455 lines
12 KiB
Go
455 lines
12 KiB
Go
|
package cli
|
||
|
|
|
||
|
|
import (
|
||
|
|
"fmt"
|
||
|
|
"io"
|
||
|
|
"os"
|
||
|
|
"regexp"
|
||
|
|
"sort"
|
||
|
|
"strings"
|
||
|
|
"sync"
|
||
|
|
"text/template"
|
||
|
|
|
||
|
|
"github.com/armon/go-radix"
|
||
|
|
)
|
||
|
|
|
||
|
|
// CLI contains the state necessary to run subcommands and parse the
|
||
|
|
// command line arguments.
|
||
|
|
//
|
||
|
|
// CLI also supports nested subcommands, such as "cli foo bar". To use
|
||
|
|
// nested subcommands, the key in the Commands mapping below contains the
|
||
|
|
// full subcommand. In this example, it would be "foo bar".
|
||
|
|
//
|
||
|
|
// If you use a CLI with nested subcommands, some semantics change due to
|
||
|
|
// ambiguities:
|
||
|
|
//
|
||
|
|
// * We use longest prefix matching to find a matching subcommand. This
|
||
|
|
// means if you register "foo bar" and the user executes "cli foo qux",
|
||
|
|
// the "foo" commmand will be executed with the arg "qux". It is up to
|
||
|
|
// you to handle these args. One option is to just return the special
|
||
|
|
// help return code `RunResultHelp` to display help and exit.
|
||
|
|
//
|
||
|
|
// * The help flag "-h" or "-help" will look at all args to determine
|
||
|
|
// the help function. For example: "otto apps list -h" will show the
|
||
|
|
// help for "apps list" but "otto apps -h" will show it for "apps".
|
||
|
|
// In the normal CLI, only the first subcommand is used.
|
||
|
|
//
|
||
|
|
// * The help flag will list any subcommands that a command takes
|
||
|
|
// as well as the command's help itself. If there are no subcommands,
|
||
|
|
// it will note this. If the CLI itself has no subcommands, this entire
|
||
|
|
// section is omitted.
|
||
|
|
//
|
||
|
|
// * Any parent commands that don't exist are automatically created as
|
||
|
|
// no-op commands that just show help for other subcommands. For example,
|
||
|
|
// if you only register "foo bar", then "foo" is automatically created.
|
||
|
|
//
|
||
|
|
type CLI struct {
|
||
|
|
// Args is the list of command-line arguments received excluding
|
||
|
|
// the name of the app. For example, if the command "./cli foo bar"
|
||
|
|
// was invoked, then Args should be []string{"foo", "bar"}.
|
||
|
|
Args []string
|
||
|
|
|
||
|
|
// Commands is a mapping of subcommand names to a factory function
|
||
|
|
// for creating that Command implementation. If there is a command
|
||
|
|
// with a blank string "", then it will be used as the default command
|
||
|
|
// if no subcommand is specified.
|
||
|
|
//
|
||
|
|
// If the key has a space in it, this will create a nested subcommand.
|
||
|
|
// For example, if the key is "foo bar", then to access it our CLI
|
||
|
|
// must be accessed with "./cli foo bar". See the docs for CLI for
|
||
|
|
// notes on how this changes some other behavior of the CLI as well.
|
||
|
|
Commands map[string]CommandFactory
|
||
|
|
|
||
|
|
// Name defines the name of the CLI.
|
||
|
|
Name string
|
||
|
|
|
||
|
|
// Version of the CLI.
|
||
|
|
Version string
|
||
|
|
|
||
|
|
// HelpFunc and HelpWriter are used to output help information, if
|
||
|
|
// requested.
|
||
|
|
//
|
||
|
|
// HelpFunc is the function called to generate the generic help
|
||
|
|
// text that is shown if help must be shown for the CLI that doesn't
|
||
|
|
// pertain to a specific command.
