From 8924469660600193d5b253307670a5bbbe2742cb Mon Sep 17 00:00:00 2001
From: Nadia Santalla <nadia@santalla.io>
Date: Thu, 30 Jan 2025 13:43:39 +0100
Subject: [PATCH] feat: crocochrome: try to use choom to lower oom_score_adj,
 failing gracefully

---
 cmd/crocochrome/main.go | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/cmd/crocochrome/main.go b/cmd/crocochrome/main.go
index 634f440..fd83d6a 100644
--- a/cmd/crocochrome/main.go
+++ b/cmd/crocochrome/main.go
@@ -5,6 +5,8 @@ import (
 	"log/slog"
 	"net/http"
 	"os"
+	"os/exec"
+	"strconv"
 
 	"github.com/grafana/crocochrome"
 	crocohttp "github.com/grafana/crocochrome/http"
@@ -18,6 +20,20 @@ func main() {
 		Level: slog.LevelDebug,
 	}))
 
+	const oomScore = -500
+	if out, err := choom(oomScore); err != nil {
+		logger.Error(
+			"Error changing OOM score, assuming this is not a production environment and continuing anyway",
+			"err", err,
+			"choomOutput", string(out),
+		)
+	} else {
+		logger.Info(
+			"Main process OOM score adjusted successfully",
+			"oomScore", oomScore,
+		)
+	}
+
 	mux := http.NewServeMux()
 
 	registry := prometheus.NewRegistry()
@@ -56,3 +72,9 @@ func main() {
 		logger.Error("Setting up HTTP listener", "err", err)
 	}
 }
+
+// choom runs the choom helper (source included in this repo) to lower the current process OOM score.
+func choom(score int) ([]byte, error) {
+	choom := exec.Command("choom", strconv.Itoa(os.Getpid()), strconv.Itoa(score))
+	return choom.CombinedOutput()
+}