_objects_file_name = ARGV.first
+
+full_report = File.readlines(memory_bundle_objects_file_name)
+
+allocated_str = full_report[1]
+retained_str = full_report[2]
+allocated_stats = /Total allocated: (?<bytes>.*) bytes \((?<objects>.*) objects\)/.match(allocated_str)
+retained_stats = /Total retained: (?<bytes>.*) bytes \((?<objects>.*) objects\)/.match(retained_str)
+
+abort 'failed to process the benchmark output' unless allocated_stats && retained_stats
+
+puts "memory_static_objects_allocated_mb #{(allocated_stats[:bytes].to_f / (1024 * 1024)).round(1)}"
+puts "memory_static_objects_retained_mb #{(retained_stats[:bytes].to_f / (1024 * 1024)).round(1)}"
+puts "memory_static_objects_allocated_items #{allocated_stats[:objects]}"
+puts "memory_static_objects_retained_items #{retained_stats[:objects]}"

scripts/generate-gems-size-metrics-static

+#!/usr/bin/env ruby
+
+abort "usage: #{__FILE__} <memory_bundle_mem_file_name>" unless ARGV.length == 1
+memory_bundle_mem_file_name = ARGV.first
+
+full_report = File.readlines(memory_bundle_mem_file_name)
+
+def total_size(memory_bundle_mem_report)
+  stats = /TOP: (?<total_mibs_str>.*) MiB/.match(memory_bundle_mem_report.first)
+  abort 'failed to process the benchmark output' unless stats
+  "gem_total_size_mb #{stats[:total_mibs_str].to_f.round(1)}"
+end
+
+TOP_LEVEL_GEM_LOG_FORMAT = /^  (?<gem_name>\S.*):\s*(?<gem_size>\d[.\d]*)\s*MiB/.freeze
+def all_gems(memory_bundle_mem_report)
+  memory_bundle_mem_report.map do |line|
+    TOP_LEVEL_GEM_LOG_FORMAT.match(line)
+  end.compact
+end
+
+def gems_as_metrics(gems_match_data)
+  gems_match_data.map do |gem|
+    gem_name = gem[:gem_name]
+    gem_size_mb = gem[:gem_size].to_f.round(1)
+    "gem_size_mb{name=\"#{gem_name}\"} #{gem_size_mb}"
+  end
+end
+
+puts total_size(full_report)
+puts gems_as_metrics(all_gems(full_report)).sort(&:casecmp)

scripts/memory-static

-#!/usr/bin/env ruby
-
-require_relative '../lib/gitlab/popen'
-
-full_report_filename, metrics_filename = ARGV
-abort 'usage: memory-static <full_report_filename> <metrics_filename>' unless full_report_filename && metrics_filename
-
-full_report, status = Gitlab::Popen.popen(%w(bundle exec derailed bundle:mem))
-abort 'failed to execute the benchmark' unless status.zero?
-
-File.open(full_report_filename, 'w') do |f|
-  f.write(full_report)
-end
-
-stats = /TOP: (?<total_mibs_str>.*) MiB/.match(full_report.lines.first)
-abort 'failed to process the benchmark output' unless stats
-
-File.open(metrics_filename, 'a') do |f|
-  f.puts "memory_static_total_mb #{stats[:total_mibs_str].to_f.round(1)}"
-end

scripts/memory-static-objects

-#!/usr/bin/env ruby
-
-require_relative '../lib/gitlab/popen'
-
-full_report_filename, metrics_filename = ARGV
-abort 'usage: memory-static-objects <full_report_filename> <metrics_filename>' unless full_report_filename && metrics_filename
-
-full_report, status = Gitlab::Popen.popen(%w(bundle exec derailed bundle:objects))
-abort 'failed to execute the benchmark' unless status.zero?
-
-File.open(full_report_filename, 'w') do |f|
-  f.write(full_report)
-end
-
-allocated_str = full_report.lines[1]
-retained_str = full_report.lines[2]
-allocated_stats = /Total allocated: (?<bytes>.*) bytes \((?<objects>.*) objects\)/.match(allocated_str)
-retained_stats = /Total retained: (?<bytes>.*) bytes \((?<objects>.*) objects\)/.match(retained_str)
-
-abort 'failed to process the benchmark output' unless allocated_stats && retained_stats
-
-File.open(metrics_filename, 'a') do |f|
-  f.puts "memory_static_objects_allocated_mb #{(allocated_stats[:bytes].to_f / (1024 * 1024)).round(1)}"
-  f.puts "memory_static_objects_retained_mb #{(retained_stats[:bytes].to_f / (104 * 1024)).round(1)}"
-  f.puts "memory_static_objects_allocated_items #{allocated_stats[:objects]}"
-  f.puts "memory_static_objects_retained_items #{retained_stats[:objects]}"
-end