Fix #4

Fixes an issue where a job had a date of the year 0001, meaning
the values were negative when added up. This was from jobs
which were queued or still running.

Thanks to folks on the issue for their input

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Author: alexellis

main.go

@@ -181,10 +181,14 @@ func main() {
 			log.Printf("%d jobs for workflow run: %d", len(workflowJobs), run.GetID())
 			for _, job := range workflowJobs {
 
-				dur := job.GetCompletedAt().Time.Sub(job.GetStartedAt().Time)
-				allUsage += dur
-				log.Printf("Job: %d [%s - %s] (%s): %s",
-					job.GetID(), job.GetStartedAt().Format("2006-01-02 15:04:05"), job.GetCompletedAt().Format("2006-01-02 15:04:05"), humanDuration(dur), job.GetConclusion())
+				if !job.GetCompletedAt().IsZero() {
+					dur := job.GetCompletedAt().Time.Sub(job.GetStartedAt().Time)
+					allUsage += dur
+					log.Printf("Job: %d [%s - %s] (%s): %s",
+						job.GetID(), job.GetStartedAt().Format("2006-01-02 15:04:05"),
+						job.GetCompletedAt().Format("2006-01-02 15:04:05"),
+						humanDuration(dur), job.GetConclusion())
+				}
 			}
 		}
 	}