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Add container id support to Resource (#2418)
* Add container id support to Resource * Fix wrong test case name * Add WithContainer option * Update CHANGELOG * Fix comments * Update CHANGELOG * Use regex to find container id * Add tests for reading cgroup file * Update sdk/resource/container.go Co-authored-by: Chester Cheung <[email protected]> * Update format Co-authored-by: Chester Cheung <[email protected]> Co-authored-by: Anthony Mirabella <[email protected]>
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‎CHANGELOG.md‎

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@@ -26,6 +26,7 @@ This update is a breaking change of the unstable Metrics API. Code instrumented
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If the provided environment variables are invalid (negative), the default values would be used.
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- Rename the `gc` runtime name to `go` (#2560)
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- Add container id support to Resource. (#2418)
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- Add span attribute value length limit.
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The new `AttributeValueLengthLimit` field is added to the `"go.opentelemetry.io/otel/sdk/trace".SpanLimits` type to configure this limit for a `TracerProvider`.
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The default limit for this resource is "unlimited". (#2637)

‎sdk/resource/config.go‎

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@@ -171,3 +171,16 @@ func WithProcessRuntimeVersion() Option {
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func WithProcessRuntimeDescription() Option {
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return WithDetectors(processRuntimeDescriptionDetector{})
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}
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// WithContainer adds all the Container attributes to the configured Resource.
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// See individual WithContainer* functions to configure specific attributes.
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func WithContainer() Option {
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return WithDetectors(
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cgroupContainerIDDetector{},
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)
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}
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// WithContainerID adds an attribute with the id of the container to the configured Resource.
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func WithContainerID() Option {
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return WithDetectors(cgroupContainerIDDetector{})
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}

‎sdk/resource/container.go‎

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@@ -0,0 +1,100 @@
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// Copyright The OpenTelemetry Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package resource // import "go.opentelemetry.io/otel/sdk/resource"
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import (
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"bufio"
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"context"
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"errors"
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"io"
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"os"
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"regexp"
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semconv "go.opentelemetry.io/otel/semconv/v1.7.0"
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)
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type containerIDProvider func() (string, error)
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var (
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containerID containerIDProvider = getContainerIDFromCGroup
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cgroupContainerIDRe = regexp.MustCompile(`^.*/(?:.*-)?([0-9a-f]+)(?:\.|\s*$)`)
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)
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type cgroupContainerIDDetector struct{}
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const cgroupPath = "/proc/self/cgroup"
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// Detect returns a *Resource that describes the id of the container.
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// If no container id found, an empty resource will be returned.
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func (cgroupContainerIDDetector) Detect(ctx context.Context) (*Resource, error) {
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containerID, err := containerID()
43+
if err != nil {
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return nil, err
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}
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if containerID == "" {
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return Empty(), nil
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}
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return NewWithAttributes(semconv.SchemaURL, semconv.ContainerIDKey.String(containerID)), nil
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}
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var (
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defaultOSStat = os.Stat
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osStat = defaultOSStat
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defaultOSOpen = func(name string) (io.ReadCloser, error) {
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return os.Open(name)
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}
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osOpen = defaultOSOpen
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)
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// getContainerIDFromCGroup returns the id of the container from the cgroup file.
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// If no container id found, an empty string will be returned.
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func getContainerIDFromCGroup() (string, error) {
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if _, err := osStat(cgroupPath); errors.Is(err, os.ErrNotExist) {
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// File does not exist, skip
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return "", nil
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}
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file, err := osOpen(cgroupPath)
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if err != nil {
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return "", err
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}
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defer file.Close()
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return getContainerIDFromReader(file), nil
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}
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// getContainerIDFromReader returns the id of the container from reader.
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func getContainerIDFromReader(reader io.Reader) string {
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scanner := bufio.NewScanner(reader)
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for scanner.Scan() {
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line := scanner.Text()
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if id := getContainerIDFromLine(line); id != "" {
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return id
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}
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}
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return ""
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}
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// getContainerIDFromLine returns the id of the container from one string line.
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func getContainerIDFromLine(line string) string {
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matches := cgroupContainerIDRe.FindStringSubmatch(line)
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if len(matches) <= 1 {
97+
return ""
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}
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return matches[1]
100+
}

