Golang Context.Stdout方法代码示例

// Function retries the given function for the given number of
// attempts at the given interval.
func Function(ctx *tool.Context, fn func() error, opts ...RetryOpt) error {
	attempts, interval := defaultAttempts, defaultInterval
	for _, opt := range opts {
		switch typedOpt := opt.(type) {
		case AttemptsOpt:
			attempts = int(typedOpt)
		case IntervalOpt:
			interval = time.Duration(typedOpt)
		}
	}

	var err error
	for i := 1; i <= attempts; i++ {
		if i > 1 {
			fmt.Fprintf(ctx.Stdout(), "Attempt %d/%d:\n", i, attempts)
		}
		if err = fn(); err == nil {
			return nil
		}
		fmt.Fprintf(ctx.Stderr(), "%v\n", err)
		if i < attempts {
			fmt.Fprintf(ctx.Stdout(), "Wait for %v before next attempt...\n", interval)
			time.Sleep(interval)
		}
	}
	return fmt.Errorf("Failed %d times in a row. Last error:\n%v", attempts, err)
}

// RunCommand runs the specified command with the specified args and environment
// whilst logging the output to ctx.Stdout() on error or if tracing is requested
// via the -v flag.
func RunCommand(ctx *tool.Context, env map[string]string, bin string, args ...string) error {
	var out bytes.Buffer
	opts := ctx.Run().Opts()
	opts.Stdout = &out
	opts.Stderr = &out
	opts.Env = env
	err := ctx.Run().CommandWithOpts(opts, bin, args...)
	if err != nil || tool.VerboseFlag {
		fmt.Fprintf(ctx.Stdout(), "%s", out.String())
	}
	return err
}

// WARNING: this function is in the proces of being removed and replaced
// by the profiles based configuration (see jiri/profiles). Use
// profiles.ConfigHelper instead of this for new code.
//
// JiriLegacyEnvironment returns the environment variables setting for the project.
// The util package captures the original state of the relevant environment
// variables when the tool is initialized and every invocation of this function
// updates this original state according to the jiri tool configuration.
//
// By default, the Go and VDL workspaces are added to the GOPATH and VDLPATH
// environment variables respectively. In addition, the JIRI_PROFILE
// environment variable can be used to activate an environment variable setting
// for various development profiles of the project (e.g. arm, android, java, or
// nacl).  Unlike the default setting, the setting enabled by the JIRI_PROFILE
// environment variable can override existing environment.
func JiriLegacyEnvironment(ctx *tool.Context) (*envvar.Vars, error) {
	env := envvar.VarsFromOS()
	root, err := project.JiriRoot()
	if err != nil {
		return nil, err
	}
	config, err := LoadConfig(ctx)
	if err != nil {
		return nil, err
	}
	env.Set("CGO_ENABLED", "1")
	if err := setGoPath(ctx, env, root, config); err != nil {
		return nil, err
	}
	if err := setVdlPath(ctx, env, root, config); err != nil {
		return nil, err
	}
	if profile := os.Getenv(jiriProfileEnv); profile != "" {
		fmt.Fprintf(ctx.Stdout(), `NOTE: Enabling environment variable setting for %q.
This can override values of existing environment variables.
`, profile)
		switch profile {
		case "android":
			// Cross-compilation for android on linux.
			if err := setAndroidEnv(ctx, env, root); err != nil {
				return nil, err
			}
		case "arm":
			// Cross-compilation for arm on linux.
			if err := setArmEnv(ctx, env, root); err != nil {
				return nil, err
			}
		case "java":
			// Building of a Go shared library for Java.
			if err := setJavaEnv(ctx, env, root); err != nil {
				return nil, err
			}
		case "nacl":
			// Cross-compilation for nacl.
			if err := setNaclEnv(ctx, env, root); err != nil {
				return nil, err
			}
		default:
			fmt.Fprintf(ctx.Stderr(), "Unknown environment profile %q", profile)
		}
	}
	if err := setSyncbaseEnv(ctx, env, root); err != nil {
		return nil, err
	}
	return env, nil
}

