fix(master): refuse jobs for revoked agents, signal revoked jobs, agent start time wins (#7)

internal/master/web/server.go

@@ -36,7 +36,8 @@ type Store interface {
 	ListJobs(ctx context.Context, f model.JobFilter) ([]model.Job, error)
 	ListAgents(ctx context.Context) ([]model.Agent, error)
 	CreateAgent(ctx context.Context, name, tokenHash string) (model.Agent, error)
-	RevokeAgent(ctx context.Context, id int64, at time.Time) error
+	// RevokeAgent returns the IDs of the jobs it failed.
+	RevokeAgent(ctx context.Context, id int64, at time.Time) ([]int64, error)
 }
 
 // Hub reports and controls live agent connections. *hub.Hub satisfies it.
@@ -389,13 +390,17 @@ func (s *Server) revokeAgent(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "invalid agent id", http.StatusBadRequest)
 		return
 	}
-	if err := s.store.RevokeAgent(r.Context(), id, s.now()); err != nil {
+	failedJobs, err := s.store.RevokeAgent(r.Context(), id, s.now())
+	if err != nil {
 		s.fail(w, err)
 		return
 	}
 	s.hub.Disconnect(id)
 	s.broker.Publish(events.Services) // the agent's services were marked removed
 	s.broker.Publish(events.Jobs)     // the agent's active jobs were failed
+	for _, jobID := range failedJobs {
+		s.broker.Publish(events.JobTopic(jobID)) // open job pages show the failure
+	}
 	http.Redirect(w, r, "/agents", http.StatusSeeOther)
 }