‎sdk/resource/container_test.go‎

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@@ -0,0 +1,169 @@
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// Copyright The OpenTelemetry Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12+
// See the License for the specific language governing permissions and
13+
// limitations under the License.
14+
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package resource
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import (
18+
"errors"
19+
"io"
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"os"
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"strings"
22+
"testing"
23+
24+
"github.com/stretchr/testify/assert"
25+
)
26+
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func setDefaultContainerProviders() {
28+
setContainerProviders(
29+
getContainerIDFromCGroup,
30+
)
31+
}
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33+
func setContainerProviders(
34+
idProvider containerIDProvider,
35+
) {
36+
containerID = idProvider
37+
}
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func TestGetContainerIDFromLine(t *testing.T) {
40+
testCases := []struct {
41+
name string
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line string
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expectedContainerID string
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}{
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{
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name: "with suffix",
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line: "13:name=systemd:/podruntime/docker/kubepods/ac679f8a8319c8cf7d38e1adf263bc08d23.aaaa",
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expectedContainerID: "ac679f8a8319c8cf7d38e1adf263bc08d23",
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},
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{
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name: "with prefix and suffix",
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line: "13:name=systemd:/podruntime/docker/kubepods/crio-dc679f8a8319c8cf7d38e1adf263bc08d23.stuff",
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expectedContainerID: "dc679f8a8319c8cf7d38e1adf263bc08d23",
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},
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{
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name: "no prefix and suffix",
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line: "13:name=systemd:/pod/d86d75589bf6cc254f3e2cc29debdf85dde404998aa128997a819ff991827356",
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expectedContainerID: "d86d75589bf6cc254f3e2cc29debdf85dde404998aa128997a819ff991827356",
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},
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{
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name: "with space",
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line: " 13:name=systemd:/pod/d86d75589bf6cc254f3e2cc29debdf85dde404998aa128997a819ff991827356 ",
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expectedContainerID: "d86d75589bf6cc254f3e2cc29debdf85dde404998aa128997a819ff991827356",
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},
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{
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name: "invalid hex string",
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line: "13:name=systemd:/podruntime/docker/kubepods/ac679f8a8319c8cf7d38e1adf263bc08d23zzzz",
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},
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{
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name: "no container id - 1",
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line: "pids: /",
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},
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{
74+
name: "no container id - 2",
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line: "pids: ",
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},
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}
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for _, tc := range testCases {
80+
t.Run(tc.name, func(t *testing.T) {
81+
containerID := getContainerIDFromLine(tc.line)
82+
assert.Equal(t, tc.expectedContainerID, containerID)
83+
})
84+
}
85+
}
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87+
func TestGetContainerIDFromReader(t *testing.T) {
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testCases := []struct {
89+
name string
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reader io.Reader
91+
expectedContainerID string
92+
}{
93+
{
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name: "multiple lines",
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reader: strings.NewReader(`//
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1:name=systemd:/podruntime/docker/kubepods/docker-dc579f8a8319c8cf7d38e1adf263bc08d23
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1:name=systemd:/podruntime/docker/kubepods/docker-dc579f8a8319c8cf7d38e1adf263bc08d24
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`),
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expectedContainerID: "dc579f8a8319c8cf7d38e1adf263bc08d23",
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},
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{
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name: "no container id",
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reader: strings.NewReader(`//
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1:name=systemd:/podruntime/docker
105+
`),
106+
expectedContainerID: "",
107+
},
108+
}
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for _, tc := range testCases {
111+
t.Run(tc.name, func(t *testing.T) {
112+
containerID := getContainerIDFromReader(tc.reader)
113+
assert.Equal(t, tc.expectedContainerID, containerID)
114+
})
115+
}
116+
}
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118+
func TestGetContainerIDFromCGroup(t *testing.T) {
119+
t.Cleanup(func() {
120+
osStat = defaultOSStat
121+
osOpen = defaultOSOpen
122+
})
123+
124+
testCases := []struct {
125+
name string
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cgroupFileNotExist bool
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openFileError error
128+
content string
129+
expectedContainerID string
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expectedError bool
131+
}{
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{
133+
name: "the cgroup file does not exist",
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cgroupFileNotExist: true,
135+
},
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{
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name: "error when opening cgroup file",
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openFileError: errors.New("test"),
139+
expectedError: true,
140+
},
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{
142+
name: "cgroup file",
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content: "1:name=systemd:/podruntime/docker/kubepods/docker-dc579f8a8319c8cf7d38e1adf263bc08d23",
144+
expectedContainerID: "dc579f8a8319c8cf7d38e1adf263bc08d23",
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},
146+
}
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for _, tc := range testCases {
149+
t.Run(tc.name, func(t *testing.T) {
150+
osStat = func(name string) (os.FileInfo, error) {
151+
if tc.cgroupFileNotExist {
152+
return nil, os.ErrNotExist
153+
}
154+
return nil, nil
155+
}
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157+
osOpen = func(name string) (io.ReadCloser, error) {
158+
if tc.openFileError != nil {
159+
return nil, tc.openFileError
160+
}
161+
return io.NopCloser(strings.NewReader(tc.content)), nil
162+
}
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164+
containerID, err := getContainerIDFromCGroup()
165+
assert.Equal(t, tc.expectedError, err != nil)
166+
assert.Equal(t, tc.expectedContainerID, containerID)
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})
168+
}
169+
}