|
||
|
|
//
|
||
|
|
// HelpWriter is the Writer where the help text is outputted to. If
|
||
|
|
// not specified, it will default to Stderr.
|
||
|
|
HelpFunc HelpFunc
|
||
|
|
HelpWriter io.Writer
|
||
|
|
|
||
|
|
once sync.Once
|
||
|
|
commandTree *radix.Tree
|
||
|
|
commandNested bool
|
||
|
|
isHelp bool
|
||
|
|
subcommand string
|
||
|
|
subcommandArgs []string
|
||
|
|
topFlags []string
|
||
|
|
|
||
|
|
isVersion bool
|
||
|
|
}
|
||
|
|
|
||
|
|
// NewClI returns a new CLI instance with sensible defaults.
|
||
|
|
func NewCLI(app, version string) *CLI {
|
||
|
|
return &CLI{
|
||
|
|
Name: app,
|
||
|
|
Version: version,
|
||
|
|
HelpFunc: BasicHelpFunc(app),
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
// IsHelp returns whether or not the help flag is present within the
|
||
|
|
// arguments.
|
||
|
|
func (c *CLI) IsHelp() bool {
|
||
|
|
c.once.Do(c.init)
|
||
|
|
return c.isHelp
|
||
|
|
}
|
||
|
|
|
||
|
|
// IsVersion returns whether or not the version flag is present within the
|
||
|
|
// arguments.
|
||
|
|
func (c *CLI) IsVersion() bool {
|
||
|
|
c.once.Do(c.init)
|
||
|
|
return c.isVersion
|
||
|
|
}
|
||
|
|
|
||
|
|
// Run runs the actual CLI based on the arguments given.
|
||
|
|
func (c *CLI) Run() (int, error) {
|
||
|
|
c.once.Do(c.init)
|
||
|
|
|
||
|
|
// Just show the version and exit if instructed.
|
||
|
|
if c.IsVersion() && c.Version != "" {
|
||
|
|
c.HelpWriter.Write([]byte(c.Version + "\n"))
|
||
|
|
return 1, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// Attempt to get the factory function for creating the command
|
||
|
|
// implementation. If the command is invalid or blank, it is an error.
|
||
|
|
raw, ok := c.commandTree.Get(c.Subcommand())
|
||
|
|
if !ok {
|
||
|
|
c.HelpWriter.Write([]byte(c.HelpFunc(c.helpCommands(c.subcommandParent())) + "\n"))
|
||
|
|
return 1, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
command, err := raw.(CommandFactory)()
|
||
|
|
if err != nil {
|
||
|
|
return 0, err
|
||
|
|
}
|
||
|
|
|
||
|
|
// If we've been instructed to just print the help, then print it
|
||
|
|
if c.IsHelp() {
|
||
|
|
c.commandHelp(command)
|
||
|
|
return 1, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// If there is an invalid flag, then error
|
||
|
|
if len(c.topFlags) > 0 {
|
||
|
|
c.HelpWriter.Write([]byte(
|
||
|
|
"Invalid flags before the subcommand. If these flags are for\n" +
|
||
|
|
"the subcommand, please put them after the subcommand.\n\n"))
|
||
|
|
c.commandHelp(command)
|
||
|
|
return 1, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
code := command.Run(c.SubcommandArgs())
|
||
|
|
if code == RunResultHelp {
|
||
|
|
// Requesting help
|
||
|
|
c.commandHelp(command)
|
||
|
|
return 1, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
return code, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// Subcommand returns the subcommand that the CLI would execute. For
|
||
|
|
// example, a CLI from "--version version --help" would return a Subcommand
|
||
|
|
// of "version"
|
||
|
|
func (c *CLI) Subcommand() string {
|
||
|
|
c.once.Do(c.init)
|
||
|
|
return c.subcommand
|
||
|
|
}
|
||
|
|
|
||
|
|
// SubcommandArgs returns the arguments that will be passed to the
|
||
|
|
// subcommand.
