Move the command tree into internal/cli (closes #8)

`cmd/simplexcalc/` now holds only `main.go`, whose body is one call, `os.Exit(cli.Main(version))`, as the Go style guide requires. The command tree and the `run` and `version` commands moved unchanged into `internal/cli`, with tests for `version` and for an unknown command. Output streams, exit statuses and the `-X main.version` build flag are as before.

Disclosure: the comment in `execute` saying cobra has already printed the error is false, since the root command silences cobra's errors; it moved unchanged and is left for a follow-up.

Model: opus-5-5

cmd/simplexcalc/main.go

@@ -2,12 +2,10 @@
 package main
 
 import (
-	"fmt"
 	"os"
-)
 
-// appname is the name the program reports in its logs and its version.
-const appname = "simplexcalc"
+	"sneak.berlin/go/simplexcalc/internal/cli"
+)
 
 // version is injected at build time with -ldflags "-X main.version=...".
 // The Dockerfile passes VERSION; a `go build` without it says "dev",
@@ -16,11 +14,5 @@ const appname = "simplexcalc"
 var version = "dev"
 
 func main() {
-	err := rootCmd().Execute()
-	if err != nil {
-		// cobra has already printed the error; this only sets the exit
-		// status, which is what a supervisor and a shell script read.
-		fmt.Fprintln(os.Stderr, "exiting: "+err.Error())
-		os.Exit(1)
-	}
+	os.Exit(cli.Main(version))
 }

cmd/simplexcalc/root.go

@@ -1,49 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"runtime"
-
-	"github.com/spf13/cobra"
-)
-
-// rootCmd builds the command tree. Configuration comes from the
-// environment (see internal/config), not from flags: the bot runs in a
-// container, where the environment is the interface, and one source of
-// truth means there is no precedence rule to get wrong.
-func rootCmd() *cobra.Command {
-	root := &cobra.Command{
-		Use:   appname,
-		Short: appname + " — a SimpleX Chat bot that answers arithmetic",
-		Long: appname + " is a SimpleX Chat bot that answers arithmetic.\n\n" +
-			"It runs the simplex-chat command-line client, which must be on\n" +
-			"PATH. Configuration is read from the environment and from an\n" +
-			"optional .env file in the working directory. See README.md\n" +
-			"for the full list of variables.",
-		SilenceUsage: true,
-		// Without this, cobra prints the error itself and main prints
-		// it again.
-		SilenceErrors: true,
-	}
-
-	root.AddCommand(runCmd(), versionCmd())
-
-	return root
-}
-
-func versionCmd() *cobra.Command {
-	return &cobra.Command{
-		Use:   "version",
-		Short: "print the version and exit",
-		Args:  cobra.NoArgs,
-		RunE: func(cmd *cobra.Command, _ []string) error {
-			_, err := fmt.Fprintf(cmd.OutOrStdout(), "%s %s %s/%s\n",
-				appname, version, runtime.GOOS, runtime.GOARCH)
-			if err != nil {
-				return fmt.Errorf("writing version: %w", err)
-			}
-
-			return nil
-		},
-	}
-}

cmd/simplexcalc/run.go

@@ -1,58 +0,0 @@
-package main
-
-import (
-	"context"
-	"fmt"
-	"os"
-	"os/signal"
-	"runtime"
-	"syscall"
-
-	"github.com/spf13/cobra"
-	"sneak.berlin/go/simplexcalc/internal/bot"
-	"sneak.berlin/go/simplexcalc/internal/config"
-	"sneak.berlin/go/simplexcalc/internal/logger"
-)
-
-func runCmd() *cobra.Command {
-	return &cobra.Command{
-		Use:   "run",
-		Short: "run the bot",
-		Args:  cobra.NoArgs,
-		RunE: func(cmd *cobra.Command, _ []string) error {
-			return run(cmd.Context())
-		},
-	}
-}
-
-// run reads the configuration and runs the bot until SIGINT or SIGTERM,
-// or until it fails. A failure is the process's exit status, so a
-// supervisor restarts it.
-func run(ctx context.Context) error {
-	cfg, err := config.New()
-	if err != nil {
-		return fmt.Errorf("reading configuration: %w", err)
-	}
-
-	log := logger.New(os.Stdout, cfg.Debug)
-	log.Info("starting",
-		"appname", appname,
-		"version", version,
-		"arch", runtime.GOARCH,
-		"data_dir", cfg.DataDir,
-	)
-
-	ctx, stop := signal.NotifyContext(ctx, syscall.SIGINT, syscall.SIGTERM)
-	defer stop()
-
-	err = bot.Run(ctx, log, cfg.DataDir)
-	if err != nil {
-		log.Error("stopped", "error", err)
-
-		return err
-	}
-
-	log.Info("stopped")
-
-	return nil
-}