feat(containers): add sse example

containers/sse/Dockerfile

@@ -0,0 +1,25 @@
+FROM golang:1.22-alpine3.19 AS build
+
+# Install git, this used to fetch VCS information when building the application
+RUN apk add --no-cache git
+
+WORKDIR /app
+
+COPY go.mod go.sum ./
+RUN go mod download
+
+COPY . .
+
+RUN CGO_ENABLED=0 GOOS=linux go build ./cmd/sse
+
+FROM alpine:3.19
+
+WORKDIR /
+
+COPY ./www /www
+
+COPY --from=build /app/sse .
+
+EXPOSE 8080
+
+CMD ["/sse"]

containers/sse/README.md

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+# Server Side Events with Serverless Containers
+
+This is a simple example of how to use Server Side Events with Scaleway Serverless Containers.
+
+## Deploying
+
+You can deploy the application using the Scaleway CLI.
+
+```console
+scw container deploy                                          
+```
+
+## Reference
+
+- <https://echo.labstack.com/docs/cookbook/sse>

containers/sse/cmd/sse/main.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"errors"
+	"log"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/labstack/echo/v4"
+	"github.com/labstack/echo/v4/middleware"
+	"github.com/r3labs/sse/v2"
+)
+
+var (
+	// Serverless Containers will scale to multiple instances.
+	// This is a way to identify which instance is sending the message to identify the source.
+	hostName, _ = os.Hostname()
+)
+
+func main() {
+	e := echo.New()
+
+	server := sse.New()             // create SSE broadcaster server
+	server.AutoReplay = false       // do not replay messages for each new subscriber that connects
+	_ = server.CreateStream("time") // EventSource in "index.html" connecting to stream named "time"
+
+	go func(s *sse.Server) {
+		ticker := time.NewTicker(1 * time.Second)
+		defer ticker.Stop()
+
+		for {
+			select {
+			case <-ticker.C:
+				s.Publish("time", &sse.Event{
+					Data: []byte("time: " + time.Now().Format(time.RFC3339Nano) + " from: " + hostName),
+				})
+			}
+		}
+	}(server)
+
+	e.Use(middleware.Logger())
+	e.Use(middleware.Recover())
+	e.Static("/", "www")
+
+	e.GET("/sse", func(c echo.Context) error { // longer variant with disconnect logic
+		log.Printf("The client is connected: %v\n", c.RealIP())
+		go func() {
+			<-c.Request().Context().Done() // Received Browser Disconnection
+			log.Printf("The client is disconnected: %v\n", c.RealIP())
+		}()
+
+		server.ServeHTTP(c.Response(), c.Request())
+
+		return nil
+	})
+
+	if err := e.Start(":8080"); err != nil && !errors.Is(err, http.ErrServerClosed) {
+		log.Fatal(err)
+	}
+}

containers/sse/go.mod

@@ -0,0 +1,22 @@
+module ssetest
+
+go 1.22.1
+
+require github.com/labstack/echo/v4 v4.12.0
+
+require gopkg.in/cenkalti/backoff.v1 v1.1.0 // indirect
+
+require (
+	github.com/golang-jwt/jwt v3.2.2+incompatible // indirect
+	github.com/labstack/gommon v0.4.2 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/r3labs/sse/v2 v2.10.0
+	github.com/valyala/bytebufferpool v1.0.0 // indirect
+	github.com/valyala/fasttemplate v1.2.2 // indirect
+	golang.org/x/crypto v0.22.0 // indirect
+	golang.org/x/net v0.24.0 // indirect
+	golang.org/x/sys v0.19.0 // indirect
+	golang.org/x/text v0.14.0 // indirect
+	golang.org/x/time v0.5.0 // indirect
+)

