101 lines
2.6 KiB
Go
101 lines
2.6 KiB
Go
// 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/v1.21.0"
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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()
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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.ContainerID(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 {
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return ""
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}
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return matches[1]
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}
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