Very basic initial API endpoint

.gitignore

@@ -4,6 +4,7 @@
 *.dll
 *.so
 *.dylib
+/cc-metric-store
 
 # Test binary, built with `go test -c`
 *.test

api.go

@@ -0,0 +1,104 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"log"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/gorilla/mux"
+)
+
+type HostData struct {
+	Host  string    `json:"host"`
+	Start int64     `json:"start"`
+	Data  []float64 `json:"data"`
+}
+
+type MetricData struct {
+	Hosts []HostData `json:"hosts"`
+}
+
+type TimeseriesNodeResponse map[string]MetricData
+
+func handleTimeseriesNode(rw http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	cluster := vars["cluster"]
+	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
+	}
+
+	values := r.URL.Query()
+	hosts := values["host"]
+	metrics := values["metric"]
+	if len(hosts) < 1 || len(metrics) < 1 {
+		http.Error(rw, "no hosts or metrics specified", http.StatusBadRequest)
+		return
+	}
+
+	response := TimeseriesNodeResponse{}
+	store := metricStores["node"]
+	for _, metric := range metrics {
+		hostsdata := []HostData{}
+		for _, host := range hosts {
+			key := cluster + ":" + host
+			data, start, err := store.GetMetric(key, metric, from, to)
+			if err != nil {
+				http.Error(rw, err.Error(), http.StatusInternalServerError)
+				return
+			}
+
+			hostsdata = append(hostsdata, HostData{
+				Host:  host,
+				Start: start,
+				Data:  data,
+			})
+		}
+		response[metric] = MetricData{
+			Hosts: hostsdata,
+		}
+	}
+
+	rw.Header().Set("Content-Type", "application/json")
+	err = json.NewEncoder(rw).Encode(response)
+	if err != nil {
+		log.Println(err.Error())
+	}
+}
+
+func StartApiServer(address string, done chan bool) error {
+	r := mux.NewRouter()
+
+	r.HandleFunc("/api/{cluster}/timeseries/node/{from:[0-9]+}/{to:[0-9]+}", handleTimeseriesNode)
+
+	server := &http.Server{
+		Handler:      r,
+		Addr:         address,
+		WriteTimeout: 15 * time.Second,
+		ReadTimeout:  15 * time.Second,
+	}
+
+	go func() {
+		log.Printf("API http endpoint listening on '%s'\n", address)
+		err := server.ListenAndServe()
+		if err != nil && err != http.ErrServerClosed {
+			log.Println(err)
+		}
+	}()
+
+	for {
+		_ = <-done
+		err := server.Shutdown(context.Background())
+		log.Println("API server shut down")
+		return err
+	}
+}

go.mod

@@ -4,6 +4,7 @@ go 1.16
 
 require (
 	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/gorilla/mux v1.8.0
 	github.com/nats-io/nats-server/v2 v2.2.6 // indirect
 	github.com/nats-io/nats.go v1.11.0
 )

go.sum

@@ -11,6 +11,8 @@ github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMyw
 github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/gorilla/mux v1.8.0 h1:i40aqfkR1h2SlN9hojwV5ZA91wcXFOvkdNIeFDP5koI=
+github.com/gorilla/mux v1.8.0/go.mod h1:DVbg23sWSpFRCP0SfiEN6jmj59UnW/n46BH5rLB71So=
 github.com/klauspost/compress v1.11.12 h1:famVnQVu7QwryBN4jNseQdUKES71ZAOnB6UQQJPZvqk=
 github.com/klauspost/compress v1.11.12/go.mod h1:aoV0uJVorq1K+umq18yTdKaF57EivdYsUV+/s2qKfXs=
 github.com/minio/highwayhash v1.0.1 h1:dZ6IIu8Z14VlC0VpfKofAhCy74wu/Qb5gcn52yWoz/0=

lineprotocol/receiver.go

@@ -89,10 +89,10 @@ func ReceiveNats(address string, handleLine func(line *Line), done chan bool) er
 		return err
 	}
 
+	log.Printf("NATS subscription to 'updates' on '%s' established\n", address)
 	for {
-		stop := <-done
+		_ = <-done
-		if stop {
+		log.Println("NATS connection closed")
-			return nil
+		return nil
-		}
 	}
 }

metric-store.go

@@ -7,6 +7,7 @@ import (
 	"log"
 	"os"
 	"os/signal"
+	"sync"
 	"syscall"
 
 	"github.com/ClusterCockpit/cc-metric-store/lineprotocol"
@@ -61,7 +62,7 @@ func buildKey(line *lineprotocol.Line) (string, error) {
 }
 
 func handleLine(line *lineprotocol.Line) {
-	// log.Printf("line: %v\n", line)
+	log.Printf("line: %v (t=%d)\n", line, line.Ts.Unix())
 
 	store := metricStores[line.Measurement]
 	key, err := buildKey(line)
@@ -85,10 +86,22 @@ func main() {
 	go func() {
 		_ = <-sigs
 		done <- true
+		close(done)
+		log.Println("shuting down")
+	}()
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+
+	go func() {
+		StartApiServer(":8080", done)
+		wg.Done()
 	}()
 
 	err := lineprotocol.ReceiveNats("nats://localhost:4222", handleLine, done)
 	if err != nil {
 		log.Fatal(err)
 	}
+
+	wg.Wait()
 }