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0511fdb431
Adds a logging daemon that collects logs in a ring buffer in a runc container. The tools logwrite and logread can be used to read/write logs. The logging daemon can be sent open file descriptors that will be read and included in the logs. Modifies init to start the daemon and use logwrite to capture logs from runc. Signed-off-by: Magnus Skjegstad <magnus@skjegstad.com>
77 lines
2.0 KiB
Go
77 lines
2.0 KiB
Go
package main
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import (
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"flag"
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"fmt"
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"log"
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"net"
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"os"
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"os/exec"
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"syscall"
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)
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func main() {
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var socketLogPath string
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var socketQueryPath string
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var memlogdBundle string
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var pidFile string
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var detach bool
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flag.StringVar(&socketLogPath, "socket-log", "/tmp/memlogd.sock", "path to fd logging socket. Created and passed to logging container. Existing socket will be removed.")
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flag.StringVar(&socketQueryPath, "socket-query", "/tmp/memlogdq.sock", "path to query socket. Created and passed to logging container. Existing socket will be removed.")
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flag.StringVar(&memlogdBundle, "bundle", "/containers/init/memlogd", "runc bundle with memlogd")
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flag.StringVar(&pidFile, "pid-file", "/run/memlogd.pid", "path to pid file")
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flag.BoolVar(&detach, "detach", true, "detach from subprocess")
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flag.Parse()
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laddr := net.UnixAddr{socketLogPath, "unixgram"}
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os.Remove(laddr.Name) // remove existing socket
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lconn, err := net.ListenUnixgram("unixgram", &laddr)
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if err != nil {
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panic(err)
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}
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lfd, err := lconn.File()
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if err != nil {
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panic(err)
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}
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qaddr := net.UnixAddr{socketQueryPath, "unix"}
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os.Remove(qaddr.Name) // remove existing socket
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qconn, err := net.ListenUnix("unix", &qaddr)
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if err != nil {
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panic(err)
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}
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qfd, err := qconn.File()
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if err != nil {
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panic(err)
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}
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cmd := exec.Command("/sbin/start-stop-daemon", "--start", "--pidfile", pidFile,
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"--exec", "/usr/bin/runc", "--", "run", "--preserve-fds=2",
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"--bundle", memlogdBundle,
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"--pid-file", pidFile, "memlogd")
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log.Println(cmd.Args)
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cmd.ExtraFiles = append(cmd.ExtraFiles, lfd, qfd)
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cmd.Stdout = os.Stdout
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cmd.Stderr = os.Stderr
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if err := cmd.Start(); err != nil {
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panic(err)
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}
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if detach {
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if err := cmd.Process.Release(); err != nil {
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panic(err)
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}
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} else {
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if err := cmd.Wait(); err != nil {
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if exitError, ok := err.(*exec.ExitError); ok {
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// exit with exit code from process
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status := exitError.Sys().(syscall.WaitStatus)
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os.Exit(status.ExitStatus())
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} else {
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// no exit code, report error and exit 1
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fmt.Println(err)
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os.Exit(1)
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}
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}
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}
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}
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