add multi-instance Queue Managers (#307)

* Initial code to implement multi-instance queue manager

* alter default mqsc to prevent race between listeners on standby startup

* Updates to multi-instance queue manager code

* initial multi instance test

* Multi-instance code improvements

* Multi instance fixes and first test

* configure queue manager

* Add mirror log filtering for mult-instance QMs

* Add log message for multi-instance enabled

* Improvements to container runtime logging

* refactor test

* Test active standby switch

* Improve createQueueManager function

* Test multi instance race

* wait

* multi instance mount tests

* skip race test

* mount tests

* no mount test

* single instance split mount tests

* readiness check

* More updates for handling standby queue manager

* Improve standby checks

* Minor fixes to miqm

* Fix logging of JSON errors

* Update copyrights

* Fix log includes

internal/metrics/metrics.go

@@ -1,5 +1,5 @@
 /*
-© Copyright IBM Corporation 2018
+© Copyright IBM Corporation 2018, 2019
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -24,6 +24,7 @@ import (
 	"time"
 
 	"github.com/ibm-messaging/mq-container/internal/logger"
+	"github.com/ibm-messaging/mq-container/internal/ready"
 	"github.com/prometheus/client_golang/prometheus"
 )
 
@@ -39,6 +40,15 @@ var (
 // GatherMetrics gathers metrics for the queue manager
 func GatherMetrics(qmName string, log *logger.Logger) {
 
+	// If running in standby mode - wait until the queue manager becomes active
+	for {
+		active, _ := ready.IsRunningAsActiveQM(qmName)
+		if active {
+			break
+		}
+		time.Sleep(requestTimeout * time.Second)
+	}
+
 	metricsEnabled = true
 
 	err := startMetricsGathering(qmName, log)