lntest: add flag -goroutinedump

lntest/harness.go

@@ -652,6 +652,11 @@ func (n *NetworkHarness) StopNode(node *HarnessNode) error {
 // SaveProfilesPages hits profiles pages of all active nodes and writes it to
 // disk using a similar naming scheme as to the regular set of logs.
 func (n *NetworkHarness) SaveProfilesPages() {
+	// Only write gorutine dumps if flag is active.
+	if !(*goroutineDump) {
+		return
+	}
+
 	for _, node := range n.activeNodes {
 		if err := saveProfilesPage(node); err != nil {
 			fmt.Println(err)

lntest/node.go

@@ -80,7 +80,12 @@ var (
 	// logOutput is a flag that can be set to append the output from the
 	// seed nodes to log files.
 	logOutput = flag.Bool("logoutput", false,
-		"log output from node n to file outputn.log")
+		"log output from node n to file output-n.log")
+
+	// goroutineDump is a flag that can be set to dump the active
+	// goroutines of test nodes on failure.
+	goroutineDump = flag.Bool("goroutinedump", false,
+		"write goroutine dump from node n to file pprof-n.log")
 )
 
 // generateListeningPorts returns three ints representing ports to listen on