Gosh - 一个用于构建命令shell程序的可插拔框架（gosh主理人）

Gosh - A pluggable interactive shell written Go

Gosh (or Go shell) is a framework that uses Go's plugin system to create for building interactive console-based shell programs. A gosh shell is comprised of a collection of Go plugins which implement one or more commands. When gosh starts, it searches directory ./plugins for available shared object files that implement command plugins.

Getting started

Pre-requisites

Go 1.8 or aboveLinuxMac OSX

Gosh makes it easy to create shell programs. First, download or clone this repository. For a quick start, run the following:

go run shell/gosh.go

This will produce the following output:

888 888 888 .d88b. .d88b. .d8888b 88888b.d88P"88bd88""88b88K 888 "88b888 888888 888"Y8888b.888 888Y88b 888Y88..88P X88888 888 "Y88888 "Y88P" 88888P'888 888 888Y8b d88P "Y88P"No commands found

After the splashscreen is displayed, gosh informs you that no commands found, as expected. Next, exit the gosh shell (Ctrl-C) and let us compile the example plugins that comes with the source code.

go build -buildmode=plugin -o plugins/sys_command.so plugins/syscmd.go

The previous command will compile plugins/syscmd.go and outputs shared object plugins/sys_command.so, as a Go plugin file. Verify the shared object file was created:

> ls -lh plugins/total 3.2M-rw-rw-r-- 1 4.5K Mar 19 18:23 syscmd.go-rw-rw-r-- 1 3.2M Mar 19 19:14 sys_command.so-rw-rw-r-- 1 1.4K Mar 19 18:23 testcmd.go

Now, when gosh is restarted, it will dynamically load the commands implemented in the shared object file:

> go run shell/gosh.go...Loaded 4 command(s)...Type help for available commandsgosh>

As indicated, typing help lists all available commands in the shell:

gosh> helphelp: prints help information for other commands.Available commands------------------ prompt: sets a new shell prompt sys: sets a new shell prompt help: prints help information for other commands. exit: exits the interactive shell immediatelyUse "help " for detail about the specified command

A command

A Gosh Command is represented by type api/Command:

type Command interface { Name() string Usage() string ShortDesc() string LongDesc() string Exec(context.Context, []string) (context.Context, error)}

The Gosh framework searches for Go plugin files in the ./plugins directory. Each package plugin must export a variable named Commands which is of type :

type Commands interface { ... Registry() map[string]Command}

Type Commands type returns a list of Command via the Registry().

The following shows example command file plugins/testcmd.go. It implements two commands via types helloCmd and goodbyeCmd. The commands are exported via type testCmds using method Registry():

package mainimport ( "context" "fmt" "io" "github.com/vladimirvivien/gosh/api")type helloCmd stringfunc (t helloCmd) Name() string { return string(t) }func (t helloCmd) Usage() string { return `hello` }func (t helloCmd) ShortDesc() string { return `prints greeting "hello there"` }func (t helloCmd) LongDesc() string { return t.ShortDesc() }func (t helloCmd) Exec(ctx context.Context, args []string) (context.Context, error) { out := ctx.Value("gosh.stdout").(io.Writer) fmt.Fprintln(out, "hello there") return ctx, nil}type goodbyeCmd stringfunc (t goodbyeCmd) Name() string { return string(t) }func (t goodbyeCmd) Usage() string { return t.Name() }func (t goodbyeCmd) ShortDesc() string { return `prints message "bye bye"` }func (t goodbyeCmd) LongDesc() string { return t.ShortDesc() }func (t goodbyeCmd) Exec(ctx context.Context, args []string) (context.Context, error) { out := ctx.Value("gosh.stdout").(io.Writer) fmt.Fprintln(out, "bye bye") return ctx, nil}// command moduletype testCmds struct{}func (t *testCmds) Init(ctx context.Context) error { out := ctx.Value("gosh.stdout").(io.Writer) fmt.Fprintln(out, "test module loaded OK") return nil}func (t *testCmds) Registry() map[string]api.Command { return map[string]api.Command{ "hello": helloCmd("hello"), "goodbye": goodbyeCmd("goodbye"), }}var Commands testCmds

License

MIT

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