packer-cn/packer/plugin/builder.go

77 lines
1.5 KiB
Go

package plugin
import (
"github.com/mitchellh/packer/packer"
"log"
"net/rpc"
"os/exec"
packrpc "github.com/mitchellh/packer/packer/rpc"
)
type cmdBuilder struct {
builder packer.Builder
client *client
}
func (b *cmdBuilder) Prepare(config interface{}) error {
defer func() {
r := recover()
b.checkExit(r, nil)
}()
return b.builder.Prepare(config)
}
func (b *cmdBuilder) Run(build packer.Build, ui packer.Ui) {
defer func() {
r := recover()
b.checkExit(r, nil)
}()
b.builder.Run(build, ui)
}
func (c *cmdBuilder) checkExit(p interface{}, cb func()) {
if c.client.Exited() && cb != nil {
cb()
} else if p != nil {
log.Panic(p)
}
}
// Returns a valid packer.Builder where the builder 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 Builder(cmd *exec.Cmd) (result packer.Builder, 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 = &cmdBuilder{
packrpc.Builder(client),
cmdClient,
}
return
}