add simple web server

cmd/web_server/main.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"strconv"
+
+	"github.com/go-chi/chi"
+)
+
+func main() {
+	router := chi.NewRouter()
+
+	router.Get("/", func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte("Hello world"))
+	})
+
+	var port int
+    var err error
+	port_str, exists := os.LookupEnv("WEB_SERVER_PORT")
+	if exists {
+        port, err = strconv.Atoi(port_str)
+		if err != nil {
+			log.Fatal("env:MAIL_SERVER_PORT is not a number")
+		}
+	} else {
+		port = 3000
+	}
+
+    log.Println("Listening on port", port)
+    http.ListenAndServe(fmt.Sprintf(":%d", port), router)
+}

go.mod

@@ -5,5 +5,6 @@ go 1.21.6
 require (
 	github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21 // indirect
 	github.com/emersion/go-smtp v0.20.2 // indirect
+	github.com/go-chi/chi v1.5.5 // indirect
 	github.com/mattn/go-sqlite3 v1.14.22 // indirect
 )

go.sum

@@ -2,5 +2,7 @@ github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21 h1:OJyUGMJTzHTd1X
 github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21/go.mod h1:iL2twTeMvZnrg54ZoPDNfJaJaqy0xIQFuBdrLsmspwQ=
 github.com/emersion/go-smtp v0.20.2 h1:peX42Qnh5Q0q3vrAnRy43R/JwTnnv75AebxbkTL7Ia4=
 github.com/emersion/go-smtp v0.20.2/go.mod h1:qm27SGYgoIPRot6ubfQ/GpiPy/g3PaZAVRxiO/sDUgQ=
+github.com/go-chi/chi v1.5.5 h1:vOB/HbEMt9QqBqErz07QehcOKHaWFtuj87tTDVz2qXE=
+github.com/go-chi/chi v1.5.5/go.mod h1:C9JqLr3tIYjDOZpzn+BCuxY8z8vmca43EeMgyZt7irw=
 github.com/mattn/go-sqlite3 v1.14.22 h1:2gZY6PC6kBnID23Tichd1K+Z0oS6nE/XwU+Vz/5o4kU=
 github.com/mattn/go-sqlite3 v1.14.22/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=