From 102566032ae3b5c829a8096ab2524ade9edf46d2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?nils=20m=C3=A5s=C3=A9n?= <nils@piksel.se>
Date: Wed, 7 Sep 2022 14:59:26 +0200
Subject: [PATCH] add GetRunningContainerID

---
 pkg/container/cgroup_id.go | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 pkg/container/cgroup_id.go

diff --git a/pkg/container/cgroup_id.go b/pkg/container/cgroup_id.go
new file mode 100644
index 0000000..999026f
--- /dev/null
+++ b/pkg/container/cgroup_id.go
@@ -0,0 +1,24 @@
+package container
+
+import (
+	"fmt"
+	"os"
+	"regexp"
+
+	"github.com/containrrr/watchtower/pkg/types"
+)
+
+var dockerContainerPattern = regexp.MustCompile(`[0-9]+:.*:/docker/([a-f|0-9]{64})`)
+
+func GetRunningContainerID() (cid types.ContainerID, err error) {
+	file, err := os.ReadFile(fmt.Sprintf("/proc/%d/cgroup", os.Getpid()))
+	if err != nil {
+		return
+	}
+
+	matches := dockerContainerPattern.FindStringSubmatch(string(file))
+	if len(matches) < 2 {
+		return "", nil
+	}
+	return types.ContainerID(matches[1]), nil
+}