[breaking-change] Add a health check endpoint.

Also, simplify the listen endpoint configuration format.

config.toml.example

@@ -1,10 +1,7 @@
-[pages]
-protocol = "tcp"
-address = ":3333"
-
-[caddy]
-protocol = "tcp"
-address = ":3334"
+[listen]
+pages = "tcp/:3000"
+caddy = "tcp/:3001"
+health = "tcp/:3002"
 
 [wildcard]
 domain = "codeberg.page"

src/config.go

@@ -6,19 +6,17 @@ import (
 	"github.com/pelletier/go-toml/v2"
 )
 
-type ListenConfig struct {
-	Protocol string `toml:"protocol"`
-	Address  string `toml:"address"`
-}
-
 type CacheConfig struct {
 	MaxSize uint64 `toml:"max-size"` // in bytes
 	MaxAge  string `toml:"max-age"`
 }
 
 type Config struct {
-	Pages    ListenConfig `toml:"pages"`
-	Caddy    ListenConfig `toml:"caddy"`
+	Listen struct {
+		Pages  string `toml:"pages"`
+		Caddy  string `toml:"caddy"`
+		Health string `toml:"health"`
+	} `toml:"listen"`
 	Wildcard struct {
 		Domain    string `toml:"domain"`
 		CloneURL  string `toml:"clone-url"`

src/health.go

@@ -0,0 +1,11 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+)
+
+func ServeHealth(w http.ResponseWriter, r *http.Request) {
+	w.WriteHeader(http.StatusOK)
+	fmt.Fprintln(w, "ok")
+}

src/main.go

@@ -6,12 +6,18 @@ import (
 	"net"
 	"net/http"
 	"os"
+	"strings"
 )
 
 var backend Backend
 
-func serveHandler(name string, listen ListenConfig, serve func(http.ResponseWriter, *http.Request)) {
-	listener, err := net.Listen(listen.Protocol, listen.Address)
+func serveHandler(name string, listen string, serve func(http.ResponseWriter, *http.Request)) {
+	protocol, address, ok := strings.Cut(listen, "/")
+	if !ok {
+		log.Fatalf("%s: %s: malformed endpoint", name, listen)
+	}
+
+	listener, err := net.Listen(protocol, address)
 	if err != nil {
 		log.Fatalf("%s: %s\n", name, err)
 	}
@@ -73,9 +79,15 @@ func main() {
 
 	log.Println("ready")
 
-	if config.Caddy != (ListenConfig{}) {
-		go serveHandler("caddy", config.Caddy, ServeCaddy)
+	go serveHandler("pages", config.Listen.Pages, ServePages)
+
+	if config.Listen.Caddy != "" {
+		go serveHandler("caddy", config.Listen.Caddy, ServeCaddy)
 	}
 
-	serveHandler("pages", config.Pages, ServePages)
+	if config.Listen.Health != "" {
+		go serveHandler("health", config.Listen.Health, ServeHealth)
+	}
+
+	select {}
 }