packer-cn/packer/plugin/command.go

90 lines
1.7 KiB
Go

package plugin
import (
"github.com/mitchellh/packer/packer"
packrpc "github.com/mitchellh/packer/packer/rpc"
"log"
"net/rpc"
"os/exec"
)
type cmdCommand struct {
command packer.Command
client *client
}
func (c *cmdCommand) Help() (result string) {
defer func() {
r := recover()
c.checkExit(r, func() { result = "" })
}()
result = c.command.Help()
return
}
func (c *cmdCommand) Run(e packer.Environment, args []string) (exitCode int) {
defer func() {
r := recover()
c.checkExit(r, func() { exitCode = 1 })
}()
exitCode = c.command.Run(e, args)
return
}
func (c *cmdCommand) Synopsis() (result string) {
defer func() {
r := recover()
c.checkExit(r, func() {
result = ""
})
}()
result = c.command.Synopsis()
return
}
func (c *cmdCommand) checkExit(p interface{}, cb func()) {
if c.client.Exited() {
cb()
} else if p != nil {
log.Panic(p)
}
}
// Returns a valid packer.Command where the command is executed via RPC
// to a plugin that is within a subprocess.
//
// This method will start the given exec.Cmd, which should point to
// the plugin binary to execute. Some configuration will be done to
// the command, such as overriding Stdout and some environmental variables.
//
// This function guarantees the subprocess will end in a timely manner.
func Command(cmd *exec.Cmd) (result packer.Command, err error) {
cmdClient := NewManagedClient(cmd)
address, err := cmdClient.Start()
if err != nil {
return
}
defer func() {
// Make sure the command is properly killed in the case of an error
if err != nil {
cmdClient.Kill()
}
}()
client, err := rpc.Dial("tcp", address)
if err != nil {
return
}
result = &cmdCommand{
packrpc.Command(client),
cmdClient,
}
return
}