consul/command/registry.go

89 lines
2.4 KiB
Go

package command
import (
"fmt"
"os"
"os/signal"
"syscall"
"github.com/mitchellh/cli"
)
// Factory is a function that returns a new instance of a CLI-sub command.
type Factory func(cli.Ui) (cli.Command, error)
// Register adds a new CLI sub-command to the registry.
func Register(name string, fn Factory) {
if registry == nil {
registry = make(map[string]Factory)
}
if registry[name] != nil {
panic(fmt.Errorf("Command %q is already registered", name))
}
registry[name] = fn
}
// RegisterHidden adds a new CLI sub-command to the registry that won't show up
// in help or autocomplete.
func RegisterHidden(name string, fn Factory) {
if hiddenRegistry == nil {
hiddenRegistry = make(map[string]Factory)
}
if hiddenRegistry[name] != nil {
panic(fmt.Errorf("Command %q is already registered", name))
}
hiddenRegistry[name] = fn
}
// Map returns a realized mapping of available CLI commands in a format that
// the CLI class can consume. This should be called after all registration is
// complete.
func Map(ui cli.Ui) map[string]cli.CommandFactory {
return makeCommands(ui, registry)
}
// Map returns a realized mapping of available but hidden CLI commands in a
// format that the CLI class can consume. This should be called after all
// registration is complete.
func MapHidden(ui cli.Ui) map[string]cli.CommandFactory {
return makeCommands(ui, hiddenRegistry)
}
func makeCommands(ui cli.Ui, reg map[string]Factory) map[string]cli.CommandFactory {
m := make(map[string]cli.CommandFactory)
for name, fn := range reg {
thisFn := fn
m[name] = func() (cli.Command, error) {
return thisFn(ui)
}
}
return m
}
// registry has an entry for each available CLI sub-command, indexed by sub
// command name. This should be populated at package init() time via Register().
var registry map[string]Factory
// hiddenRegistry behaves identically to registry but is for commands that are
// hidden - i.e. not publically documented in the help or autocomplete.
var hiddenRegistry map[string]Factory
// MakeShutdownCh returns a channel that can be used for shutdown notifications
// for commands. This channel will send a message for every interrupt or SIGTERM
// received.
func MakeShutdownCh() <-chan struct{} {
resultCh := make(chan struct{})
signalCh := make(chan os.Signal, 4)
signal.Notify(signalCh, os.Interrupt, syscall.SIGTERM)
go func() {
for {
<-signalCh
resultCh <- struct{}{}
}
}()
return resultCh
}