func run()

in tools/mount_gcsfuse/main.go [223:298]
51 lines of code
11 McCabe index (conditional complexity)

func run(args []string) (err error) {
	// If invoked with a single "--help" argument, print a usage message and exit
	// successfully.
	if len(args) == 2 && args[1] == "--help" {
		fmt.Fprintf(
			os.Stderr,
			"Usage: %s [-o options] bucket_name mount_point\n",
			args[0])

		return
	}

	// Find the path to gcsfuse.
	gcsfusePath, err := findGcsfuse()
	if err != nil {
		err = fmt.Errorf("findGcsfuse: %w", err)
		return
	}

	// Find the path to fusermount.
	fusermountPath, err := findFusermount()
	if err != nil {
		err = fmt.Errorf("findFusermount: %w", err)
		return
	}

	// Attempt to parse arguments.
	device, mountPoint, opts, err := parseArgs(args)
	if err != nil {
		err = fmt.Errorf("parseArgs: %w", err)
		return
	}

	// Choose gcsfuse args.
	gcsfuseArgs, err := makeGcsfuseArgs(device, mountPoint, opts)
	if err != nil {
		err = fmt.Errorf("makeGcsfuseArgs: %w", err)
		return
	}

	fmt.Fprintf(
		os.Stderr,
		"Calling gcsfuse with arguments: %s\n",
		strings.Join(gcsfuseArgs, " "))

	// Run gcsfuse.
	cmd := exec.Command(gcsfusePath, gcsfuseArgs...)
	cmd.Env = append(cmd.Env, fmt.Sprintf("PATH=%s", path.Dir(fusermountPath)))

	// Pass through the https_proxy/http_proxy environment variable,
	// in case the host requires a proxy server to reach the GCS endpoint.
	// http_proxy has precedence over http_proxy, in case both are set
	if p, ok := os.LookupEnv("https_proxy"); ok {
		cmd.Env = append(cmd.Env, fmt.Sprintf("https_proxy=%s", p))
	} else if p, ok := os.LookupEnv("http_proxy"); ok {
		cmd.Env = append(cmd.Env, fmt.Sprintf("http_proxy=%s", p))
	}
	// Pass through the no_proxy enviroment variable. Whenever
	// using the http(s)_proxy environment variables. This should
	// also be included to know for which hosts the use of proxies
	// should be ignored.
	if p, ok := os.LookupEnv("no_proxy"); ok {
		cmd.Env = append(cmd.Env, fmt.Sprintf("no_proxy=%s", p))
	}

	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr

	err = cmd.Run()
	if err != nil {
		err = fmt.Errorf("running gcsfuse: %w", err)
		return
	}

	return
}