Add basic status checking for batch job types.

Nomad job type batch does not support the deployment model which
meant previously Levant would just exit after the job was
registered. This update adds additional functionality which means
Levant will at least confirm the job has a status of running
before exiting.

Closes #53

levant/deploy.go

@@ -84,9 +84,8 @@ func (c *nomadClient) Deploy(job *nomad.Job, autoPromote int, forceCount bool) (
 	}
 
 	// GH-50: batch job types do not return an evaluation upon registration.
-	if eval == nil && *job.Type == nomadStructs.JobTypeBatch {
-		logging.Debug("levant/deploy: job type %s does not create evaluations", nomadStructs.JobTypeBatch)
-		return true
+	if eval.EvalID == "" && *job.Type == nomadStructs.JobTypeBatch {
+		return c.checkBatchJob(job.Name)
 	}
 
 	// Trigger the evaluationInspector to identify any potential errors in the

levant/job_status_checker.go

@@ -0,0 +1,53 @@
+package levant
+
+import (
+	"time"
+
+	nomad "github.com/hashicorp/nomad/api"
+	nomadStructs "github.com/hashicorp/nomad/nomad/structs"
+	"github.com/jrasell/levant/logging"
+)
+
+// checkBatchJob checks the status of a batch job at least reaches a status of
+// running. This is required as currently Nomad does not support deployments of
+// job type batch.
+func (c *nomadClient) checkBatchJob(jobName *string) bool {
+
+	// Initialiaze our WaitIndex
+	var wi uint64
+
+	// Setup the Nomad QueryOptions to allow blocking query and a timeout.
+	q := &nomad.QueryOptions{WaitIndex: wi}
+	timeout := time.Tick(time.Minute * 5)
+
+	for {
+
+		job, meta, err := c.nomad.Jobs().Info(*jobName, q)
+		if err != nil {
+			logging.Error("levant/job_status_checker: unable to query batch job %s: %v", *jobName, err)
+			return false
+		}
+
+		// If the LastIndex is not greater than our stored LastChangeIndex, we don't
+		// need to do anything.
+		if meta.LastIndex <= wi {
+			continue
+		}
+
+		if *job.Status == nomadStructs.JobStatusRunning {
+			logging.Info("levant/job_status_checker: batch job %s has status %s", *jobName, *job.Status)
+			return true
+		}
+
+		select {
+		case <-timeout:
+			logging.Error("levant/job_status_checker: timeout reached while verifying the status of batch job %s",
+				*jobName)
+			return false
+		default:
+			logging.Debug("levant/job_status_checker: batch job %s currently has status %s", *jobName, *job.Status)
+			q.WaitIndex = meta.LastIndex
+			continue
+		}
+	}
+}