syncthing/vendor/gopkg.in/urfave/cli.v1/help.go
Jakob Borg 916ec63af6 cmd/stdiscosrv: New discovery server (fixes #4618)
This is a new revision of the discovery server. Relevant changes and
non-changes:

- Protocol towards clients is unchanged.

- Recommended large scale design is still to be deployed nehind nginx (I
  tested, and it's still a lot faster at terminating TLS).

- Database backend is leveldb again, only. It scales enough, is easy to
  setup, and we don't need any backend to take care of.

- Server supports replication. This is a simple TCP channel - protect it
  with a firewall when deploying over the internet. (We deploy this within
  the same datacenter, and with firewall.) Any incoming client announces
  are sent over the replication channel(s) to other peer discosrvs.
  Incoming replication changes are applied to the database as if they came
  from clients, but without the TLS/certificate overhead.

- Metrics are exposed using the prometheus library, when enabled.

- The database values and replication protocol is protobuf, because JSON
  was quite CPU intensive when I tried that and benchmarked it.

- The "Retry-After" value for failed lookups gets slowly increased from
  a default of 120 seconds, by 5 seconds for each failed lookup,
  independently by each discosrv. This lowers the query load over time for
  clients that are never seen. The Retry-After maxes out at 3600 after a
  couple of weeks of this increase. The number of failed lookups is
  stored in the database, now and then (avoiding making each lookup a
  database put).

All in all this means clients can be pointed towards a cluster using
just multiple A / AAAA records to gain both load sharing and redundancy
(if one is down, clients will talk to the remaining ones).

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4648
2018-01-14 08:52:31 +00:00

