14807: Send detached crunch-run logs to journal via systemd-cat.

Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tclegg@veritasgenetics.com>

diff --git a/services/crunch-run/background.go b/services/crunch-run/background.go
index 334b3ab674ee9534eb7e30c4bcd2fb700e93cc2a..b3c530e69013e91dfb7599c677347ecef3856d78 100644 (file)
--- a/services/crunch-run/background.go
+++ b/services/crunch-run/background.go
@@ -8,7 +8,6 @@ import (
        "encoding/json"
        "fmt"
        "io"
-       "io/ioutil"
        "os"
        "os/exec"
        "path/filepath"
@@ -25,16 +24,17 @@ var (
 
 // procinfo is saved in each process's lockfile.
 type procinfo struct {
-       UUID   string
-       PID    int
-       Stdout string
-       Stderr string
+       UUID string
+       PID  int
 }
 
 // Detach acquires a lock for the given uuid, and starts the current
 // program as a child process (with -no-detach prepended to the given
 // arguments so the child knows not to detach again). The lock is
 // passed along to the child process.
+//
+// Stdout and stderr in the child process are sent to the systemd
+// journal using the systemd-cat program.
 func Detach(uuid string, args []string, stdout, stderr io.Writer) int {
        return exitcode(stderr, detach(uuid, args, stdout, stderr))
 }
@@ -67,21 +67,7 @@ func detach(uuid string, args []string, stdout, stderr io.Writer) error {
        defer lockfile.Close()
        lockfile.Truncate(0)
 
-       outfile, err := ioutil.TempFile("", "crunch-run-"+uuid+"-stdout-")
-       if err != nil {
-               return err
-       }
-       defer outfile.Close()
-       errfile, err := ioutil.TempFile("", "crunch-run-"+uuid+"-stderr-")
-       if err != nil {
-               os.Remove(outfile.Name())
-               return err
-       }
-       defer errfile.Close()
-
-       cmd := exec.Command(args[0], append([]string{"-no-detach"}, args[1:]...)...)
-       cmd.Stdout = outfile
-       cmd.Stderr = errfile
+       cmd := exec.Command("systemd-cat", append([]string{"--identifier=crunch-run", args[0], "-no-detach"}, args[1:]...)...)
        // Child inherits lockfile.
        cmd.ExtraFiles = []*os.File{lockfile}
        // Ensure child isn't interrupted even if we receive signals
@@ -90,24 +76,14 @@ func detach(uuid string, args []string, stdout, stderr io.Writer) error {
        cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
        err = cmd.Start()
        if err != nil {
-               os.Remove(outfile.Name())
-               os.Remove(errfile.Name())
                return fmt.Errorf("exec %s: %s", cmd.Path, err)
        }
 
        w := io.MultiWriter(stdout, lockfile)
-       err = json.NewEncoder(w).Encode(procinfo{
-               UUID:   uuid,
-               PID:    cmd.Process.Pid,
-               Stdout: outfile.Name(),
-               Stderr: errfile.Name(),
+       return json.NewEncoder(w).Encode(procinfo{
+               UUID: uuid,
+               PID:  cmd.Process.Pid,
        })
-       if err != nil {
-               os.Remove(outfile.Name())
-               os.Remove(errfile.Name())
-               return err
-       }
-       return nil
 }
 
 // KillProcess finds the crunch-run process corresponding to the given