Add TestZombies and improve exec output handling

cmd/runmqserver/main.go

@@ -19,6 +19,7 @@ package main
 
 import (
 	"errors"
+	"fmt"
 	"io/ioutil"
 	"log"
 	"os"
@@ -30,6 +31,20 @@ import (
 	"github.com/ibm-messaging/mq-container/internal/name"
 )
 
+var debug = false
+
+func logDebug(msg string) {
+	if debug {
+		log.Printf("DEBUG: %v", msg)
+	}
+}
+
+func logDebugf(format string, args ...interface{}) {
+	if debug {
+		log.Printf("DEBUG: %v", fmt.Sprintf(format, args...))
+	}
+}
+
 // createDirStructure creates the default MQ directory structure under /var/mqm
 func createDirStructure() error {
 	out, _, err := command.Run("/opt/mqm/bin/crtmqdir", "-f", "-s")
@@ -127,6 +142,10 @@ func stopQueueManager(name string) error {
 }
 
 func doMain() error {
+	debugEnv, ok := os.LookupEnv("DEBUG")
+	if ok && (debugEnv == "true" || debugEnv == "1") {
+		debug = true
+	}
 	accepted, err := checkLicense()
 	if err != nil {
 		return err

cmd/runmqserver/signals.go

@@ -50,11 +50,13 @@ func signalHandler(qmgr string) chan int {
 				// End the goroutine
 				return
 			case <-reapSignals:
+				logDebug("Received SIGCHLD signal")
 				reapZombies()
 			case job := <-control:
 				switch {
 				case job == startReaping:
 					// Add SIGCHLD to the list of signals we're listening to
+					logDebug("Listening for SIGCHLD signals")
 					signal.Notify(reapSignals, syscall.SIGCHLD)
 				case job == reapNow:
 					reapZombies()
@@ -75,5 +77,6 @@ func reapZombies() {
 		if pid == 0 || err == unix.ECHILD {
 			return
 		}
+		logDebugf("Reaped PID %v", pid)
 	}
 }