client: add support for task group checks

When tasks are checked for script checks, we walk back through their
task group to see if there are script checks associated with the
task. If so, we'll spin off script check tasklets for them. The
group-level service and any restart behaviors it needs are entirely
encapsulated within the group service hook.

Author: tgross

client/allocrunner/taskrunner/script_check_hook.go

@@ -71,6 +71,32 @@ func newScriptCheckHook(c scriptCheckHookConfig) *scriptCheckHook {
 			scriptChecks[sc.id] = sc
 		}
 	}
+
+	// Walk back through the task group to see if there are script checks
+	// associated with the task. If so, we'll create scriptCheck tasklets
+	// for them. The group-level service and any check restart behaviors it
+	// needs are entirely encapsulated within the group service hook which
+	// watches Consul for status changes.
+	tg := c.alloc.Job.LookupTaskGroup(c.alloc.TaskGroup)
+	for _, service := range tg.Services {
+		for _, check := range service.Checks {
+			if check.Type != structs.ServiceCheckScript {
+				continue
+			}
+			if check.TaskName != c.task.Name {
+				continue
+			}
+			groupTaskName := "group-" + tg.Name
+			sc := newScriptCheck(&scriptCheckConfig{
+				allocID:  c.alloc.ID,
+				taskName: groupTaskName,
+				service:  service,
+				check:    check,
+				agent:    c.consul,
+			})
+			scriptChecks[sc.id] = sc
+		}
+	}
 	if len(scriptChecks) == 0 {
 		return nil // the caller should not register this hook
 	}