feat: move cmd to own dir

.gitignore

@@ -1 +1,2 @@
 cache.json
+dist/*

.goreleaser.yml

@@ -1,6 +1,7 @@
 project_name: "glucose_exporter"
 builds:
-  - env:
+  - main: ./cmd/glucose_exporter/
+    env:
       - CGO_ENABLED=0
     goos:
       - linux
@@ -10,9 +11,9 @@ builds:
       - "-s"
       - "-w"
       - "-extldflags '-static'"
-      - "-X git.wobcom.de/smartmetering/kerouac/cmd.version={{.Version}}"
+      - "-X main.version={{.Version}}"
-      - "-X git.wobcom.de/smartmetering/kerouac/cmd.commit={{.ShortCommit}}"
+      - "-X main.commit={{.ShortCommit}}"
-      - "-X git.wobcom.de/smartmetering/kerouac/cmd.date={{.Date}}"
+      - "-X main.date={{.Date}}"
 checksum:
   name_template: "checksums.txt"
 snapshot:

Earthfile

@@ -1,5 +1,5 @@
 VERSION 0.7
-ARG --global GO_VERSION=1.22.0
+ARG --global GO_VERSION=1.22.1
 ARG --global GOLANGCILINT_VERSION=v1.54.2
 ARG --global GORELEASER_VERSION=v1.24.0
 FROM golang:$GO_VERSION-alpine3.18
@@ -10,12 +10,14 @@ SAVE_CODE:
 	SAVE ARTIFACT go.mod AS LOCAL go.mod
 	SAVE ARTIFACT go.sum AS LOCAL go.sum
 	SAVE ARTIFACT api AS LOCAL api
+	SAVE ARTIFACT cmd AS LOCAL cmd
 	SAVE ARTIFACT httpslog AS LOCAL httpslog
 	SAVE ARTIFACT internal AS LOCAL internal
 
 code:
 	COPY go.mod go.sum ./
 	COPY --dir api ./
+	COPY --dir cmd ./
 	COPY --dir httpslog ./
 	COPY --dir internal ./
 	COPY --dir vendor ./
@@ -71,8 +73,17 @@ goreleaser:
 	RUN goreleaser $CMD
 	SAVE ARTIFACT dist dist
 
+ssl-certs:
+  RUN set -ex \
+    && apk add --no-cache ca-certificates
+  SAVE ARTIFACT /etc/ssl/certs/ca-certificates.crt ca-certificates.crt
+
 docker:
 	FROM scratch
 	ARG DOCKER_TAG
-	COPY +goreleaser/dist/glucose_exporter_linux_amd64_v1/glucose_exporter /bin/glucose_exporter
+  	COPY +ssl-certs/ca-certificates.crt /etc/ssl/certs/ca-certificates.crt
+	COPY +goreleaser/dist/glucose_exporter_linux_amd64_v1/glucose_exporter /glucose_exporter
+	VOLUME /var/cache/glucose_exporter
+  	ENTRYPOINT ["/glucose_exporter"]
+	CMD ["serve"]
 	SAVE IMAGE --push ghcr.io/xsteadfastx/glucose_exporter:$DOCKER_TAG

cmd/glucose_exporter/main.go

@@ -1,7 +1,10 @@
+//nolint:forbidigo,gochecknoglobals
 package main
 
 import (
 	"errors"
+	"flag"
+	"fmt"
 	"log/slog"
 	"net/http"
 	"os"
@@ -9,19 +12,58 @@ import (
 
 	"github.com/caarlos0/env/v10"
 	"github.com/lmittmann/tint"
-
 	"go.xsfx.dev/glucose_exporter/httpslog"
 	"go.xsfx.dev/glucose_exporter/internal/cache"
 	"go.xsfx.dev/glucose_exporter/internal/config"
 	"go.xsfx.dev/glucose_exporter/internal/metrics"
 )
 
-const addr = ":2112"
+var (
+	version = "dev"
+	commit  = "none"
+	date    = "unknown"
+)
+
+const help = "expected 'serve' or 'version' subcommands"
 
 func main() {
 	logOpts := &tint.Options{Level: slog.LevelInfo, TimeFormat: time.Kitchen}
 	initLogging(logOpts)
 
+	if len(os.Args) < 2 {
+		slog.Error(help)
+		os.Exit(1)
+	}
+
+	switch os.Args[1] {
+	case "serve":
+		flags := flag.NewFlagSet("serve", flag.ExitOnError)
+
+		addr := flags.String("addr", ":2112", "address to listen")
+		flags.BoolFunc("help", "print help", func(_ string) error {
+			flags.PrintDefaults()
+			os.Exit(0)
+
+			return nil
+		})
+
+		if err := flags.Parse(os.Args[2:]); err != nil {
+			slog.Error("parsing flags", "err", err)
+			os.Exit(0)
+		}
+
+		serveCmd(*addr)
+
+	case "version":
+		versionCmd()
+
+	default:
+		slog.Error(help)
+		os.Exit(1)
+	}
+}
+
+func serveCmd(addr string) {
 	if err := env.Parse(&config.Cfg); err != nil {
 		slog.Error("parsing env config", "err", err)
 		os.Exit(1)
@@ -40,9 +82,9 @@ func main() {
 			if err := os.WriteFile(cache.FullPath(), []byte("{}"), 0o600); err != nil {
 				cacheFileLogger.Error("init cache file", "err", err)
 				os.Exit(1)
-			} else {
-				cacheFileLogger.Debug("init cache file")
 			}
+
+			cacheFileLogger.Debug("init cache file")
 		} else {
 			cacheFileLogger.Error("getting cache file stat", "err", err)
 			os.Exit(1)
@@ -54,12 +96,23 @@ func main() {
 
 	slog.Info("listening", "addr", addr)
 
-	if err := http.ListenAndServe(addr, httpslog.Handler()(mux)); err != nil {
+	server := &http.Server{
+		Addr:              addr,
+		ReadTimeout:       time.Second,
+		ReadHeaderTimeout: time.Second,
+		Handler:           httpslog.Handler()(mux),
+	}
+
+	if err := server.ListenAndServe(); err != nil {
 		slog.Error("listen and serve", "err", err)
 		os.Exit(1)
 	}
 }
 
+func versionCmd() {
+	fmt.Printf("glucose_exporter %s, commit %s, %s\n", version, commit, date)
+}
+
 func initLogging(opts *tint.Options) {
 	slog.SetDefault(slog.New(tint.NewHandler(os.Stderr, opts)))
 }