parse containerid for a pid from cgroup as a hex chain

pkg/internal/helpers/container/container.go

@@ -25,12 +25,12 @@ type Info struct {
 }
 
 // A docker cgroup entry is a string like:
-// 0::/docker/<hex...>/kubelet.slice/kubelet-kubepods.slice/kubelet-kubepods-besteffort.slice/
-// kubelet-kubepods-besteffort-pod<hex...>.slice/cri-containerd-<hex...>.scope
+// GKE: /kubepods/burstable/pod4a163a05-439d-484b-8e53-2968bc15824f/cde6dfaf5007ed65aad2d6aed72af91b0f3d95813492f773286e29ae145d20f4
+// GKE-containerd: /kubepods/burstable/podb53dfa9e2dc9b890f7fadb2770857b03/bb959773d06ad1a07d469bced637bbc49b6f8573c493fd0548d7f5810eb3e5a8
+// EKS: /kubepods.slice/kubepods-burstable.slice/kubepods-burstable-poddde1244b_5bb5_4297_b544_85f3bc0d80bf.slice/cri-containerd-acb62391578595ec849d87d8556369cee7f935f0425097fd5f870df0e8aabd3c.scope
+// Containerd: /kubepods.slice/kubepods-burstable.slice/kubepods-burstable-pod7260904bbd08e72e4dff95d9fccd2ee8.slice/cri-containerd-d36686f9785534531160dc936aec9d711a26eb37f4fc7752a2ae27d0a24345c1.scope
 // where the last <hex...> chain is the container ID inside its Pod
-// The /docker/<hex...> part might not be visible inside the Pod (e.g. deploying Beyla
-// as a sidecar). That's why we search for the "kubelet.slice" string.
-var dockerCgroup = regexp.MustCompile(`^\d+:.*:.*/.*-([\da-fA-F]+)\.scope`)
+var dockerCgroup = regexp.MustCompile(`([0-9a-f]){64}`)
 
 // InfoForPID returns the container ID and PID namespace for the given PID.
 func InfoForPID(pid uint32) (Info, error) {
@@ -45,10 +45,10 @@ func InfoForPID(pid uint32) (Info, error) {
 	}
 	for _, cgroupEntry := range bytes.Split(cgroupBytes, []byte{'\n'}) {
 		submatches := dockerCgroup.FindSubmatch(cgroupEntry)
-		if len(submatches) < 2 {
+		if len(submatches) < 1 {
 			continue
 		}
-		return Info{PIDNamespace: ns, ContainerID: string(submatches[1])}, nil
+		return Info{PIDNamespace: ns, ContainerID: string(submatches[0])}, nil
 	}
 	return Info{}, fmt.Errorf("%s: couldn't find any docker entry for process with PID %d", cgroupFile, pid)
 }