test built-in rpc

broker-service/cmd/api/event/emitter.go

@@ -0,0 +1,53 @@
+package event
+
+import (
+	"log"
+
+	amqp "github.com/rabbitmq/amqp091-go"
+)
+
+type Emitter struct {
+	conn *amqp.Connection
+}
+
+func NewEmitter(conn *amqp.Connection) (Emitter, error) {
+	emitter := Emitter{
+		conn: conn,
+	}
+
+	err := emitter.setup()
+	if err != nil {
+		return Emitter{}, err
+	}
+	return emitter, err
+}
+
+func (emitter *Emitter) setup() error {
+	channel, err := emitter.conn.Channel()
+	if err != nil {
+		return err
+	}
+	defer channel.Close()
+
+	return declaireExchange(channel)
+}
+
+func (emitter *Emitter) Push(event string, severity string) error {
+	ch, err := emitter.conn.Channel()
+	if err != nil {
+		return err
+	}
+	defer ch.Close()
+
+	log.Println("Pushing to channel")
+
+	err = ch.Publish("logs_topic", severity, false, false, amqp.Publishing{
+		ContentType: "text/plain",
+		Body:        []byte(event),
+	})
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

broker-service/cmd/api/event/event.go

@@ -0,0 +1,28 @@
+package event
+
+import (
+	amqp "github.com/rabbitmq/amqp091-go"
+)
+
+func declaireExchange(ch *amqp.Channel) error {
+	return ch.ExchangeDeclare(
+		"logs_topic", // name
+		"topic",      // type
+		true,         // durable?
+		false,        // auto-deleted?
+		false,        // internal?
+		false,        // no-wait?
+		nil,          // arguments?
+	)
+}
+
+func declaireRandomQueue(ch *amqp.Channel) (amqp.Queue, error) {
+	return ch.QueueDeclare(
+		"",    // name
+		false, // durable
+		false, // delete when unused
+		true,  // exclusive
+		false, // nowait
+		nil,   // table
+	)
+}

broker-service/cmd/api/handlers.go

@@ -1,11 +1,15 @@
 package main
 
 import (
+	"broker/cmd/api/event"
 	"bytes"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"log"
 	"net/http"
+	"net/rpc"
+	"time"
 )
 
 type RequestPayload struct {
@@ -53,8 +57,12 @@ func (app *Config) HandleSubmission(w http.ResponseWriter, r *http.Request) {
 	switch requestPayload.Action {
 	case "auth":
 		app.authenticate(w, requestPayload.Auth)
-	case "log":
+	case "logHttp": // 2729 us
 		app.LogItem(w, requestPayload.Log)
+	case "logRabbit": // 10007 us
+		app.logEventViaRabbit(w, requestPayload.Log)
+	case "logRpc": // 555 us
+		app.logItemViaRPC(w, requestPayload.Log)
 	case "mail":
 		app.SendMail(w, requestPayload.Mail)
 	default:
@@ -78,6 +86,8 @@ func (app *Config) authenticate(w http.ResponseWriter, a AuthPayload) {
 
 func (app *Config) LogItem(w http.ResponseWriter, entry LogPayload) {
 	log.Println(entry)
+	now := time.Now()
+	entry.Data += fmt.Sprintf("HTTP sent date %d", now.UnixMicro())
 	loggerService := Microservice{
 		Input: entry,
 		Addr:  "http://logger-service/log",
@@ -176,3 +186,70 @@ func (app *Config) callService(w http.ResponseWriter, ms Microservice) {
 
 	app.writeJSON(w, http.StatusOK, payload)
 }
+
+func (app *Config) logEventViaRabbit(w http.ResponseWriter, l LogPayload) {
+	now := time.Now()
+	l.Data += fmt.Sprintf("Rabbit sent date %d", now.UnixMicro())
+	err := app.pushToQueue(l.Name, l.Data)
+	if err != nil {
+		app.errorJSON(w, err)
+		return
+	}
+
+	var payload jsonResponse
+	payload.Error = false
+	payload.Message = "logged via RabbitMQ"
+
+	app.writeJSON(w, http.StatusOK, payload)
+}
+
+func (app *Config) pushToQueue(name, msg string) error {
+	emitter, err := event.NewEmitter(app.Rabbit)
+	if err != nil {
+		return err
+	}
+
+	payload := LogPayload{
+		Name: name,
+		Data: msg,
+	}
+
+	j, _ := json.MarshalIndent(&payload, "", "\t")
+	err = emitter.Push(string(j), "log.INFO")
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+type RPCPayload struct {
+	Name string
+	Data string
+}
+
+func (app *Config) logItemViaRPC(w http.ResponseWriter, l LogPayload) {
+	client, err := rpc.Dial("tcp", "logger-service:5001")
+	if err != nil {
+		app.errorJSON(w, err)
+		return
+	}
+	defer client.Close()
+
+	now := time.Now()
+	l.Data += fmt.Sprintf("RPC sent date %d", now.UnixMicro())
+	rpcPayload := RPCPayload(l)
+
+	var result string
+	err = client.Call("RPCServer.LogInfo", rpcPayload, &result)
+	if err != nil {
+		app.errorJSON(w, err)
+		return
+	}
+
+	var payload jsonResponse
+	payload.Error = false
+	payload.Message = "logged via RPC"
+
+	app.writeJSON(w, http.StatusOK, payload)
+}

