Add list groups REST endpoint

conversion_helpers.go

@@ -433,6 +433,26 @@ func toCompletedTasks(in []*asynq.TaskInfo, pf PayloadFormatter, rf ResultFormat
 	return out
 }
 
+type groupInfo struct {
+	Group string `json:"group"`
+	Size  int    `json:"size"`
+}
+
+func toGroupInfos(in []*asynq.GroupInfo) []*groupInfo {
+	out := make([]*groupInfo, len(in))
+	for i, g := range in {
+		out[i] = toGroupInfo(g)
+	}
+	return out
+}
+
+func toGroupInfo(in *asynq.GroupInfo) *groupInfo {
+	return &groupInfo{
+		Group: in.Group,
+		Size:  in.Size,
+	}
+}
+
 type schedulerEntry struct {
 	ID            string   `json:"id"`
 	Spec          string   `json:"spec"`

group_handlers.go

@@ -0,0 +1,33 @@
+package asynqmon
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/gorilla/mux"
+	"github.com/hibiken/asynq"
+)
+
+type listGroupsResponse struct {
+	Groups []*groupInfo `json:"groups"`
+}
+
+func newListGroupsHandlerFunc(inspector *asynq.Inspector) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		qname := mux.Vars(r)["qname"]
+
+		groups, err := inspector.Groups(qname)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+
+		resp := listGroupsResponse{
+			Groups: toGroupInfos(groups),
+		}
+		if err := json.NewEncoder(w).Encode(resp); err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+	}
+}

handler.go

@@ -176,6 +176,9 @@ func muxRouter(opts Options, rc redis.UniversalClient, inspector *asynq.Inspecto
 
 	api.HandleFunc("/queues/{qname}/tasks/{task_id}", newGetTaskHandlerFunc(inspector, payloadFmt, resultFmt)).Methods("GET")
 
+	// Groups endponts
+	api.HandleFunc("/queues/{qname}/groups", newListGroupsHandlerFunc(inspector)).Methods("GET")
+
 	// Servers endpoints.
 	api.HandleFunc("/servers", newListServersHandlerFunc(inspector, payloadFmt)).Methods("GET")