339 lines
8.7 KiB
Go

package cli
import (
"fmt"
"io"
"os"
"strings"
"text/tabwriter"
"text/template"
)
// AppHelpTemplate is the text template for the Default help topic.
// cli.go uses text/template to render templates. You can
// render custom help text by setting this variable.
var AppHelpTemplate = `NAME:
{{.Name}}{{if .Usage}} - {{.Usage}}{{end}}
USAGE:
{{if .UsageText}}{{.UsageText}}{{else}}{{.HelpName}} {{if .VisibleFlags}}[global options]{{end}}{{if .Commands}} command [command options]{{end}} {{if .ArgsUsage}}{{.ArgsUsage}}{{else}}[arguments...]{{end}}{{end}}{{if .Version}}{{if not .HideVersion}}
VERSION:
{{.Version}}{{end}}{{end}}{{if .Description}}
DESCRIPTION:
{{.Description}}{{end}}{{if len .Authors}}
AUTHOR{{with $length := len .Authors}}{{if ne 1 $length}}S{{end}}{{end}}:
{{range $index, $author := .Authors}}{{if $index}}
{{end}}{{$author}}{{end}}{{end}}{{if .VisibleCommands}}
COMMANDS:{{range .VisibleCategories}}{{if .Name}}
{{.Name}}:{{end}}{{range .VisibleCommands}}
{{join .Names ", "}}{{"\t"}}{{.Usage}}{{end}}{{end}}{{end}}{{if .VisibleFlags}}
GLOBAL OPTIONS:
{{range $index, $option := .VisibleFlags}}{{if $index}}
{{end}}{{$option}}{{end}}{{end}}{{if .Copyright}}
COPYRIGHT:
{{.Copyright}}{{end}}
`
// CommandHelpTemplate is the text template for the command help topic.
// cli.go uses text/template to render templates. You can
// render custom help text by setting this variable.
var CommandHelpTemplate = `NAME:
{{.HelpName}} - {{.Usage}}
USAGE:
{{if .UsageText}}{{.UsageText}}{{else}}{{.HelpName}}{{if .VisibleFlags}} [command options]{{end}} {{if .ArgsUsage}}{{.ArgsUsage}}{{else}}[arguments...]{{end}}{{end}}{{if .Category}}
CATEGORY:
{{.Category}}{{end}}{{if .Description}}
DESCRIPTION:
{{.Description}}{{end}}{{if .VisibleFlags}}
OPTIONS:
{{range .VisibleFlags}}{{.}}
{{end}}{{end}}
`
// SubcommandHelpTemplate is the text template for the subcommand help topic.
// cli.go uses text/template to render templates. You can
// render custom help text by setting this variable.
var SubcommandHelpTemplate = `NAME:
{{.HelpName}} - {{if .Description}}{{.Description}}{{else}}{{.Usage}}{{end}}
USAGE:
{{if .UsageText}}{{.UsageText}}{{else}}{{.HelpName}} command{{if .VisibleFlags}} [command options]{{end}} {{if .ArgsUsage}}{{.ArgsUsage}}{{else}}[arguments...]{{end}}{{end}}
COMMANDS:{{range .VisibleCategories}}{{if .Name}}
{{.Name}}:{{end}}{{range .VisibleCommands}}
{{join .Names ", "}}{{"\t"}}{{.Usage}}{{end}}
{{end}}{{if .VisibleFlags}}
OPTIONS:
{{range .VisibleFlags}}{{.}}
{{end}}{{end}}
`
var helpCommand = Command{
Name: "help",
Aliases: []string{"h"},
Usage: "Shows a list of commands or help for one command",
ArgsUsage: "[command]",
Action: func(c *Context) error {
args := c.Args()
if args.Present() {
return ShowCommandHelp(c, args.First())
}
ShowAppHelp(c)
return nil
},
}
var helpSubcommand = Command{
Name: "help",
Aliases: []string{"h"},
Usage: "Shows a list of commands or help for one command",
ArgsUsage: "[command]",
Action: func(c *Context) error {
args := c.Args()
if args.Present() {
return ShowCommandHelp(c, args.First())
}
return ShowSubcommandHelp(c)
},
}
// Prints help for the App or Command
type helpPrinter func(w io.Writer, templ string, data interface{})
// Prints help for the App or Command with custom template function.
type helpPrinterCustom func(w io.Writer, templ string, data interface{}, customFunc map[string]interface{})
// HelpPrinter is a function that writes the help output. If not set a default
// is used. The function signature is:
// func(w io.Writer, templ string, data interface{})
var HelpPrinter helpPrinter = printHelp
// HelpPrinterCustom is same as HelpPrinter but
// takes a custom function for template function map.
var HelpPrinterCustom helpPrinterCustom = printHelpCustom
// VersionPrinter prints the version for the App
var VersionPrinter = printVersion
// ShowAppHelpAndExit - Prints the list of subcommands for the app and exits with exit code.
func ShowAppHelpAndExit(c *Context, exitCode int) {
ShowAppHelp(c)
os.Exit(exitCode)
}
// ShowAppHelp is an action that displays the help.
func ShowAppHelp(c *Context) (err error) {
if c.App.CustomAppHelpTemplate == "" {
HelpPrinter(c.App.Writer, AppHelpTemplate, c.App)
return
}
