container.go

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//
//     http://www.apache.org/licenses/LICENSE-2.0
//
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package linux

import (
	"bufio"
	"bytes"
	"fmt"
	"os"
)

const procOneCgroup = "/proc/1/cgroup"

// IsContainerized returns true if this process is containerized.
func IsContainerized() (bool, error) {
	data, err := os.ReadFile(procOneCgroup)
	if err != nil {
		if os.IsNotExist(err) {
			return false, nil
		}

		return false, fmt.Errorf("failed to read process cgroups: %w", err)
	}

	return isContainerizedCgroup(data)
}

func isContainerizedCgroup(data []byte) (bool, error) {
	s := bufio.NewScanner(bytes.NewReader(data))
	for n := 0; s.Scan(); n++ {
		line := s.Bytes()

		// Following a suggestion on Stack Overflow on how to detect
		// being inside a container: https://stackoverflow.com/a/20012536/235203
		if bytes.Contains(line, []byte("docker")) || bytes.Contains(line, []byte(".slice")) || bytes.Contains(line, []byte("lxc")) || bytes.Contains(line, []byte("kubepods")) {
			return true, nil
		}
	}

	return false, s.Err()
}