packer-cn/packer/rpc/builder.go

155 lines
3.1 KiB
Go

package rpc
import (
"encoding/gob"
"github.com/mitchellh/packer/packer"
"log"
"net"
"net/rpc"
)
// An implementation of packer.Builder where the builder is actually executed
// over an RPC connection.
type builder struct {
client *rpc.Client
}
// BuilderServer wraps a packer.Builder implementation and makes it exportable
// as part of a Golang RPC server.
type BuilderServer struct {
builder packer.Builder
}
type BuilderPrepareArgs struct {
Config interface{}
}
type BuilderRunArgs struct {
RPCAddress string
ResponseAddress string
}
type BuilderRunResponse struct {
RPCAddress string
}
func Builder(client *rpc.Client) *builder {
return &builder{client}
}
func (b *builder) Prepare(config interface{}) (err error) {
cerr := b.client.Call("Builder.Prepare", &BuilderPrepareArgs{config}, &err)
if cerr != nil {
err = cerr
}
return
}
func (b *builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) packer.Artifact {
// Create and start the server for the Build and UI
server := rpc.NewServer()
RegisterCache(server, cache)
RegisterHook(server, hook)
RegisterUi(server, ui)
// Create a server for the response
responseL := netListenerInRange(portRangeMin, portRangeMax)
artifactAddress := make(chan string)
go func() {
defer responseL.Close()
conn, err := responseL.Accept()
if err != nil {
log.Panic(err)
}
defer conn.Close()
decoder := gob.NewDecoder(conn)
var response BuilderRunResponse
if err := decoder.Decode(&response); err != nil {
log.Panic(err)
}
artifactAddress <- response.RPCAddress
}()
args := &BuilderRunArgs{
serveSingleConn(server),
responseL.Addr().String(),
}
if err := b.client.Call("Builder.Run", args, new(interface{})); err != nil {
panic(err)
}
address := <-artifactAddress
if address == "" {
return nil
}
client, err := rpc.Dial("tcp", address)
if err != nil {
panic(err)
}
return Artifact(client)
}
func (b *builder) Cancel() {
if err := b.client.Call("Builder.Cancel", new(interface{}), new(interface{})); err != nil {
panic(err)
}
}
func (b *BuilderServer) Prepare(args *BuilderPrepareArgs, reply *error) error {
err := b.builder.Prepare(args.Config)
if err != nil {
*reply = NewBasicError(err)
}
return nil
}
func (b *BuilderServer) Run(args *BuilderRunArgs, reply *interface{}) error {
client, err := rpc.Dial("tcp", args.RPCAddress)
if err != nil {
return err
}
responseC, err := net.Dial("tcp", args.ResponseAddress)
if err != nil {
return err
}
responseWriter := gob.NewEncoder(responseC)
// Run the build in a goroutine so we don't block the RPC connection
go func() {
defer responseC.Close()
cache := Cache(client)
hook := Hook(client)
ui := &Ui{client}
artifact := b.builder.Run(ui, hook, cache)
responseAddress := ""
if artifact != nil {
// Wrap the artifact
server := rpc.NewServer()
RegisterArtifact(server, artifact)
responseAddress = serveSingleConn(server)
}
responseWriter.Encode(&BuilderRunResponse{responseAddress})
}()
return nil
}
func (b *BuilderServer) Cancel(args *interface{}, reply *interface{}) error {
b.builder.Cancel()
return nil
}