|
||
|
|
func (c *CLI) SubcommandArgs() []string {
|
||
|
|
c.once.Do(c.init)
|
||
|
|
return c.subcommandArgs
|
||
|
|
}
|
||
|
|
|
||
|
|
// subcommandParent returns the parent of this subcommand, if there is one.
|
||
|
|
// If there isn't on, "" is returned.
|
||
|
|
func (c *CLI) subcommandParent() string {
|
||
|
|
// Get the subcommand, if it is "" alread just return
|
||
|
|
sub := c.Subcommand()
|
||
|
|
if sub == "" {
|
||
|
|
return sub
|
||
|
|
}
|
||
|
|
|
||
|
|
// Clear any trailing spaces and find the last space
|
||
|
|
sub = strings.TrimRight(sub, " ")
|
||
|
|
idx := strings.LastIndex(sub, " ")
|
||
|
|
|
||
|
|
if idx == -1 {
|
||
|
|
// No space means our parent is root
|
||
|
|
return ""
|
||
|
|
}
|
||
|
|
|
||
|
|
return sub[:idx]
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c *CLI) init() {
|
||
|
|
if c.HelpFunc == nil {
|
||
|
|
c.HelpFunc = BasicHelpFunc("app")
|
||
|
|
|
||
|
|
if c.Name != "" {
|
||
|
|
c.HelpFunc = BasicHelpFunc(c.Name)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if c.HelpWriter == nil {
|
||
|
|
c.HelpWriter = os.Stderr
|
||
|
|
}
|
||
|
|
|
||
|
|
// Build our command tree
|
||
|
|
c.commandTree = radix.New()
|
||
|
|
c.commandNested = false
|
||
|
|
for k, v := range c.Commands {
|
||
|
|
k = strings.TrimSpace(k)
|
||
|
|
c.commandTree.Insert(k, v)
|
||
|
|
if strings.ContainsRune(k, ' ') {
|
||
|
|
c.commandNested = true
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Go through the key and fill in any missing parent commands
|
||
|
|
if c.commandNested {
|
||
|
|
var walkFn radix.WalkFn
|
||
|
|
toInsert := make(map[string]struct{})
|
||
|
|
walkFn = func(k string, raw interface{}) bool {
|
||
|
|
idx := strings.LastIndex(k, " ")
|
||
|
|
if idx == -1 {
|
||
|
|
// If there is no space, just ignore top level commands
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
|
||
|
|
// Trim up to that space so we can get the expected parent
|
||
|
|
k = k[:idx]
|
||
|
|
if _, ok := c.commandTree.Get(k); ok {
|
||
|
|
// Yay we have the parent!
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
|
||
|
|
// We're missing the parent, so let's insert this
|
||
|
|
toInsert[k] = struct{}{}
|
||
|
|
|
||
|
|
// Call the walk function recursively so we check this one too
|
||
|
|
return walkFn(k, nil)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Walk!