broker-service/cmd/api/main.go

@@ -3,15 +3,32 @@ package main
 import (
 	"fmt"
 	"log"
+	"math"
 	"net/http"
+	"os"
+	"time"
+
+	amqp "github.com/rabbitmq/amqp091-go"
 )
 
 const webPort = "80"
 
-type Config struct{}
+type Config struct {
+	Rabbit *amqp.Connection
+}
 
 func main() {
-	app := Config{}
+	// try to connect to rabbitmq
+	rabbitConn, err := connect()
+	if err != nil {
+		log.Println(err)
+		os.Exit(1)
+	}
+	defer rabbitConn.Close()
+	log.Println("Connected to RabbitMQ")
+	app := Config{
+		Rabbit: rabbitConn,
+	}
 
 	log.Printf("Starting broker service on port %s\n", webPort)
 
@@ -21,8 +38,36 @@ func main() {
 		Handler: app.routes(),
 	}
 
-	err := srv.ListenAndServe()
+	err = srv.ListenAndServe()
 	if err != nil {
 		log.Panic(err)
 	}
 }
+
+func connect() (*amqp.Connection, error) {
+	var counts int64
+	var connection *amqp.Connection
+
+	// don't continue until rabbit is ready
+	for {
+		c, err := amqp.Dial("amqp://guest:guest@rabbitmq") // XXX: credentials
+		if err != nil {
+			fmt.Println("RabbitMQ not yet ready...")
+			counts++
+		} else {
+			connection = c
+			break
+		}
+
+		if counts > 5 {
+			fmt.Println(err)
+			return nil, err
+		}
+
+		backOff := time.Duration(math.Pow(float64(counts), 2) * float64(time.Second))
+		log.Println("backing off...")
+		time.Sleep(backOff)
+	}
+
+	return connection, nil
+}

broker-service/go.mod

@@ -6,3 +6,5 @@ require (
 	github.com/go-chi/chi/v5 v5.1.0
 	github.com/go-chi/cors v1.2.1
 )
+
+require github.com/rabbitmq/amqp091-go v1.10.0

broker-service/go.sum

@@ -2,3 +2,7 @@ github.com/go-chi/chi/v5 v5.1.0 h1:acVI1TYaD+hhedDJ3r54HyA6sExp3HfXq7QWEEY/xMw=
 github.com/go-chi/chi/v5 v5.1.0/go.mod h1:DslCQbL2OYiznFReuXYUmQ2hGd1aDpCnlMNITLSKoi8=
 github.com/go-chi/cors v1.2.1 h1:xEC8UT3Rlp2QuWNEr4Fs/c2EAGVKBwy/1vHx3bppil4=
 github.com/go-chi/cors v1.2.1/go.mod h1:sSbTewc+6wYHBBCW7ytsFSn836hqM7JxpglAy2Vzc58=
+github.com/rabbitmq/amqp091-go v1.10.0 h1:STpn5XsHlHGcecLmMFCtg7mqq0RnD+zFr4uzukfVhBw=
+github.com/rabbitmq/amqp091-go v1.10.0/go.mod h1:Hy4jKW5kQART1u+JkDTF9YYOQUHXqMuhrgxOEeS7G4o=
+go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
+go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=

front-end/cmd/web/templates/test.page.gohtml

@@ -9,7 +9,9 @@
 
                 <a id="brokerBtn" class="btn btn-outline-secondary" href="javascript:void(0);">Test Broker</a>
                 <a id="authBrokerBtn" class="btn btn-outline-secondary" href="javascript:void(0);">Test Auth</a>
-                <a id="logBtn" class="btn btn-outline-secondary" href="javascript:void(0);">Test Log</a>
+                <a id="logHttpBtn" class="btn btn-outline-secondary" href="javascript:void(0);">Test HTTP Log</a>
+                <a id="logRabbitBtn" class="btn btn-outline-secondary" href="javascript:void(0);">Test Rabbit Log</a>
+                <a id="logRpcBtn" class="btn btn-outline-secondary" href="javascript:void(0);">Test RPC Log</a>
                 <a id="mailBtn" class="btn btn-outline-secondary" href="javascript:void(0);">Test Mail</a>
 
