Add wait function

Peter Jönsson · Peter Jönsson · commit 206676149166 · 2014-01-10T22:28:35.000+01:00
diff --git a/wait.go b/wait.go
@@ -0,0 +1,56 @@
+package gopherstack
+
+import (
+	"fmt"
+	"log"
+	"time"
+)
+
+// waitForAsyncJob simply blocks until the the asynchronous job has
+// executed or has timed out.
+func WaitForAsyncJob(jobId string, client *CloudStackClient, timeout time.Duration) error {
+	done := make(chan struct{})
+	defer close(done)
+
+	result := make(chan error, 1)
+	go func() {
+		attempts := 0
+		for {
+			attempts += 1
+
+			log.Printf("Checking async job status... (attempt: %d)", attempts)
+			status, err := client.QueryAsyncJobResult(jobId)
+			if err != nil {
+				result <- err
+				return
+			}
+
+			// check what the real state will be.
+			if status == 1 {
+				result <- nil
+				return
+			}
+
+			// Wait 3 seconds in between
+			time.Sleep(3 * time.Second)
+
+			// Verify we shouldn't exit
+			select {
+			case <-done:
+				// We finished, so just exit the goroutine
+				return
+			default:
+				// Keep going
+			}
+		}
+	}()
+
+	log.Printf("Waiting for up to %d seconds for async job %s", timeout, jobId)
+	select {
+	case err := <-result:
+		return err
+	case <-time.After(timeout):
+		err := fmt.Errorf("Timeout while waiting to for async job to finish")
+		return err
+	}
+}
