Fix environment recovery

As the environment is no longer stored in the meta information,
Poseidon wasn't able to recover environments. It expected the
environment id to be found in the meta data. We now recover
the environment id from the job id.

environment/manager.go

@@ -100,11 +100,15 @@ func (m *NomadEnvironmentManager) Load() error {
 			jobLogger.Infof("Couldn't convert pool size to int: %v, skipping ...", err)
 			continue
 		}
-		environmentID, err := runner.NewEnvironmentID(configTaskGroup.Meta[nomad.ConfigMetaEnvironmentKey])
+		environmentIDString, err := runner.EnvironmentIDFromTemplateJobID(*job.ID)
 		if err != nil {
-			jobLogger.WithField("environmentID", configTaskGroup.Meta[nomad.ConfigMetaEnvironmentKey]).
+			jobLogger.WithError(err).Error("Couldn't retrieve environment id from template job")
+		}
+		environmentID, err := runner.NewEnvironmentID(environmentIDString)
+		if err != nil {
+			jobLogger.WithField("environmentID", environmentIDString).
 				WithError(err).
-				Error("Couldn't convert environment id of template job to int")
+				Error("Couldn't retrieve environmentID from string")
 			continue
 		}
 		_, err = m.runnerManager.CreateOrUpdateEnvironment(environmentID, uint(desiredIdleRunnersCount), job, false)
@@ -112,6 +116,7 @@ func (m *NomadEnvironmentManager) Load() error {
 			jobLogger.WithError(err).Info("Could not recover job.")
 			continue
 		}
+		jobLogger.Info("Successfully recovered environment")
 	}
 	return nil
 }

runner/manager.go

@@ -355,3 +355,11 @@ func IsEnvironmentTemplateID(jobID string) bool {
 	parts := strings.Split(jobID, "-")
 	return len(parts) == 2 && parts[0] == nomad.TemplateJobPrefix
 }
+
+func EnvironmentIDFromTemplateJobID(id string) (string, error) {
+	parts := strings.Split(id, "-")
+	if len(parts) < 2 {
+		return "", fmt.Errorf("invalid template job id: %w", ErrorInvalidJobID)
+	}
+	return parts[1], nil
+}