|
||
|
|
c.commandTree.Walk(walkFn)
|
||
|
|
|
||
|
|
// Insert any that we're missing
|
||
|
|
for k, _ := range toInsert {
|
||
|
|
var f CommandFactory = func() (Command, error) {
|
||
|
|
return &MockCommand{
|
||
|
|
HelpText: "This command is accessed by using one of the subcommands below.",
|
||
|
|
RunResult: RunResultHelp,
|
||
|
|
}, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
c.commandTree.Insert(k, f)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Process the args
|
||
|
|
c.processArgs()
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c *CLI) commandHelp(command Command) {
|
||
|
|
// Get the template to use
|
||
|
|
tpl := strings.TrimSpace(defaultHelpTemplate)
|
||
|
|
if t, ok := command.(CommandHelpTemplate); ok {
|
||
|
|
tpl = t.HelpTemplate()
|
||
|
|
}
|
||
|
|
if !strings.HasSuffix(tpl, "\n") {
|
||
|
|
tpl += "\n"
|
||
|
|
}
|
||
|
|
|
||
|
|
// Parse it
|
||
|
|
t, err := template.New("root").Parse(tpl)
|
||
|
|
if err != nil {
|
||
|
|
t = template.Must(template.New("root").Parse(fmt.Sprintf(
|
||
|
|
"Internal error! Failed to parse command help template: %s\n", err)))
|
||
|
|
}
|
||
|
|
|
||
|
|
// Template data
|
||
|
|
data := map[string]interface{}{
|
||
|
|
"Name": c.Name,
|
||
|
|
"Help": command.Help(),
|
||
|
|
}
|
||
|
|
|
||
|
|
// Build subcommand list if we have it
|
||
|
|
var subcommandsTpl []map[string]interface{}
|
||
|
|
if c.commandNested {
|
||
|
|
// Get the matching keys
|
||
|
|
subcommands := c.helpCommands(c.Subcommand())
|
||
|
|
keys := make([]string, 0, len(subcommands))
|
||
|
|
for k := range subcommands {
|
||
|
|
keys = append(keys, k)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Sort the keys
|
||
|
|
sort.Strings(keys)
|
||
|
|
|
||
|
|
// Figure out the padding length
|
||
|
|
var longest int
|
||
|
|
for _, k := range keys {
|
||
|
|
if v := len(k); v > longest {
|
||
|
|
longest = v
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Go through and create their structures
|
||
|
|
subcommandsTpl = make([]map[string]interface{}, 0, len(subcommands))
|
||
|
|
for _, k := range keys {
|
||
|
|
// Get the command
|
||
|
|
raw, ok := subcommands[k]
|
||
|
|
if !ok {
|
||
|
|
c.HelpWriter.Write([]byte(fmt.Sprintf(
|
||
|
|
"Error getting subcommand %q", k)))
|
||
|
|
}
|
||
|
|
sub, err := raw()
|
||
|
|
if err != nil {
|
||
|
|
c.HelpWriter.Write([]byte(fmt.Sprintf(
|
||
|
|
"Error instantiating %q: %s", k, err)))
|
||
|
|
}
|
||
|
|
|
||
|
|
// Find the last space and make sure we only include that last part
|
||
|
|
name := k
|
||
|
|
if idx := strings.LastIndex(k, " "); idx > -1 {
|
||
|
|
name = name[idx+1:]
|
||
|
|
}
|
||
|
|
|
||
|
|
subcommandsTpl = append(subcommandsTpl, map[string]interface{}{
|
||
|
|
"Name": name,
|
||
|
|
"NameAligned": name + strings.Repeat(" ", longest-len(k)),
|
||
|
|
"Help": sub.Help(),
|
||
|
|
"Synopsis": sub.Synopsis(),
|
||
|
|
})
|
||
|
|
}
|
||
|
|
}
|
||
|
|
data["Subcommands"] = subcommandsTpl
|
||
|
|
|
||
|
|
// Write
|
||
|
|
err = t.Execute(c.HelpWriter, data)
|
||
|
|
if err == nil {
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
// An error, just output...
|
||
|
|
c.HelpWriter.Write([]byte(fmt.Sprintf(
|
||
|
|
"Internal error rendering help: %s", err)))
|
||
|
|
}
|
||
|
|
|
||
|
|
// helpCommands returns the subcommands for the HelpFunc argument.
|
||
|
|
// This will only contain immediate subcommands.
