10585: Clean up defaults and error checks; release ticker when finished.

diff --git a/services/crunchstat/crunchstat.go b/services/crunchstat/crunchstat.go
index 510df3bac676afbc56589e5343b0a20e002baea7..e71989afb82cc6df750d6a3627247f418c0e5db5 100644 (file)
--- a/services/crunchstat/crunchstat.go
+++ b/services/crunchstat/crunchstat.go
@@ -16,8 +16,10 @@ import (
 
 const MaxLogLine = 1 << 14 // Child stderr lines >16KiB will be split
 
-var signalOnDeadPPID int
-var ppidCheckInterval = time.Second
+var (
+       signalOnDeadPPID  int = 15
+       ppidCheckInterval     = time.Second
+)
 
 func main() {
        reporter := crunchstat.Reporter{
@@ -27,7 +29,7 @@ func main() {
        flag.StringVar(&reporter.CgroupRoot, "cgroup-root", "", "Root of cgroup tree")
        flag.StringVar(&reporter.CgroupParent, "cgroup-parent", "", "Name of container parent under cgroup")
        flag.StringVar(&reporter.CIDFile, "cgroup-cid", "", "Path to container id file")
-       flag.IntVar(&signalOnDeadPPID, "signal-on-dead-ppid", 15, "Signal to send child if crunchstat's parent process disappears")
+       flag.IntVar(&signalOnDeadPPID, "signal-on-dead-ppid", signalOnDeadPPID, "Signal to send child if crunchstat's parent process disappears (0 to disable)")
        flag.DurationVar(&ppidCheckInterval, "ppid-check-interval", ppidCheckInterval, "Time between checks for parent process disappearance")
        pollMsec := flag.Int64("poll", 1000, "Reporting interval, in milliseconds")
 
@@ -35,6 +37,8 @@ func main() {
 
        if reporter.CgroupRoot == "" {
                reporter.Logger.Fatal("error: must provide -cgroup-root")
+       } else if signalOnDeadPPID < 0 {
+               reporter.Logger.Fatalf("-signal-on-dead-ppid=%d is invalid (use a positive signal number, or 0 to disable)", signalOnDeadPPID)
        }
        reporter.PollPeriod = time.Duration(*pollMsec) * time.Millisecond
 
@@ -84,7 +88,7 @@ func runCommand(argv []string, logger *log.Logger) error {
 
        // Kill our child proc if our parent process disappears
        if signalOnDeadPPID != 0 {
-               go sendSignalOnDeadPPID(signalOnDeadPPID, os.Getppid(), cmd, logger)
+               go sendSignalOnDeadPPID(ppidCheckInterval, signalOnDeadPPID, os.Getppid(), cmd, logger)
        }
 
        // Funnel stderr through our channel
@@ -107,8 +111,9 @@ func runCommand(argv []string, logger *log.Logger) error {
        return cmd.Wait()
 }
 
-func sendSignalOnDeadPPID(signum, ppidOrig int, cmd *exec.Cmd, logger *log.Logger) {
-       for _ = range time.NewTicker(ppidCheckInterval).C {
+func sendSignalOnDeadPPID(intvl time.Duration, signum, ppidOrig int, cmd *exec.Cmd, logger *log.Logger) {
+       ticker := time.NewTicker(intvl)
+       for _ = range ticker.C {
                ppid := os.Getppid()
                if ppid == ppidOrig {
                        continue
@@ -120,9 +125,10 @@ func sendSignalOnDeadPPID(signum, ppidOrig int, cmd *exec.Cmd, logger *log.Logge
                logger.Printf("notice: crunchstat ppid changed from %d to %d -- killing child pid %d with signal %d", ppidOrig, ppid, cmd.Process.Pid, signum)
                err := cmd.Process.Signal(syscall.Signal(signum))
                if err != nil {
-                       logger.Printf("error: sending signal: %d", err)
+                       logger.Printf("error: sending signal: %s", err)
                        continue
                }
+               ticker.Stop()
                break
        }
 }