63 lines
1.4 KiB
Go
63 lines
1.4 KiB
Go
|
package engine
|
||
|
|
|
||
|
|
import (
|
||
|
|
"fmt"
|
||
|
|
"os"
|
||
|
|
)
|
||
|
|
|
||
|
|
|
||
|
|
type Handler func(*Job) string
|
||
|
|
|
||
|
|
var globalHandlers map[string]Handler
|
||
|
|
|
||
|
|
func Register(name string, handler Handler) error {
|
||
|
|
if globalHandlers == nil {
|
||
|
|
globalHandlers = make(map[string]Handler)
|
||
|
|
}
|
||
|
|
globalHandlers[name] = handler
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// The Engine is the core of Docker.
|
||
|
|
// It acts as a store for *containers*, and allows manipulation of these
|
||
|
|
// containers by executing *jobs*.
|
||
|
|
type Engine struct {
|
||
|
|
root string
|
||
|
|
handlers map[string]Handler
|
||
|
|
}
|
||
|
|
|
||
|
|
// New initializes a new engine managing the directory specified at `root`.
|
||
|
|
// `root` is used to store containers and any other state private to the engine.
|
||
|
|
// Changing the contents of the root without executing a job will cause unspecified
|
||
|
|
// behavior.
|
||
|
|
func New(root string) (*Engine, error) {
|
||
|
|
if err := os.MkdirAll(root, 0700); err != nil && !os.IsExist(err) {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
eng := &Engine{
|
||
|
|
root: root,
|
||
|
|
handlers: globalHandlers,
|
||
|
|
}
|
||
|
|
return eng, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// Job creates a new job which can later be executed.
|
||
|
|
// This function mimics `Command` from the standard os/exec package.
|
||
|
|
func (eng *Engine) Job(name string, args ...string) (*Job, error) {
|
||
|
|
handler, exists := eng.handlers[name]
|
||
|
|
if !exists || handler == nil {
|
||
|
|
return nil, fmt.Errorf("Undefined command; %s", name)
|
||
|
|
}
|
||
|
|
job := &Job{
|
||
|
|
eng: eng,
|
||
|
|
Name: name,
|
||
|
|
Args: args,
|
||
|
|
Stdin: os.Stdin,
|
||
|
|
Stdout: os.Stdout,
|
||
|
|
Stderr: os.Stderr,
|
||
|
|
handler: handler,
|
||
|
|
}
|
||
|
|
return job, nil
|
||
|
|
}
|
||
|
|
|