From 97dcc95a2ff9122ec750edd05d5835fbdace6e6e Mon Sep 17 00:00:00 2001
From: Lou Knauer <lou.knauer@gmx.de>
Date: Fri, 7 Jan 2022 08:52:55 +0100
Subject: [PATCH] add query api endpoint

---
 api.go | 105 +++++++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 79 insertions(+), 26 deletions(-)

diff --git a/api.go b/api.go
index 8dc72c2..6280243 100644
--- a/api.go
+++ b/api.go
@@ -31,7 +31,7 @@ type ApiRequestBody struct {
 }
 
 type ApiMetricData struct {
-	Error *string `json:"error"`
+	Error *string `json:"error,omitempty"`
 	From  int64   `json:"from"`
 	To    int64   `json:"to"`
 	Data  []Float `json:"data"`
@@ -339,33 +339,86 @@ func handleAllNodes(rw http.ResponseWriter, r *http.Request) {
 	}
 }
 
-// func handleCheckpoint(rw http.ResponseWriter, r *http.Request) {
-// 	vars := mux.Vars(r)
-// 	from, err := strconv.ParseInt(vars["from"], 10, 64)
-// 	if err != nil {
-// 		http.Error(rw, err.Error(), http.StatusBadRequest)
-// 		return
-// 	}
-// 	to, err := strconv.ParseInt(vars["to"], 10, 64)
-// 	if err != nil {
-// 		http.Error(rw, err.Error(), http.StatusBadRequest)
-// 		return
-// 	}
+type ApiQueryRequest struct {
+	Cluster string     `json:"cluster"`
+	From    int64      `json:"from"`
+	To      int64      `json:"to"`
+	Queries []ApiQuery `json:"queries"`
+}
 
-// 	log.Println("Checkpoint creation started...")
-// 	n, err := memoryStore.ToCheckpoint(conf.Checkpoints.RootDir, from, to)
-// 	if err != nil {
-// 		log.Printf("Checkpoint creation failed: %s\n", err.Error())
-// 		rw.WriteHeader(http.StatusInternalServerError)
-// 		return
-// 	} else {
-// 		log.Printf("Checkpoint finished (%d files)\n", n)
-// 	}
+type ApiQueryResponse struct {
+	ApiMetricData
+	Query *ApiQuery `json:"query"`
+}
 
-// 	memoryStore.FreeAll()
+type ApiQuery struct {
+	Metric     string   `json:"metric"`
+	Hostname   string   `json:"hostname"`
+	Type       *string  `json:"type,omitempty"`
+	TypeIds    []string `json:"type-ids,omitempty"`
+	SubType    *string  `json:"subtype,omitempty"`
+	SubTypeIds []string `json:"subtype-ids,omitempty"`
+}
 
-// 	rw.WriteHeader(http.StatusOK)
-// }
+func handleQuery(rw http.ResponseWriter, r *http.Request) {
+	var err error
+	var req ApiQueryRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(rw, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	response := make([]ApiQueryResponse, 0, len(req.Queries))
+	for _, query := range req.Queries {
+		res := ApiQueryResponse{
+			Query: &query,
+		}
+
+		sel := Selector{SelectorElement{String: req.Cluster}, SelectorElement{String: query.Hostname}}
+		if query.Type != nil {
+			if len(query.TypeIds) == 1 {
+				sel = append(sel, SelectorElement{String: query.TypeIds[0]})
+			} else {
+				ids := make([]string, len(query.TypeIds))
+				for i, id := range query.TypeIds {
+					ids[i] = *query.Type + id
+				}
+				sel = append(sel, SelectorElement{Group: ids})
+			}
+
+			if query.SubType != nil {
+				if len(query.SubTypeIds) == 1 {
+					sel = append(sel, SelectorElement{String: query.SubTypeIds[0]})
+				} else {
+					ids := make([]string, len(query.SubTypeIds))
+					for i, id := range query.SubTypeIds {
+						ids[i] = *query.SubType + id
+					}
+					sel = append(sel, SelectorElement{Group: ids})
+				}
+			}
+		}
+
+		res.Data, res.From, res.To, err = memoryStore.Read(sel, query.Metric, req.From, req.To)
+		if err != nil {
+			msg := err.Error()
+			res.Error = &msg
+			response = append(response, res)
+			continue
+		}
+
+		res.AddStats()
+		response = append(response, res)
+	}
+
+	rw.Header().Set("Content-Type", "application/json")
+	bw := bufio.NewWriter(rw)
+	defer bw.Flush()
+	if err := json.NewEncoder(bw).Encode(response); err != nil {
+		log.Print(err)
+		return
+	}
+}
 
 func authentication(next http.Handler, publicKey ed25519.PublicKey) http.Handler {
 	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
@@ -405,7 +458,7 @@ func StartApiServer(address string, ctx context.Context) error {
 	r.HandleFunc("/api/{cluster}/peek", handlePeek)
 	r.HandleFunc("/api/{cluster}/{from:[0-9]+}/{to:[0-9]+}/all-nodes", handleAllNodes)
 	r.HandleFunc("/api/write", handleWrite)
-	// r.HandleFunc("/api/{from:[0-9]+}/{to:[0-9]+}/checkpoint", handleCheckpoint)
+	r.HandleFunc("/api/query", handleQuery)
 
 	server := &http.Server{
 		Handler:      r,