Add cgroup v2 support for container id detector

CHANGELOG.md

@@ -30,6 +30,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
   These additions are replacements for the `Instrument` and `InstrumentKind` types from `go.opentelemetry.io/otel/sdk/metric/view`. (#3459)
 - The `Stream` type is added to `go.opentelemetry.io/otel/sdk/metric` to define a metric data stream a view will produce. (#3459)
 - The `AssertHasAttributes` allows instrument authors to test that datapoints returned have appropriate attributes. (#3487)
+- The `"go.opentelemetry.io/otel/sdk/resource".WithContainer` and `"go.opentelemetry.io/otel/sdk/resource".WithContainerID` support the cgoupv2 files. (#3508)
 
 ### Changed
 

sdk/resource/container.go

@@ -20,22 +20,20 @@ import (
 	"errors"
 	"io"
 	"os"
-	"regexp"
 
 	semconv "go.opentelemetry.io/otel/semconv/v1.12.0"
 )
 
 type containerIDProvider func() (string, error)
 
 var (
-	containerID         containerIDProvider = getContainerIDFromCGroup
-	cgroupContainerIDRe                     = regexp.MustCompile(`^.*/(?:.*-)?([0-9a-f]+)(?:\.|\s*$)`)
+	containerID                 containerIDProvider = getContainerIDFromCGroup
+	cgroupV1ContainerIDProvider containerIDProvider = getContainerIDFromCGroupV1
+	cgroupV2ContainerIDProvider containerIDProvider = getContainerIDFromCGroupV2
 )
 
 type cgroupContainerIDDetector struct{}
 
-const cgroupPath = "/proc/self/cgroup"
-
 // Detect returns a *Resource that describes the id of the container.
 // If no container id found, an empty resource will be returned.
 func (cgroupContainerIDDetector) Detect(ctx context.Context) (*Resource, error) {
@@ -61,8 +59,26 @@ var (
 )
 
 // getContainerIDFromCGroup returns the id of the container from the cgroup file.
+// If cgroup v1 container id provider fails, then fall back to cgroup v2 container id provider.
 // If no container id found, an empty string will be returned.
 func getContainerIDFromCGroup() (string, error) {
+	containerID, err := cgroupV1ContainerIDProvider()
+	if err != nil {
+		return "", err
+	}
+
+	if containerID == "" {
+		// Fallback to cgroup v2
+		containerID, err = cgroupV2ContainerIDProvider()
+		if err != nil {
+			return "", err
+		}
+	}
+
+	return containerID, nil
+}
+
+func getContainerIDFromCGroupFile(cgroupPath string, extractor func(string) string) (string, error) {
 	if _, err := osStat(cgroupPath); errors.Is(err, os.ErrNotExist) {
 		// File does not exist, skip
 		return "", nil
@@ -74,27 +90,18 @@ func getContainerIDFromCGroup() (string, error) {
 	}
 	defer file.Close()
 
-	return getContainerIDFromReader(file), nil
+	return getContainerIDFromReader(file, extractor), nil
 }
 
 // getContainerIDFromReader returns the id of the container from reader.
-func getContainerIDFromReader(reader io.Reader) string {
+func getContainerIDFromReader(reader io.Reader, extractor func(string) string) string {
 	scanner := bufio.NewScanner(reader)
 	for scanner.Scan() {
 		line := scanner.Text()
 
-		if id := getContainerIDFromLine(line); id != "" {
+		if id := extractor(line); id != "" {
 			return id
 		}
 	}
 	return ""
 }
-
-// getContainerIDFromLine returns the id of the container from one string line.
-func getContainerIDFromLine(line string) string {
-	matches := cgroupContainerIDRe.FindStringSubmatch(line)
-	if len(matches) <= 1 {
-		return ""
-	}
-	return matches[1]
-}

sdk/resource/container_id_cgroup_v1.go

@@ -0,0 +1,36 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+import (
+	"regexp"
+)
+
+const cgroupV1Path = "/proc/self/cgroup"
+
+var cgroupV1ContainerIDRe = regexp.MustCompile(`^.*/(?:.*-)?([0-9a-f]+)(?:\.|\s*$)`)
+
+func getContainerIDFromCGroupV1() (string, error) {
+	return getContainerIDFromCGroupFile(cgroupV1Path, getContainerIDFromCgroupV1Line)
+}
+
+// getContainerIDFromCgroupV1Line returns the id of the container from one string line.
+func getContainerIDFromCgroupV1Line(line string) string {
+	matches := cgroupV1ContainerIDRe.FindStringSubmatch(line)
+	if len(matches) <= 1 {
+		return ""
+	}
+	return matches[1]
+}

