From 79c2fbc6e7e660eb5acb6f64646e457130d637fc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Mierzwa?= <l.mierzwa@gmail.com>
Date: Thu, 3 Jun 2021 12:38:57 +0100
Subject: [PATCH] feat(backend): use automaxprocs for GOMAXPROCS

---
 CHANGELOG.md      | 7 +++++++
 README.md         | 3 +++
 cmd/karma/main.go | 5 +++++
 go.mod            | 1 +
 go.sum            | 2 ++
 5 files changed, 18 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f1512f0e4..d9f70e1d0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,12 @@
 # Changelog
 
+## [unreleased]
+
+### Added
+
+- Use [uber-go/automaxprocs](https://github.com/uber-go/automaxprocs)
+  to automatically adjust `GOMAXPROCS` to match Linux container CPU quota.
+
 ## v0.86
 
 ### Added
diff --git a/README.md b/README.md
index 571a6914d..f76e820b7 100644
--- a/README.md
+++ b/README.md
@@ -262,6 +262,9 @@ Images are built automatically for:
 - release tags in git - `ghcr.io/prymitive/karma:vX.Y.Z`
 - main branch commits - `ghcr.io/prymitive/karma:latest`
 
+_NOTE_ karma uses [uber-go/automaxprocs](https://github.com/uber-go/automaxprocs)
+to automatically adjust `GOMAXPROCS` to match Linux container CPU quota.
+
 #### Examples
 
 To start a release image run:
diff --git a/cmd/karma/main.go b/cmd/karma/main.go
index 729f5a43d..00bf44839 100644
--- a/cmd/karma/main.go
+++ b/cmd/karma/main.go
@@ -25,6 +25,7 @@ import (
 	"github.com/prymitive/karma/internal/transform"
 	"github.com/prymitive/karma/internal/uri"
 	"github.com/prymitive/karma/ui"
+	"go.uber.org/automaxprocs/maxprocs"
 
 	"github.com/getsentry/sentry-go"
 	sentryhttp "github.com/getsentry/sentry-go/http"
@@ -454,6 +455,10 @@ func serve(errorHandling pflag.ErrorHandling) error {
 		return err
 	}
 
+	_, _ = maxprocs.Set(maxprocs.Logger(func(format string, v ...interface{}) {
+		log.Debug().Msgf(format, v)
+	}))
+
 	if config.Config.History.Enabled {
 		go historyPoller.run(config.Config.History.Workers)
 	}
diff --git a/go.mod b/go.mod
index a01153b1d..f068c9208 100644
--- a/go.mod
+++ b/go.mod
@@ -32,6 +32,7 @@ require (
 	github.com/rs/zerolog v1.22.0
 	github.com/spf13/pflag v1.0.5
 	go.mongodb.org/mongo-driver v1.5.2 // indirect
+	go.uber.org/automaxprocs v1.4.0
 	golang.org/x/net v0.0.0-20210525063256-abc453219eb5 // indirect
 	golang.org/x/sys v0.0.0-20210531080801-fdfd190a6549 // indirect
 	gopkg.in/go-playground/colors.v1 v1.2.0
diff --git a/go.sum b/go.sum
index 03a36daaf..8720be682 100644
--- a/go.sum
+++ b/go.sum
@@ -641,6 +641,8 @@ go.opencensus.io v0.20.2/go.mod h1:6WKK9ahsWS3RSO+PY9ZHZUfv2irvY6gN279GOPZjmmk=
 go.opencensus.io v0.22.2/go.mod h1:yxeiOL68Rb0Xd1ddK5vPZ/oVn4vY4Ynel7k9FzqtOIw=
 go.uber.org/atomic v1.3.2/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/atomic v1.5.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
+go.uber.org/automaxprocs v1.4.0 h1:CpDZl6aOlLhReez+8S3eEotD7Jx0Os++lemPlMULQP0=
+go.uber.org/automaxprocs v1.4.0/go.mod h1:/mTEdr7LvHhs0v7mjdxDreTz1OG5zdZGqgOnhWiR/+Q=
 go.uber.org/multierr v1.1.0/go.mod h1:wR5kodmAFQ0UK8QlbwjlSNy0Z68gJhDJUG5sjR94q/0=
 go.uber.org/multierr v1.3.0/go.mod h1:VgVr7evmIr6uPjLBxg28wmKNXyqE9akIJ5XnfpiKl+4=
 go.uber.org/tools v0.0.0-20190618225709-2cfd321de3ee/go.mod h1:vJERXedbb3MVM5f9Ejo0C68/HhF8uaILCdgjnY+goOA=