                 <div id="output" class="mt-5" style="outline: 1px solid silver; padding: 2em;">
@@ -39,6 +41,9 @@
         let brokerBtn = document.getElementById("brokerBtn");
         let authBrokerBtn = document.getElementById("authBrokerBtn");
         let mailBtn = document.getElementById("mailBtn");
+        let logHttpBtn = document.getElementById("logHttpBtn");
+        let logRabbitBtn = document.getElementById("logRabbitBtn");
+        let logRpcBtn = document.getElementById("logRpcBtn");
         let output = document.getElementById("output");
         let sent = document.getElementById("payload");
         let received = document.getElementById("received");
@@ -95,9 +100,73 @@
                 });
         });
 
-        logBtn.addEventListener("click", () => {
+        logHttpBtn.addEventListener("click", () => {
             const payload = {
-                action: "log",
+                action: "logHttp",
+                log: {
+                    name: "event",
+                    data: "some kind of data",
+                }
+            };
+            const headers = new Headers();
+            headers.append("Content-Type", "application/json");
+            const body = {
+                method: 'POST',
+                body: JSON.stringify(payload),
+                headers: headers,
+            }
+            fetch("http:\/\/localhost:8080/handle", body)
+            .then((response) => response.json())
+                .then((data) => {
+                    sent.innerHTML = JSON.stringify(payload, undefined, 4);
+                    received.innerHTML = JSON.stringify(data, undefined, 4);
+                    if (data.error) {
+                        console.log(data.message);
+                        output.innerHTML += `<br><strong>Error:</strong>: ${data.message}`;
+                    } else {
+                        output.innerHTML += `<br><strong>Response from broker service</strong>: ${data.message}`;
+                    }
+                })
+                .catch((error) => {
+                    output.innerHTML += "<br><br>Error: " + error;
+                });
+        });
+
+        logRabbitBtn.addEventListener("click", () => {
+            const payload = {
+                action: "logRabbit",
+                log: {
+                    name: "event",
+                    data: "some kind of data",
+                }
+            };
+            const headers = new Headers();
+            headers.append("Content-Type", "application/json");
+            const body = {
+                method: 'POST',
+                body: JSON.stringify(payload),
+                headers: headers,
+            }
+            fetch("http:\/\/localhost:8080/handle", body)
+            .then((response) => response.json())
+                .then((data) => {
+                    sent.innerHTML = JSON.stringify(payload, undefined, 4);
+                    received.innerHTML = JSON.stringify(data, undefined, 4);
+                    if (data.error) {
+                        console.log(data.message);
+                        output.innerHTML += `<br><strong>Error:</strong>: ${data.message}`;
+                    } else {
+                        output.innerHTML += `<br><strong>Response from broker service</strong>: ${data.message}`;
+                    }
+                })
+                .catch((error) => {
+                    output.innerHTML += "<br><br>Error: " + error;
+                });
+        });
+
+        logRpcBtn.addEventListener("click", () => {
+            const payload = {
+                action: "logRpc",
                 log: {
                     name: "event",
                     data: "some kind of data",

listener-service/event/consumer.go

@@ -33,6 +33,7 @@ func (consumer *Consumer) setup() error {
 	if err != nil {
 		return err
 	}
+	defer channel.Close()
 
 	return declaireExchange(channel)
 }

listener-service/listener-service.dockerfile

@@ -0,0 +1,8 @@
+FROM alpine:latest
+
+RUN mkdir /app
+
+COPY listenerApp /app
+
+CMD ["/app/listenerApp"]
+

listener-service/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"listener/event"
 	"log"
 	"math"
 	"os"
@@ -21,10 +22,19 @@ func main() {
 	log.Println("Connected to RabbitMQ")
 
 	// start listening for messages
-
+	log.Println("Listening for and consuming RabbitMQ messages...")
 	// create consumer
 
+	consumer, err := event.NewConsumer(rabbitConn)
+	if err != nil {
+		log.Panic(err)
+	}
+
 	// watch the queue and consume events
+	err = consumer.Listen([]string{"log.INFO", "log.WARNING", "log.ERROR"})
+	if err != nil {
+		log.Println(err)
+	}
 }
 
 func connect() (*amqp.Connection, error) {
@@ -33,7 +43,7 @@ func connect() (*amqp.Connection, error) {
 