containers/sse/go.sum

@@ -0,0 +1,41 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/golang-jwt/jwt v3.2.2+incompatible h1:IfV12K8xAKAnZqdXVzCZ+TOjboZ2keLg81eXfW3O+oY=
+github.com/golang-jwt/jwt v3.2.2+incompatible/go.mod h1:8pz2t5EyA70fFQQSrl6XZXzqecmYZeUEB8OUGHkxJ+I=
+github.com/labstack/echo/v4 v4.12.0 h1:IKpw49IMryVB2p1a4dzwlhP1O2Tf2E0Ir/450lH+kI0=
+github.com/labstack/echo/v4 v4.12.0/go.mod h1:UP9Cr2DJXbOK3Kr9ONYzNowSh7HP0aG0ShAyycHSJvM=
+github.com/labstack/gommon v0.4.2 h1:F8qTUNXgG1+6WQmqoUWnz8WiEU60mXVVw0P4ht1WRA0=
+github.com/labstack/gommon v0.4.2/go.mod h1:QlUFxVM+SNXhDL/Z7YhocGIBYOiwB0mXm1+1bAPHPyU=
+github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
+github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
+github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/r3labs/sse/v2 v2.10.0 h1:hFEkLLFY4LDifoHdiCN/LlGBAdVJYsANaLqNYa1l/v0=
+github.com/r3labs/sse/v2 v2.10.0/go.mod h1:Igau6Whc+F17QUgML1fYe1VPZzTV6EMCnYktEmkNJ7I=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=
+github.com/valyala/bytebufferpool v1.0.0/go.mod h1:6bBcMArwyJ5K/AmCkWv1jt77kVWyCJ6HpOuEn7z0Csc=
+github.com/valyala/fasttemplate v1.2.2 h1:lxLXG0uE3Qnshl9QyaK6XJxMXlQZELvChBOCmQD0Loo=
+github.com/valyala/fasttemplate v1.2.2/go.mod h1:KHLXt3tVN2HBp8eijSv/kGJopbvo7S+qRAEEKiv+SiQ=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.22.0 h1:g1v0xeRhjcugydODzvb3mEM9SQ0HGp9s/nh3COQ/C30=
+golang.org/x/crypto v0.22.0/go.mod h1:vr6Su+7cTlO45qkww3VDJlzDn0ctJvRgYbC2NvXHt+M=
+golang.org/x/net v0.0.0-20191116160921-f9c825593386/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.24.0 h1:1PcaxkF854Fu3+lvBIx5SYn9wRlBzzcnHZSiaFFAb0w=
+golang.org/x/net v0.24.0/go.mod h1:2Q7sJY5mzlzWjKtYUEXSlBWCdyaioyXzRB2RtU8KVE8=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.19.0 h1:q5f1RH2jigJ1MoAWp2KTp3gm5zAGFUTarQZ5U386+4o=
+golang.org/x/sys v0.19.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
+golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
+golang.org/x/time v0.5.0 h1:o7cqy6amK/52YcAKIPlM3a+Fpj35zvRj2TP+e1xFSfk=
+golang.org/x/time v0.5.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
+gopkg.in/cenkalti/backoff.v1 v1.1.0 h1:Arh75ttbsvlpVA7WtVpH4u9h6Zl46xuptxqLxPiSo4Y=
+gopkg.in/cenkalti/backoff.v1 v1.1.0/go.mod h1:J6Vskwqd+OMVJl8C33mmtxTBs2gyzfv7UDAkHu8BrjI=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

containers/sse/www/index.html

@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<html>
+
+<body>
+
+    <h1>Getting server-sent updates</h1>
+    <div id="result"></div>
+
+    <script>
+        // Example taken from: https://www.w3schools.com/html/html5_serversentevents.asp
+        if (typeof (EventSource) !== "undefined") {
+            const source = new EventSource("/sse?stream=time");
+            source.onmessage = function (event) {
+                document.getElementById("result").innerHTML += event.data + "<br>";
+            };
+        } else {
+            document.getElementById("result").innerHTML = "Sorry, your browser does not support server-sent events...";
+        }
+    </script>
+
+</body>
+
+</html>