packer-cn/packer/rpc/builder.go

130 lines
2.8 KiB
Go

package rpc
import (
"context"
"log"
"net/rpc"
"github.com/hashicorp/packer/packer"
)
// An implementation of packer.Builder where the builder is actually executed
// over an RPC connection.
type builder struct {
client *rpc.Client
mux *muxBroker
}
// BuilderServer wraps a packer.Builder implementation and makes it exportable
// as part of a Golang RPC server.
type BuilderServer struct {
context context.Context
contextCancel func()
builder packer.Builder
mux *muxBroker
}
type BuilderPrepareArgs struct {
Configs []interface{}
}
type BuilderPrepareResponse struct {
Warnings []string
Error *BasicError
}
func (b *builder) Prepare(config ...interface{}) ([]string, error) {
var resp BuilderPrepareResponse
cerr := b.client.Call("Builder.Prepare", &BuilderPrepareArgs{config}, &resp)
if cerr != nil {
return nil, cerr
}
var err error = nil
if resp.Error != nil {
err = resp.Error
}
return resp.Warnings, err
}
func (b *builder) Run(ctx context.Context, ui packer.Ui, hook packer.Hook) (packer.Artifact, error) {
nextId := b.mux.NextId()
server := newServerWithMux(b.mux, nextId)
server.RegisterHook(hook)
server.RegisterUi(ui)
go server.Serve()
done := make(chan interface{})
defer close(done)
go func() {
select {
case <-ctx.Done():
log.Printf("Cancelling builder after context cancellation %v", ctx.Err())
if err := b.client.Call("Builder.Cancel", new(interface{}), new(interface{})); err != nil {
log.Printf("Error cancelling builder: %s", err)
}
case <-done:
}
}()
var responseId uint32
if err := b.client.Call("Builder.Run", nextId, &responseId); err != nil {
return nil, err
}
if responseId == 0 {
return nil, nil
}
client, err := newClientWithMux(b.mux, responseId)
if err != nil {
return nil, err
}
return client.Artifact(), nil
}
func (b *BuilderServer) Prepare(args *BuilderPrepareArgs, reply *BuilderPrepareResponse) error {
warnings, err := b.builder.Prepare(args.Configs...)
*reply = BuilderPrepareResponse{
Warnings: warnings,
Error: NewBasicError(err),
}
return nil
}
func (b *BuilderServer) Run(streamId uint32, reply *uint32) error {
client, err := newClientWithMux(b.mux, streamId)
if err != nil {
return NewBasicError(err)
}
defer client.Close()
if b.context == nil {
b.context, b.contextCancel = context.WithCancel(context.Background())
}
artifact, err := b.builder.Run(b.context, client.Ui(), client.Hook())
if err != nil {
return NewBasicError(err)
}
*reply = 0
if artifact != nil {
streamId = b.mux.NextId()
artifactServer := newServerWithMux(b.mux, streamId)
artifactServer.RegisterArtifact(artifact)
go artifactServer.Serve()
*reply = streamId
}
return nil
}
func (b *BuilderServer) Cancel(args *interface{}, reply *interface{}) error {
b.contextCancel()
return nil
}