feat(2.2.0): new request type: stats, implement metrics

Makefile

@@ -1,6 +1,6 @@
 VERSION = $(shell cat ./version.json | jq .version | tr -d '"')
 GIT_COMMIT = $(shell git rev-parse --short HEAD)
-BUILD_DATE = $(shell go run ./cmd/builddate.go)
+BUILD_DATE = $(shell go run ./cmd/build-date.go)
 
 HOME_OS ?= $(shell go env GOOS)
 ifeq ($(HOME_OS),linux)
@@ -22,7 +22,7 @@ endif
 # Usage: `make build`
 build:
 	@echo Building project...
-	go build -ldflags "-s -w -X main.version=${VERSION} -X main.commitHash=${GIT_COMMIT} -X \"main.buildDate=${BUILD_DATE}\"" -o $(TARGET_FILE)
+	go build -ldflags "-s -w -X nino.sh/timeouts/pkg.Version=${VERSION} -X nino.sh/timeouts/pkg.CommitHash=${GIT_COMMIT} -X \"nino.sh/timeouts/pkg.BuildDate=${BUILD_DATE}\"" -o $(TARGET_FILE)
 	@echo Built project! Use "$(TARGET_FILE)" to execute the project.
 
 # Usage: `make clean`

go.mod

@@ -6,11 +6,19 @@ require (
 	github.com/go-redis/redis/v8 v8.11.4
 	github.com/gorilla/websocket v1.5.0
 	github.com/joho/godotenv v1.4.0
+	github.com/prometheus/client_golang v1.12.1
 	github.com/sirupsen/logrus v1.8.1
 )
 
 require (
+	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.1.2 // indirect
 	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
-	golang.org/x/sys v0.0.0-20210423082822-04245dca01da // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
+	github.com/prometheus/client_model v0.2.0 // indirect
+	github.com/prometheus/common v0.32.1 // indirect
+	github.com/prometheus/procfs v0.7.3 // indirect
+	golang.org/x/sys v0.0.0-20220114195835-da31bd327af9 // indirect
+	google.golang.org/protobuf v1.26.0 // indirect
 )

main.go

@@ -25,6 +25,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"github.com/joho/godotenv"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/sirupsen/logrus"
 	"net/http"
 	"nino.sh/timeouts/pkg"
@@ -34,12 +35,6 @@ import (
 	"time"
 )
 
-var (
-	version    string
-	commitHash string
-	buildDate  string
-)
-
 func init() {
 	// Setup logging
 	if os.Getenv("DEBUG") == "true" {
@@ -58,7 +53,7 @@ func init() {
 		}
 	}
 
-	logrus.Infof("Using v%s (commit: %s, built at: %s)", version, commitHash, buildDate)
+	logrus.Infof("Using v%s (commit: %s, built at: %s)", pkg.Version, pkg.CommitHash, pkg.BuildDate)
 }
 
 func fallbackEnv(envString string, fallback string) string {
@@ -77,7 +72,14 @@ func main() {
 	// Create a new `Server` instance
 	pkg.NewServer()
 
+	enableMetrics := pkg.SetupMetrics()
+
 	http.HandleFunc("/", pkg.HandleRequest)
+
+	if enableMetrics {
+		http.HandleFunc("/metrics", promhttp.Handler().ServeHTTP)
+	}
+
 	server := &http.Server{
 		Addr:    fmt.Sprintf(":%s", fallbackEnv(os.Getenv("PORT"), "4025")),
 		Handler: nil,

pkg/client.go

@@ -26,6 +26,7 @@ import (
 	"fmt"
 	"github.com/gorilla/websocket"
 	"github.com/sirupsen/logrus"
+	"runtime"
 	"strings"
 	"sync"
 	"time"
@@ -156,5 +157,18 @@ func (c *Client) HandleMessage(msg Message) {
 		{
 			c.HandleTimeout(toTimeout(msg.Data.(map[string]interface{})))
 		}
+
+	case Stats:
+		{
+			c.WriteMessage(Message{
+				OP: Stats,
+				Data: map[string]interface{}{
+					"go_version": strings.TrimPrefix(runtime.GOOS, "go"),
+					"version":    Version,
+					"commit_sha": CommitHash,
+					"build_date": BuildDate,
+				},
+			})
+		}
 	}
 }

pkg/constants.go

@@ -0,0 +1,7 @@
+package pkg
+
+var (
+	Version    = "master"
+	CommitHash = "???"
+	BuildDate  = "???"
+)

pkg/metrics.go

@@ -0,0 +1,58 @@
+// Copyright (c) 2021 Nino
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+package pkg
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/sirupsen/logrus"
+	"os"
+)
+
+var (
+	TimeoutMetric = prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "nino_timeouts_timeouts",
+		Help: "How many timeouts the service is handling",
+	})
+
+	TimeoutLatencyMetric = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Name: "nino_timeouts_average_ws_latency",
+		Help: "The latency to process a WebSocket message.",
+	})
+)
+
+func SetupMetrics() bool {
+	enabled, ok := os.LookupEnv("NINO_TIMEOUTS_METRICS_ENABLED")
+
+	if !ok {
+		logrus.Infof("`NINO_TIMEOUTS_METRICS_ENABLED` was not defined, disabling metrics...")
+		return false
+	}
+
+	if enabled == "false" || enabled == "0" {
+		logrus.Infof("Not enabling metrics due to `NINO_TIMEOUTS_METRICS_ENABLED` being disabled.")
+		return false
+	}
+
+	logrus.Infof("Now setting up collector registry...")
+	prometheus.MustRegister(TimeoutMetric, TimeoutLatencyMetric)
+
+	return true
+}

pkg/socket.go

@@ -23,6 +23,7 @@ package pkg
 import (
 	"context"
 	"encoding/json"
+	"github.com/go-redis/redis/v8"
 	"github.com/gorilla/websocket"
 	"github.com/sirupsen/logrus"
 	"net/http"
@@ -67,8 +68,23 @@ func NewServer() {
 	// Overwrite queue based off Redis
 	data, err := Redis.Connection.Get(context.TODO(), "nino:timeouts").Result()
 	if err != nil {
-		logrus.Warnf("Unable to retrieve all timeouts, are we connected?\n%v", err)
-		return
+		if err == redis.Nil {
+			logrus.Warnf("We have retrieved `null` when fetching for timeouts, skipping as empty queue.")
+
+			// Set it to an empty array
+			err = Redis.Connection.HMSet(context.TODO(), "nino:timeouts", []Timeout{}).Err()
+			if err != nil {
+				logrus.Errorf("Unable to set data as an empty array. :<")
+				return
+			}
+
+			logrus.Infof("Queue has been set in Redis, now starting fresh!")
+			Server.Queue = make([]Timeout, 0)
+			return
+		} else {
+			logrus.Warnf("Unable to retrieve all timeouts, are we connected?\n%v", err)
+			return
+		}
 	}
 
 	// serialize output to []Timeout{}

pkg/types.go

@@ -27,6 +27,7 @@ const (
 	Apply
 	Request
 	RequestAll
+	Stats
 )
 
 type Message struct {

version.json

@@ -1,3 +1,3 @@
 {
-  "version": "2.1.0"
+  "version": "2.2.0"
 }