‎sdk/resource/export_test.go‎

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@@ -23,6 +23,8 @@ var (
2323
SetUserProviders = setUserProviders
2424
SetDefaultOSDescriptionProvider = setDefaultOSDescriptionProvider
2525
SetOSDescriptionProvider = setOSDescriptionProvider
26+
SetDefaultContainerProviders = setDefaultContainerProviders
27+
SetContainerProviders = setContainerProviders
2628
)
2729

2830
var (

‎sdk/resource/process_test.go‎

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Original file line numberDiff line numberDiff line change
@@ -102,13 +102,14 @@ func restoreAttributesProviders() {
102102
resource.SetDefaultRuntimeProviders()
103103
resource.SetDefaultUserProviders()
104104
resource.SetDefaultOSDescriptionProvider()
105+
resource.SetDefaultContainerProviders()
105106
}
106107

107108
func TestWithProcessFuncsErrors(t *testing.T) {
108109
mockProcessAttributesProvidersWithErrors()
109110

110-
t.Run("WithPID", testWithProcessExecutablePathError)
111-
t.Run("WithExecutableName", testWithProcessOwnerError)
111+
t.Run("WithExecutablePath", testWithProcessExecutablePathError)
112+
t.Run("WithOwner", testWithProcessOwnerError)
112113

113114
restoreAttributesProviders()
114115
}

‎sdk/resource/resource_test.go‎

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@@ -649,3 +649,74 @@ func hostname() string {
649649
}
650650
return hn
651651
}
652+
653+
func TestWithContainerID(t *testing.T) {
654+
t.Cleanup(restoreAttributesProviders)
655+
656+
fakeContainerID := "fake-container-id"
657+
658+
testCases := []struct {
659+
name string
660+
containerIDProvider func() (string, error)
661+
expectedResource map[string]string
662+
expectedErr bool
663+
}{
664+
{
665+
name: "get container id",
666+
containerIDProvider: func() (string, error) {
667+
return fakeContainerID, nil
668+
},
669+
expectedResource: map[string]string{
670+
string(semconv.ContainerIDKey): fakeContainerID,
671+
},
672+
},
673+
{
674+
name: "no container id found",
675+
containerIDProvider: func() (string, error) {
676+
return "", nil
677+
},
678+
expectedResource: map[string]string{},
679+
},
680+
{
681+
name: "error",
682+
containerIDProvider: func() (string, error) {
683+
return "", fmt.Errorf("unable to get container id")
684+
},
685+
expectedResource: map[string]string{},
686+
expectedErr: true,
687+
},
688+
}
689+
690+
for _, tc := range testCases {
691+
t.Run(tc.name, func(t *testing.T) {
692+
resource.SetContainerProviders(tc.containerIDProvider)
693+
694+
res, err := resource.New(context.Background(),
695+
resource.WithContainerID(),
696+
)
697+
698+
if tc.expectedErr {
699+
assert.Error(t, err)
700+
}
701+
assert.Equal(t, tc.expectedResource, toMap(res))
702+
})
703+
}
704+
}
705+
706+
func TestWithContainer(t *testing.T) {
707+
t.Cleanup(restoreAttributesProviders)
708+
709+
fakeContainerID := "fake-container-id"
710+
resource.SetContainerProviders(func() (string, error) {
711+
return fakeContainerID, nil
712+
})
713+
714+
res, err := resource.New(context.Background(),
715+
resource.WithContainer(),
716+
)
717+
718+
assert.NoError(t, err)
719+
assert.Equal(t, map[string]string{
720+
string(semconv.ContainerIDKey): fakeContainerID,
721+
}, toMap(res))
722+
}

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