func brewList(ctx *tool.Context) (map[string]bool, error) {
	var out bytes.Buffer
	opts := ctx.Run().Opts()
	opts.Stdout = &out
	opts.Stderr = &out
	err := ctx.Run().CommandWithOpts(opts, "brew", "list")
	if err != nil || tool.VerboseFlag {
		fmt.Fprintf(ctx.Stdout(), "%s", out.String())
	}
	scanner := bufio.NewScanner(&out)
	pkgs := map[string]bool{}
	for scanner.Scan() {
		pkgs[scanner.Text()] = true
	}
	return pkgs, err
}

// EnsureProfileTargetIsUninstalled ensures that the requested profile and target
// are no longer installed.
func EnsureProfileTargetIsUninstalled(ctx *tool.Context, profile string, target Target, root string) error {
	if LookupProfileTarget(profile, target) != nil {
		if ctx.Run().Opts().Verbose {
			fmt.Fprintf(ctx.Stdout(), "%v is not installed: %v", profile, target)
		}
		return nil
	}
	mgr := LookupManager(profile)
	if mgr == nil {
		return fmt.Errorf("profile %v is not supported", profile)
	}
	mgr.SetRoot(root)
	if ctx.Run().Opts().Verbose || ctx.Run().Opts().DryRun {
		fmt.Fprintf(ctx.Stdout(), "uninstall %s %s\n", profile, target.DebugString())
	}
	if err := mgr.Uninstall(ctx, target); err != nil {
		return err
	}
	return nil
}

func logResult(ctx *tool.Context, action string, mgr profiles.Manager, target profiles.Target, err error) {
	fmt.Fprintf(ctx.Stdout(), "%s: %s %s: ", action, mgr.Name(), target)
	if err == nil {
		fmt.Fprintf(ctx.Stdout(), "success\n")
	} else {
		fmt.Fprintf(ctx.Stdout(), "%v\n", err)
	}
}

// InstallPackages identifies the packages that need to be installed
// and installs them using the OS-specific package manager.
func InstallPackages(ctx *tool.Context, pkgs []string) error {
	installDepsFn := func() error {
		switch runtime.GOOS {
		case "linux":
			installPkgs := []string{}
			for _, pkg := range pkgs {
				if err := RunCommand(ctx, nil, "dpkg", "-L", pkg); err != nil {
					installPkgs = append(installPkgs, pkg)
				}
			}
			if len(installPkgs) > 0 {
				args := append([]string{"apt-get", "install", "-y"}, installPkgs...)
				fmt.Fprintf(ctx.Stdout(), "Running: sudo %s: ", strings.Join(args, " "))
				if err := RunCommand(ctx, nil, "sudo", args...); err != nil {
					fmt.Fprintf(ctx.Stdout(), "%v\n", err)
					return err
				}
				fmt.Fprintf(ctx.Stdout(), "success\n")
			}
		case "darwin":
			installPkgs := []string{}
			installedPkgs, err := brewList(ctx)
			if err != nil {
				return err
			}
			for _, pkg := range pkgs {
				if !installedPkgs[pkg] {
					installPkgs = append(installPkgs, pkg)
				}
			}
			if len(installPkgs) > 0 {
				args := append([]string{"install"}, installPkgs...)
				fmt.Fprintf(ctx.Stdout(), "Running: brew %s: ", strings.Join(args, " "))
				if err := RunCommand(ctx, nil, "brew", args...); err != nil {
					fmt.Fprintf(ctx.Stdout(), "%v\n", err)
					return err
				}
				fmt.Fprintf(ctx.Stdout(), "success\n")
			}
		}
		return nil
	}
	return ctx.Run().Function(installDepsFn, "Install dependencies")
}