From 8d531c04cdba9d8dfe0f856d1ee80620e95e9ebb Mon Sep 17 00:00:00 2001
From: Ken Hibino <ken.hibino7@gmail.com>
Date: Sat, 26 Dec 2020 10:05:19 -0800
Subject: [PATCH] Add API endpoints to list scheduler enqueue events

---
 conversion_helpers.go       | 20 ++++++++++++++++++++
 main.go                     |  1 +
 scheduler_entry_handlers.go | 30 +++++++++++++++++++++++++++++-
 3 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/conversion_helpers.go b/conversion_helpers.go
index 21ef339..54025c8 100644
--- a/conversion_helpers.go
+++ b/conversion_helpers.go
@@ -257,3 +257,23 @@ func toSchedulerEntries(in []*asynq.SchedulerEntry) []*SchedulerEntry {
 	}
 	return out
 }
+
+type SchedulerEnqueueEvent struct {
+	TaskID     string `json:"task_id"`
+	EnqueuedAt string `json:"enqueued_at"`
+}
+
+func toSchedulerEnqueueEvent(e *asynq.SchedulerEnqueueEvent) *SchedulerEnqueueEvent {
+	return &SchedulerEnqueueEvent{
+		TaskID:     e.TaskID,
+		EnqueuedAt: e.EnqueuedAt.Format(time.RFC3339),
+	}
+}
+
+func toSchedulerEnqueueEvents(in []*asynq.SchedulerEnqueueEvent) []*SchedulerEnqueueEvent {
+	out := make([]*SchedulerEnqueueEvent, len(in))
+	for i, e := range in {
+		out[i] = toSchedulerEnqueueEvent(e)
+	}
+	return out
+}
diff --git a/main.go b/main.go
index 24f9ba7..d03f9e1 100644
--- a/main.go
+++ b/main.go
@@ -111,6 +111,7 @@ func main() {
 
 	// Scheduler Entry endpoints.
 	api.HandleFunc("/scheduler_entries", newListSchedulerEntriesHandlerFunc(inspector)).Methods("GET")
+	api.HandleFunc("/scheduler_entries/{entry_id}/enqueue_events", newListSchedulerEnqueueEventsHandlerFunc(inspector)).Methods("GET")
 
 	fs := &staticFileServer{staticPath: "ui/build", indexPath: "index.html"}
 	router.PathPrefix("/").Handler(fs)
diff --git a/scheduler_entry_handlers.go b/scheduler_entry_handlers.go
index fb38554..e4d888b 100644
--- a/scheduler_entry_handlers.go
+++ b/scheduler_entry_handlers.go
@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"net/http"
 
+	"github.com/gorilla/mux"
 	"github.com/hibiken/asynq"
 )
 
@@ -26,6 +27,33 @@ func newListSchedulerEntriesHandlerFunc(inspector *asynq.Inspector) http.Handler
 		} else {
 			payload["entries"] = toSchedulerEntries(entries)
 		}
-		json.NewEncoder(w).Encode(payload)
+		if err := json.NewEncoder(w).Encode(payload); err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	}
+}
+
+type ListSchedulerEnqueueEventsResponse struct {
+	Events []*SchedulerEnqueueEvent `json:"events"`
+}
+
+func newListSchedulerEnqueueEventsHandlerFunc(inspector *asynq.Inspector) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		entryID := mux.Vars(r)["entry_id"]
+		pageSize, pageNum := getPageOptions(r)
+		events, err := inspector.ListSchedulerEnqueueEvents(
+			entryID, asynq.PageSize(pageSize), asynq.Page(pageNum))
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		resp := ListSchedulerEnqueueEventsResponse{
+			Events: toSchedulerEnqueueEvents(events),
+		}
+		if err := json.NewEncoder(w).Encode(resp); err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
 	}
 }