chore(gonf): factorise hostflag management

cmd/gonf/cmd_build.go

@@ -2,19 +2,13 @@ package main
 
 import (
 	"context"
-	"errors"
 	"flag"
 	"fmt"
 	"io"
-	"log/slog"
 	"os"
 	"os/exec"
 )
 
-var (
-	hostFlag string
-)
-
 func cmdBuild(ctx context.Context,
 	f *flag.FlagSet,
 	args []string,
@@ -23,43 +17,33 @@ func cmdBuild(ctx context.Context,
 ) error {
 	f.Init(`gonf build [-FLAG]
 where FLAG can be one or more of`, flag.ContinueOnError)
-	f.StringVar(&hostFlag, "host", "", "(REQUIRED) a valid $GONF_CONFIG/hosts/ subdirectory inside your gonf configurations repository")
+	hostFlag := addHostFlag(f)
 	f.SetOutput(stderr)
 	f.Parse(args)
 	if helpMode {
 		f.SetOutput(stdout)
 		f.Usage()
 	}
-	if hostFlag == "" {
+	hostDir, err := hostFlagToHostDir(f, hostFlag)
+	if err != nil {
 		f.Usage()
-		return errors.New("Required -host FLAG is missing")
+		return err
 	}
-	hostDir := configDir + "/hosts/" + hostFlag
-	if info, err := os.Stat(hostDir); err != nil {
-		f.Usage()
-		return fmt.Errorf("Invalid host name %s, the %s directory returned error %+v", hostFlag, hostDir, err)
-	} else if !info.IsDir() {
-		f.Usage()
-		return fmt.Errorf("Invalid host name %s, %s is not a directory", hostFlag, hostDir)
-	}
-	return runBuild(ctx, hostDir)
+	return runBuild(ctx, stderr, hostDir)
 }
 
-func runBuild(ctx context.Context, hostDir string) error {
+func runBuild(ctx context.Context, stderr io.Writer, hostDir string) error {
 	wd, err := os.Getwd()
+	if err != nil {
+		return err
+	}
 	defer os.Chdir(wd)
 	os.Chdir(hostDir)
-	if err != nil {
-		slog.Error("build", "hostDir", hostDir, "error", err)
-		return err
-	}
 	cmd := exec.CommandContext(ctx, "go", "build", "-ldflags", "-s -w -extldflags \"-static\"", hostDir)
 	cmd.Env = append(cmd.Environ(), "CGO_ENABLED=0")
-	out, err := cmd.CombinedOutput()
-	if err != nil {
-		slog.Error("build", "hostDir", hostDir, "error", err, "combinedOutput", out)
+	if out, err := cmd.CombinedOutput(); err != nil {
+		fmt.Fprint(stderr, string(out))
 		return err
 	}
-	slog.Debug("build", "hostDir", hostDir, "combinedOutput", out)
 	return nil
 }

cmd/gonf/hostflag.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+func addHostFlag(f *flag.FlagSet) *string {
+	return f.String("host", "", "(REQUIRED) a valid $GONF_CONFIG/hosts/ subdirectory")
+}
+
+func hostFlagToHostDir(f *flag.FlagSet, hostFlag *string) (string, error) {
+	if hostFlag == nil {
+		return "", errors.New("required -host FLAG is missing")
+	}
+	hostDir := filepath.Join(configDir, "hosts", *hostFlag)
+	if info, err := os.Stat(hostDir); err != nil {
+		return "", fmt.Errorf("invalid host name %s: %+v", *hostFlag, err)
+	} else if !info.IsDir() {
+		return "", fmt.Errorf("invalid host name %s: %s is not a directory", *hostFlag, hostDir)
+	}
+	return hostDir, nil
+}

cmd/gonf/main.go

@@ -25,7 +25,7 @@ func main() {
 		os.Stdout,
 		os.Stderr,
 	); err != nil {
-		fmt.Fprintf(os.Stderr, "%s\n", err)
+		fmt.Fprintf(os.Stderr, "%+v\n", err)
 		os.Exit(1)
 	}
 }