[minor] improve flexibility for action expiry handling

Allows jobs to specify the expiry time that is desired for the action in
the configuration file. This also handles increasing the window based on
the job validity time being set in the past.

mig-runner/entity.go

@@ -15,6 +15,10 @@ import (
 	"time"
 )
 
+// The default expiry time for an action launched by the runner if the
+// entity configuration does not include an expiry.
+var defaultExpiry = "5m"
+
 type entity struct {
 	name     string
 	baseDir  string
@@ -30,6 +34,7 @@ type entityConfig struct {
 	Configuration struct {
 		Schedule string
 		Plugin   string
+		Expiry   string
 	}
 }
 
@@ -62,12 +67,21 @@ func (e *entity) launchAction() (err error) {
 		panic(err)
 	}
 
-	// Borrow some logic from the action generator.
-	act.ValidFrom = time.Now().Add(-60 * time.Second).UTC()
-	period, err := time.ParseDuration("2m")
+	// Borrow some logic from the action generator. Set a validation
+	// period starting in the past so our action starts immediately.
+	window := time.Duration(-60 * time.Second)
+	act.ValidFrom = time.Now().Add(window).UTC()
+	exstring := defaultExpiry
+	if e.cfg.Configuration.Expiry != "" {
+		exstring = e.cfg.Configuration.Expiry
+	}
+	period, err := time.ParseDuration(exstring)
 	if err != nil {
 		panic(err)
 	}
+	// Add the window period to the desired expiry since our start
+	// time begins in the past.
+	period += -window
 	act.ExpireAfter = act.ValidFrom.Add(period)
 	asig, err := cli.SignAction(act)
 	if err != nil {