fix(ebpf): prefer pid targets over container targets (#2761)

Author: korniltsev

ebpf/sd/procfs.go

@@ -8,9 +8,7 @@ import (
 
 var (
 	// cgroupContainerIDRe matches a container ID from a /proc/{pid}}/cgroup
-	// 12:cpuset:/kubepods.slice/kubepods-burstable.slice/kubepods-burstable-pod471203d1_984f_477e_9c35_db96487ffe5e.slice/cri-containerd-a534eb629135e43beb13213976e37bb2ab95cba4c0d1d0b4e27c6bc4d8091b83.scope"
-	// 11:devices:/kubepods/besteffort/pod85adbef3-622f-4ef2-8f60-a8bdf3eb6c72/7edda1de1e0d1d366351e478359cf5fa16bb8ab53063a99bb119e56971bfb7e2
-	cgroupContainerIDRe = regexp.MustCompile(`^.*/(?:.*-)?([0-9a-f]+)(?:\.|\s*$)`)
+	cgroupContainerIDRe = regexp.MustCompile(`^.*/(?:.*-)?([0-9a-f]{64})(?:\.|\s*$)`)
 )
 
 func (tf *targetFinder) getContainerIDFromPID(pid uint32) containerID {

ebpf/sd/target.go

@@ -181,16 +181,16 @@ func (tf *targetFinder) setTargets(opts TargetsOptions) {
 	containerID2Target := make(map[containerID]*Target)
 	pid2Target := make(map[uint32]*Target)
 	for _, target := range opts.Targets {
-		if cid := containerIDFromTarget(target); cid != "" {
-			t := NewTarget(cid, 0, target)
-			containerID2Target[cid] = t
-		} else if pid := pidFromTarget(target); pid != 0 {
+		if pid := pidFromTarget(target); pid != 0 {
 			t := NewTarget("", pid, target)
 			pid2Target[pid] = t
+		} else if cid := containerIDFromTarget(target); cid != "" {
+			t := NewTarget(cid, 0, target)
+			containerID2Target[cid] = t
 		}
 	}
-	if len(opts.Targets) > 0 && len(containerID2Target) == 0 {
-		_ = level.Warn(tf.l).Log("msg", "No container IDs found in targets")
+	if len(opts.Targets) > 0 && len(containerID2Target) == 0 && len(pid2Target) == 0 {
+		_ = level.Warn(tf.l).Log("msg", "No targets found")
 	}
 	tf.cid2target = containerID2Target
 	tf.pid2target = pid2Target

ebpf/sd/target_test.go

@@ -2,12 +2,13 @@ package sd
 
 import (
 	"fmt"
-	"github.com/grafana/pyroscope/ebpf/util"
 	"io/fs"
 	"os"
 	"path/filepath"
 	"testing"
 
+	"github.com/grafana/pyroscope/ebpf/util"
+
 	"github.com/stretchr/testify/require"
 )
 
@@ -49,6 +50,11 @@ func TestCGroupMatching(t *testing.T) {
 				"7edda1de1e0d1d366351e478359cf5fa16bb8ab53063a99bb119e56971bfb7e2",
 			expectedID: "7edda1de1e0d1d366351e478359cf5fa16bb8ab53063a99bb119e56971bfb7e2",
 		},
+		{
+			containerID: "",
+			cgroup:      "0::/../../user.slice/user-501.slice/session-3.scope",
+			expectedID:  "",
+		},
 	}
 	for i, tc := range testcases {
 		t.Run(fmt.Sprintf("testcase %d %s", i, tc.cgroup), func(t *testing.T) {
@@ -136,3 +142,44 @@ func TestTargetFinder(t *testing.T) {
 	target = tf.FindTarget(239)
 	require.Nil(t, target)
 }
+
+func TestPreferPIDOverContainerID(t *testing.T) {
+	fs, err := newMockFS()
+	require.NoError(t, err)
+	defer fs.rm()
+
+	options := TargetsOptions{
+		Targets: []DiscoveryTarget{
+			map[string]string{
+				"__meta_kubernetes_pod_container_id":   "containerd://9a7c72f122922fe3445ba85ce72c507c8976c0f3d919403fda7c22dfe516f66f",
+				"__meta_kubernetes_namespace":          "foo",
+				"__meta_kubernetes_pod_container_name": "bar",
+				"__process_pid__":                      "1801264",
+				"exe":                                  "/bin/bash",
+			},
+			map[string]string{
+				"__meta_kubernetes_pod_container_id":   "containerd://9a7c72f122922fe3445ba85ce72c507c8976c0f3d919403fda7c22dfe516f66f",
+				"__meta_kubernetes_namespace":          "foo",
+				"__meta_kubernetes_pod_container_name": "bar",
+				"__process_pid__":                      "1801265",
+				"exe":                                  "/bin/dash",
+			},
+		},
+		TargetsOnly:        true,
+		DefaultTarget:      nil,
+		ContainerCacheSize: 1024,
+	}
+
+	tf, err := NewTargetFinder(fs.root, util.TestLogger(t), options)
+	require.NoError(t, err)
+
+	target := tf.FindTarget(1801264)
+	require.NotNil(t, target)
+	require.Equal(t, "ebpf/foo/bar", target.labels.Get("service_name"))
+	require.Equal(t, "/bin/bash", target.labels.Get("exe"))
+
+	target = tf.FindTarget(1801265)
+	require.NotNil(t, target)
+	require.Equal(t, "ebpf/foo/bar", target.labels.Get("service_name"))
+	require.Equal(t, "/bin/dash", target.labels.Get("exe"))
+}