customAppData := func() map[string]interface{} {
if c.App.ExtraInfo == nil {
return nil
}
return map[string]interface{}{
"ExtraInfo": c.App.ExtraInfo,
}
}
HelpPrinterCustom(c.App.Writer, c.App.CustomAppHelpTemplate, c.App, customAppData())
return nil
}
// DefaultAppComplete prints the list of subcommands as the default app completion method
func DefaultAppComplete(c *Context) {
for _, command := range c.App.Commands {
if command.Hidden {
continue
}
for _, name := range command.Names() {
fmt.Fprintln(c.App.Writer, name)
}
}
}
// ShowCommandHelpAndExit - exits with code after showing help
func ShowCommandHelpAndExit(c *Context, command string, code int) {
ShowCommandHelp(c, command)
os.Exit(code)
}
// ShowCommandHelp prints help for the given command
func ShowCommandHelp(ctx *Context, command string) error {
// show the subcommand help for a command with subcommands
if command == "" {
HelpPrinter(ctx.App.Writer, SubcommandHelpTemplate, ctx.App)
return nil
}
for _, c := range ctx.App.Commands {
if c.HasName(command) {
if c.CustomHelpTemplate != "" {
HelpPrinterCustom(ctx.App.Writer, c.CustomHelpTemplate, c, nil)
} else {
HelpPrinter(ctx.App.Writer, CommandHelpTemplate, c)
}
return nil
}
}
if ctx.App.CommandNotFound == nil {
return NewExitError(fmt.Sprintf("No help topic for '%v'", command), 3)
}
ctx.App.CommandNotFound(ctx, command)
return nil
}
// ShowSubcommandHelp prints help for the given subcommand
func ShowSubcommandHelp(c *Context) error {
return ShowCommandHelp(c, c.Command.Name)
}
// ShowVersion prints the version number of the App
func ShowVersion(c *Context) {
VersionPrinter(c)
}
func printVersion(c *Context) {
fmt.Fprintf(c.App.Writer, "%v version %v\n", c.App.Name, c.App.Version)
}
// ShowCompletions prints the lists of commands within a given context
func ShowCompletions(c *Context) {
a := c.App
if a != nil && a.BashComplete != nil {
a.BashComplete(c)
}
}
// ShowCommandCompletions prints the custom completions for a given command
func ShowCommandCompletions(ctx *Context, command string) {
c := ctx.App.Command(command)
if c != nil && c.BashComplete != nil {
c.BashComplete(ctx)
}
}
func printHelpCustom(out io.Writer, templ string, data interface{}, customFunc map[string]interface{}) {
funcMap := template.FuncMap{
"join": strings.Join,
}
if customFunc != nil {
for key, value := range customFunc {
funcMap[key] = value
}
}
w := tabwriter.NewWriter(out, 1, 8, 2, ' ', 0)
t := template.Must(template.New("help").Funcs(funcMap).Parse(templ))
err := t.Execute(w, data)
if err != nil {
// If the writer is closed, t.Execute will fail, and there's nothing
// we can do to recover.
if os.Getenv("CLI_TEMPLATE_ERROR_DEBUG") != "" {
fmt.Fprintf(ErrWriter, "CLI TEMPLATE ERROR: %#v\n", err)
}
return
}
w.Flush()
}
func printHelp(out io.Writer, templ string, data interface{}) {
printHelpCustom(out, templ, data, nil)
}
func checkVersion(c *Context) bool {
found := false
if VersionFlag.GetName() != "" {
eachName(VersionFlag.GetName(), func(name string) {
if c.GlobalBool(name) || c.Bool(name) {
found = true
}
})
}
return found
}
func checkHelp(c *Context) bool {
found := false
if HelpFlag.GetName() != "" {
eachName(HelpFlag.GetName(), func(name string) {
if c.GlobalBool(name) || c.Bool(name) {
found = true
}
})
}
return found
}
func checkCommandHelp(c *Context, name string) bool {
if c.Bool("h") || c.Bool("help") {
ShowCommandHelp(c, name)
return true
}
return false
}
func checkSubcommandHelp(c *Context) bool {
if c.Bool("h") || c.Bool("help") {
ShowSubcommandHelp(c)
return true
}
return false
}
func checkShellCompleteFlag(a *App, arguments []string) (bool, []string) {
if !a.EnableBashCompletion {
return false, arguments
}
pos := len(arguments) - 1
lastArg := arguments[pos]
if lastArg != "--"+BashCompletionFlag.GetName() {
return false, arguments
}
return true, arguments[:pos]
}
func checkCompletions(c *Context) bool {
if !c.shellComplete {
return false
}
if args := c.Args(); args.Present() {
name := args.First()
if cmd := c.App.Command(name); cmd != nil {
// let the command handle the completion
return false
}
}
ShowCompletions(c)
return true
}
func checkCommandCompletions(c *Context, name string) bool {
if !c.shellComplete {
return false
}
ShowCommandCompletions(c, name)
return true
}