tremplin: log LXD's stdout and stderr
LXD usually logs to syslog, but during a panic it only writes
to stderr. Catch the stderr (and stdout for good measure) to
help debugging.
BUG=b:231408845
TEST=cros_workon_make --install --test --board=tatl chromeos-base/tremplin && chromite/contrib/guestos/deploy_to_termina --board tatl dut chromeos-base/tremplin --restart-services
Change-Id: I88e8a3e3a0ddbf6a13fdd2776bbaad8b094c8004
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/tremplin/+/3629843
Reviewed-by: Nicholas Verne <nverne@chromium.org>
Commit-Queue: David Munro <davidmunro@google.com>
Reviewed-by: David Munro <davidmunro@google.com>
Tested-by: David Munro <davidmunro@google.com>
diff --git a/src/chromiumos/tremplin/lxd_helper.go b/src/chromiumos/tremplin/lxd_helper.go
index eafe1ec..fbf88cb 100644
--- a/src/chromiumos/tremplin/lxd_helper.go
+++ b/src/chromiumos/tremplin/lxd_helper.go
@@ -7,6 +7,7 @@
import (
"context"
"fmt"
+ "io"
"log"
"os"
"os/exec"
@@ -116,16 +117,57 @@
}
}
+func readIntoLog(c chan int, name string, r io.Reader) {
+ defer close(c)
+ buf := make([]byte, 1024)
+ for {
+ n, err := r.Read(buf)
+ if err == io.EOF {
+ return
+ }
+ if err != nil {
+ log.Print(name, " ERROR: ", err)
+ return
+ }
+ if n < 1 {
+ continue
+ }
+ lines := strings.Split(string(buf[:n]), "\n")
+ nl := len(lines)
+ if nl > 1 && lines[nl-1] == "" {
+ lines = lines[:nl-1]
+ }
+ for _, line := range lines {
+ log.Print("lxd ", name, ": ", line)
+ }
+ }
+}
+
// runLxd launches LXD and blocks until LXD exits. Will set l.process.
func (l *lxdHelper) runLxd() error {
log.Printf("Running %q", strings.Join(lxdCmd, " "))
cmd := exec.Command(lxdCmd[0], lxdCmd[1:]...)
- err := cmd.Start()
- if err == nil {
- log.Print("LXD started")
- l.process = cmd.Process
- return cmd.Wait()
+ stdout, err := cmd.StdoutPipe()
+ if err != nil {
+ return err
}
+ stderr, err := cmd.StderrPipe()
+ if err != nil {
+ return err
+ }
+ wc_stdout := make(chan int)
+ go readIntoLog(wc_stdout, "stdout", stdout)
+ wc_stderr := make(chan int)
+ go readIntoLog(wc_stderr, "stderr", stderr)
+ err = cmd.Start()
+ if err != nil {
+ return err
+ }
+ log.Print("LXD started")
+ l.process = cmd.Process
+ err = cmd.Wait()
+ <-wc_stdout
+ <-wc_stderr
return err
}