|
||
|
|
func (c *CLI) helpCommands(prefix string) map[string]CommandFactory {
|
||
|
|
// If our prefix isn't empty, make sure it ends in ' '
|
||
|
|
if prefix != "" && prefix[len(prefix)-1] != ' ' {
|
||
|
|
prefix += " "
|
||
|
|
}
|
||
|
|
|
||
|
|
// Get all the subkeys of this command
|
||
|
|
var keys []string
|
||
|
|
c.commandTree.WalkPrefix(prefix, func(k string, raw interface{}) bool {
|
||
|
|
// Ignore any sub-sub keys, i.e. "foo bar baz" when we want "foo bar"
|
||
|
|
if !strings.Contains(k[len(prefix):], " ") {
|
||
|
|
keys = append(keys, k)
|
||
|
|
}
|
||
|
|
|
||
|
|
return false
|
||
|
|
})
|
||
|
|
|
||
|
|
// For each of the keys return that in the map
|
||
|
|
result := make(map[string]CommandFactory, len(keys))
|
||
|
|
for _, k := range keys {
|
||
|
|
raw, ok := c.commandTree.Get(k)
|
||
|
|
if !ok {
|
||
|
|
// We just got it via WalkPrefix above, so we just panic
|
||
|
|
panic("not found: " + k)
|
||
|
|
}
|
||
|
|
|
||
|
|
result[k] = raw.(CommandFactory)
|
||
|
|
}
|
||
|
|
|
||
|
|
return result
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c *CLI) processArgs() {
|
||
|
|
for i, arg := range c.Args {
|
||
|
|
if c.subcommand == "" {
|
||
|
|
// Check for version and help flags if not in a subcommand
|
||
|
|
if arg == "-v" || arg == "-version" || arg == "--version" {
|
||
|
|
c.isVersion = true
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
if arg == "-h" || arg == "-help" || arg == "--help" {
|
||
|
|
c.isHelp = true
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
|
||
|
|
if arg != "" && arg[0] == '-' {
|
||
|
|
// Record the arg...
|
||
|
|
c.topFlags = append(c.topFlags, arg)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// If we didn't find a subcommand yet and this is the first non-flag
|
||
|
|
// argument, then this is our subcommand.
|
||
|
|
if c.subcommand == "" && arg != "" && arg[0] != '-' {
|
||
|
|
c.subcommand = arg
|
||
|
|
if c.commandNested {
|
||
|
|
// Nested CLI, the subcommand is actually the entire
|
||
|
|
// arg list up to a flag that is still a valid subcommand.
|
||
|
|
searchKey := strings.Join(c.Args[i:], " ")
|
||
|
|
k, _, ok := c.commandTree.LongestPrefix(searchKey)
|
||
|
|
if ok {
|
||
|
|
// k could be a prefix that doesn't contain the full
|
||
|
|
// command such as "foo" instead of "foobar", so we
|
||
|
|
// need to verify that we have an entire key. To do that,
|
||
|
|
// we look for an ending in a space or an end of string.
|
||
|
|
reVerify := regexp.MustCompile(regexp.QuoteMeta(k) + `( |$)`)
|
||
|
|
if reVerify.MatchString(searchKey) {
|
||
|
|
c.subcommand = k
|
||
|
|
i += strings.Count(k, " ")
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// The remaining args the subcommand arguments
|
||
|
|
c.subcommandArgs = c.Args[i+1:]
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// If we never found a subcommand and support a default command, then
|
||
|
|
// switch to using that.
|
||
|
|
if c.subcommand == "" {
|
||
|
|
if _, ok := c.Commands[""]; ok {
|
||
|
|
args := c.topFlags
|
||
|
|
args = append(args, c.subcommandArgs...)
|
||
|
|
c.topFlags = nil
|
||
|
|
c.subcommandArgs = args
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
const defaultHelpTemplate = `
|
||
|
|
{{.Help}}{{if gt (len .Subcommands) 0}}
|
||
|
|
|
||
|
|
Subcommands:
|
||
|
|
{{ range $value := .Subcommands }}
|
||
|
|
{{ $value.NameAligned }} {{ $value.Synopsis }}{{ end }}
|
||
|
|
{{ end }}
|
||
|
|
`
|