Update readiness check

internal/ready/ready.go

@@ -0,0 +1,70 @@
+/*
+© Copyright IBM Corporation 2018
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package ready contains code to provide a ready signal mechanism between processes
+package ready
+
+import (
+	"io/ioutil"
+	"os"
+
+	log "github.com/sirupsen/logrus"
+)
+
+const fileName string = "/tmp/runmqserverReady"
+
+func fileExists() (bool, error) {
+	_, err := os.Stat(fileName)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return false, err
+		}
+		return false, nil
+	}
+	return true, nil
+}
+
+// Clear ensures that any readiness state is cleared
+func Clear() error {
+	log.Debug("Clear()")
+	exist, err := fileExists()
+	if err != nil {
+		return err
+	}
+	if exist {
+		return os.Remove(fileName)
+	}
+	return nil
+}
+
+// Set lets any subsequent calls to `CheckReady` know that the queue
+// manager has finished its configuration step
+func Set() error {
+	log.Debug("Set()")
+	return ioutil.WriteFile(fileName, []byte("1"), 0770)
+}
+
+// Check checks whether or not the queue manager has finished its
+// configuration steps
+func Check() (bool, error) {
+	exists, err := fileExists()
+	if err != nil {
+		log.Debug("Check() -> false")
+		return false, err
+	}
+	log.Debugf("Check() -> %v", exists)
+	return exists, nil
+}