sdk/resource/container_id_cgroup_v1_test.go

@@ -0,0 +1,69 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetContainerIDFromCgroupV1Line(t *testing.T) {
+	testCases := []struct {
+		name                string
+		line                string
+		expectedContainerID string
+	}{
+		{
+			name:                "with suffix",
+			line:                "13:name=systemd:/podruntime/docker/kubepods/ac679f8a8319c8cf7d38e1adf263bc08d23.aaaa",
+			expectedContainerID: "ac679f8a8319c8cf7d38e1adf263bc08d23",
+		},
+		{
+			name:                "with prefix and suffix",
+			line:                "13:name=systemd:/podruntime/docker/kubepods/crio-dc679f8a8319c8cf7d38e1adf263bc08d23.stuff",
+			expectedContainerID: "dc679f8a8319c8cf7d38e1adf263bc08d23",
+		},
+		{
+			name:                "no prefix and suffix",
+			line:                "13:name=systemd:/pod/d86d75589bf6cc254f3e2cc29debdf85dde404998aa128997a819ff991827356",
+			expectedContainerID: "d86d75589bf6cc254f3e2cc29debdf85dde404998aa128997a819ff991827356",
+		},
+		{
+			name:                "with space",
+			line:                " 13:name=systemd:/pod/d86d75589bf6cc254f3e2cc29debdf85dde404998aa128997a819ff991827356 ",
+			expectedContainerID: "d86d75589bf6cc254f3e2cc29debdf85dde404998aa128997a819ff991827356",
+		},
+		{
+			name: "invalid hex string",
+			line: "13:name=systemd:/podruntime/docker/kubepods/ac679f8a8319c8cf7d38e1adf263bc08d23zzzz",
+		},
+		{
+			name: "no container id - 1",
+			line: "pids: /",
+		},
+		{
+			name: "no container id - 2",
+			line: "pids: ",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			containerID := getContainerIDFromCgroupV1Line(tc.line)
+			assert.Equal(t, tc.expectedContainerID, containerID)
+		})
+	}
+}

sdk/resource/container_id_cgroup_v2.go

@@ -0,0 +1,36 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+import (
+	"regexp"
+)
+
+const cgroupV2Path = "/proc/self/mountinfo"
+
+var cgroupV2ContainerIDRe = regexp.MustCompile(`.*/docker/containers/([0-9a-f]{64})/.*`)
+
+func getContainerIDFromCGroupV2() (string, error) {
+	return getContainerIDFromCGroupFile(cgroupV2Path, getContainerIDFromCgroupV2Line)
+}
+
+// getContainerIDFromCgroupV2Line returns the id of the container from one string line.
+func getContainerIDFromCgroupV2Line(line string) string {
+	matches := cgroupV2ContainerIDRe.FindStringSubmatch(line)
+	if len(matches) <= 1 {
+		return ""
+	}
+	return matches[1]
+}

sdk/resource/container_id_cgroup_v2_test.go

@@ -0,0 +1,64 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetContainerIDFromCgroupV2Line(t *testing.T) {
+	testCases := []struct {
+		name                string
+		line                string
+		expectedContainerID string
+	}{
+		{
+			name: "empty - 1",
+			line: "456 375 0:143 / / rw,relatime master:175 - overlay overlay rw,lowerdir=/var/lib/docker/overlay2/l/37L57D2IM7MEWLVE2Q2ECNDT67:/var/lib/docker/overlay2/l/46FCA2JFPCSNFGAR5TSYLLNHLK,upperdir=/var/lib/docker/overlay2/4e82c300793d703c19bdf887bfdad8b0354edda884ea27a8a2df89ab292719a4/diff,workdir=/var/lib/docker/overlay2/4e82c300793d703c19bdf887bfdad8b0354edda884ea27a8a2df89ab292719a4/work",
+		},
+		{
+			name: "empty - 2",
+			line: "457 456 0:146 / /proc rw,nosuid,nodev,noexec,relatime - proc proc rw",
+		},
+		{
+			name: "empty - 3",
+			line: "383 457 0:147 /null /proc/kcore rw,nosuid - tmpfs tmpfs rw,size=65536k,mode=755",
+		},
+		{
+			name:                "resolv.conf",
+			line:                "472 456 254:1 /docker/containers/dc64b5743252dbaef6e30521c34d6bbd1620c8ce65bdb7bf9e7143b61bb5b183/resolv.conf /etc/resolv.conf rw,relatime - ext4 /dev/vda1 rw",
+			expectedContainerID: "dc64b5743252dbaef6e30521c34d6bbd1620c8ce65bdb7bf9e7143b61bb5b183",
+		},
+		{
+			name:                "hostname",
+			line:                "473 456 254:1 /docker/containers/dc64b5743252dbaef6e30521c34d6bbd1620c8ce65bdb7bf9e7143b61bb5b183/hostname /etc/hostname rw,relatime - ext4 /dev/vda1 rw",
+			expectedContainerID: "dc64b5743252dbaef6e30521c34d6bbd1620c8ce65bdb7bf9e7143b61bb5b183",
+		},
+		{
+			name:                "host",
+			line:                "474 456 254:1 /docker/containers/dc64b5743252dbaef6e30521c34d6bbd1620c8ce65bdb7bf9e7143b61bb5b183/hosts /etc/hosts rw,relatime - ext4 /dev/vda1 rw",
+			expectedContainerID: "dc64b5743252dbaef6e30521c34d6bbd1620c8ce65bdb7bf9e7143b61bb5b183",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			containerID := getContainerIDFromCgroupV2Line(tc.line)
+			assert.Equal(t, tc.expectedContainerID, containerID)
+		})
+	}
+}