fix: remove internal package and move it to cmd (#321)

cmd/gotenberg.go

@@ -0,0 +1,119 @@
+package gotenbergcmd
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/signal"
+	"time"
+
+	"github.com/gotenberg/gotenberg/v7/pkg/gotenberg"
+	flag "github.com/spf13/pflag"
+)
+
+// See https://patorjk.com/software/taag/#p=display&f=Small%20Slant&t=Gotenberg.
+// Credits: https://github.com/labstack/echo/blob/v4.3.0/echo.go#L240.
+const banner = `
+  _____     __           __               
+ / ___/__  / /____ ___  / /  ___ _______ _
+/ (_ / _ \/ __/ -_) _ \/ _ \/ -_) __/ _ '/
+\___/\___/\__/\__/_//_/_.__/\__/_/  \_, / 
+                                   /___/
+
+A Docker-powered stateless API for PDF files.
+Version: %s
+-------------------------------------------------------
+`
+
+// Version is the... version of the Gotenberg application. We set it at the
+// build stage of the Docker image.
+var Version = "snapshot"
+
+// Run starts the Gotenberg application. Call this in the main of your program.
+func Run() {
+	fmt.Printf(banner, Version)
+
+	// Creates the roo` FlagSet and adds the modules flags to it.
+	fs := flag.NewFlagSet("gotenberg", flag.ExitOnError)
+	fs.Duration("gotenberg-graceful-shutdown-duration", time.Duration(30)*time.Second, "Set the graceful shutdown duration")
+
+	descriptors := gotenberg.GetModuleDescriptors()
+	var modsInfo string
+	for _, desc := range descriptors {
+		fs.AddFlagSet(desc.FlagSet)
+		modsInfo += desc.ID + " "
+	}
+
+	fmt.Printf("[SYSTEM] modules: %s\n", modsInfo)
+
+	// Parses the flags...
+	err := fs.Parse(os.Args[1:])
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+
+	// ...and creates a wrapper around those.
+	parsedFlags := gotenberg.ParsedFlags{FlagSet: fs}
+
+	// Get the graceful shutdown duration.
+	gracefulShutdownDuration := parsedFlags.MustDuration("gotenberg-graceful-shutdown-duration")
+
+	ctx := gotenberg.NewContext(parsedFlags, descriptors)
+
+	// Starts application modules.
+	apps, err := ctx.Modules(new(gotenberg.App))
+	if err != nil {
+		fmt.Printf("[FATAL] %s\n", err)
+		os.Exit(1)
+	}
+
+	for _, a := range apps {
+		go func(app gotenberg.App) {
+			id := app.(gotenberg.Module).Descriptor().ID
+			err = app.Start()
+
+			if err != nil {
+				fmt.Printf("[FATAL] starting %s: %s\n", id, err)
+				os.Exit(1)
+			}
+
+			startupMessage := app.StartupMessage()
+			if startupMessage == "" {
+				fmt.Printf("[SYSTEM] %s: application started\n", id)
+
+				return
+			}
+
+			fmt.Printf("[SYSTEM] %s: %s\n", id, startupMessage)
+		}(a.(gotenberg.App))
+
+	}
+
+	quit := make(chan os.Signal, 1)
+
+	// We'll accept graceful shutdowns when quit via SIGINT (Ctrl+C).
+	signal.Notify(quit, os.Interrupt)
+
+	// Block until we receive our signal.
+	<-quit
+
+	gracefulShutdownCtx, cancel := context.WithTimeout(context.Background(), gracefulShutdownDuration)
+	defer cancel()
+
+	fmt.Printf("[SYSTEM] graceful shutdown of %s\n", gracefulShutdownDuration)
+
+	for _, a := range apps {
+		id := a.(gotenberg.Module).Descriptor().ID
+		app := a.(gotenberg.App)
+
+		err = app.Stop(gracefulShutdownCtx)
+		if err != nil {
+			fmt.Printf("[ERROR] stopping %s: %s\n", id, err)
+		}
+
+		fmt.Printf("[SYSTEM] %s: application stopped\n", id)
+	}
+
+	os.Exit(0)
+}