 	// don't continue until rabbit is ready
 	for {
-		c, err := amqp.Dial("amqp://guest:guest@localhost") // XXX: credentials
+		c, err := amqp.Dial("amqp://guest:guest@rabbitmq") // XXX: credentials
 		if err != nil {
 			fmt.Println("RabbitMQ not yet ready...")
 			counts++

logger-service/cmd/api/handlers.go

@@ -1,9 +1,11 @@
 package main
 
 import (
+	"fmt"
 	"log"
 	"logger/data"
 	"net/http"
+	"time"
 )
 
 type JSONPayload struct {
@@ -27,6 +29,9 @@ func (app *Config) WriteLog(w http.ResponseWriter, r *http.Request) {
 		Data: requestPayload.Data,
 	}
 
+	now := time.Now()
+	event.Data += fmt.Sprintf(" received date %d", now.UnixMicro())
+
 	log.Println("event", event)
 
 	err = app.Models.LogEntry.Insert(event)

logger-service/cmd/api/main.go

@@ -5,7 +5,9 @@ import (
 	"fmt"
 	"log"
 	"logger/data"
+	"net"
 	"net/http"
+	"net/rpc"
 	"time"
 
 	"go.mongodb.org/mongo-driver/bson"
@@ -49,6 +51,14 @@ func main() {
 		Models: data.New(client),
 	}
 
+	// Register the RPC server
+	err = rpc.Register(new(RPCServer))
+	if err != nil {
+		panic(err)
+	}
+
+	go app.rpcListen()
+
 	// start web server
 	log.Println("Starting service on port", webPort)
 	app.serve()
@@ -88,3 +98,20 @@ func connectToMongo() (*mongo.Client, error) {
 
 	return client, nil
 }
+
+func (app *Config) rpcListen() error {
+	log.Println("Starting RPC server on port ", rpcPort)
+	listen, err := net.Listen("tcp", fmt.Sprintf("0.0.0.0:%s", rpcPort))
+	if err != nil {
+		return err
+	}
+
+	defer listen.Close()
+	for {
+		rpcConn, err := listen.Accept()
+		if err != nil {
+			continue
+		}
+		go rpc.ServeConn(rpcConn)
+	}
+}

logger-service/cmd/api/rpc.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"logger/data"
+	"time"
+)
+
+type RPCServer struct{}
+
+type RPCPayload struct {
+	Name string
+	Data string
+}
+
+func (r *RPCServer) LogInfo(payload RPCPayload, resp *string) error {
+	collection := client.Database("logs").Collection("logs")
+
+	now := time.Now()
+	payload.Data += fmt.Sprintf(" received date %d", now.UnixMicro())
+
+	_, err := collection.InsertOne(context.TODO(), data.LogEntry{
+		Name:      payload.Name,
+		Data:      payload.Data,
+		CreatedAt: time.Now(),
+	})
+	if err != nil {
+		log.Println("error writing to mongo", err)
+		return err
+	}
+
+	*resp = "Processed payload via RPC:" + payload.Name
+
+	return nil
+}

project/Makefile

@@ -3,6 +3,7 @@ BROKER_BINARY=brokerApp
 AUTH_BINARY=authApp
 LOGGER_BINARY=loggerApp
 MAIL_BINARY=mailApp
+LISTENER_BINARY=listenerApp
 
 ## up: starts all containers in the background without forcing build
 up:
@@ -11,7 +12,7 @@ up:
 	@echo "Docker images started!"
 
 ## up_build: stops docker-compose (if running), builds all projects and starts docker compose
-up_build: build_broker build_auth build_logger build_mail
+up_build: build_broker build_auth build_logger build_mail build_listener
 	@echo "Stopping docker images (if running...)"
 	docker compose down
 	@echo "Building (when required) and starting docker images..."
@@ -48,6 +49,12 @@ build_mail:
 	cd ../mail-service && env GOOS=linux CGO_ENABLED=0 go build -o ${MAIL_BINARY} ./cmd/api
 	@echo "Done!"
 
+## build_listener: builds the listener binary as a linux executable
+build_listener:
+	@echo "Building listener binary..."
+	cd ../listener-service && env GOOS=linux CGO_ENABLED=0 go build -o ${LISTENER_BINARY} .
+	@echo "Done!"
+
 ## build_front: builds the frone end binary
 build_front:
 	@echo "Building front end binary..."

project/docker-compose.yml

@@ -50,6 +50,15 @@ services:
       FROM_ADDR: me@here.com
 
 
+  listener-service:
+    build:
+      context: ./../listener-service/
+      dockerfile: ./../listener-service/listener-service.dockerfile
+    restart: always
+    deploy:
+      mode: replicated
+      replicas: 1
+
   postgres:
     image: postgres:16.4-alpine
     ports: