package rpc import ( "context" "log" "net/rpc" "github.com/hashicorp/packer/packer" ) // An implementation of packer.Provisioner where the provisioner is actually // executed over an RPC connection. type provisioner struct { client *rpc.Client mux *muxBroker } // ProvisionerServer wraps a packer.Provisioner implementation and makes it // exportable as part of a Golang RPC server. type ProvisionerServer struct { context context.Context contextCancel func() p packer.Provisioner mux *muxBroker } type ProvisionerPrepareArgs struct { Configs []interface{} } func (p *provisioner) Prepare(configs ...interface{}) (err error) { args := &ProvisionerPrepareArgs{configs} if cerr := p.client.Call("Provisioner.Prepare", args, new(interface{})); cerr != nil { err = cerr } return } func (p *provisioner) Provision(ctx context.Context, ui packer.Ui, comm packer.Communicator) error { nextId := p.mux.NextId() server := newServerWithMux(p.mux, nextId) server.RegisterCommunicator(comm) server.RegisterUi(ui) go server.Serve() done := make(chan interface{}) defer close(done) go func() { select { case <-ctx.Done(): log.Printf("Cancelling provisioner after context cancellation %v", ctx.Err()) if err := p.client.Call("Provisioner.Cancel", new(interface{}), new(interface{})); err != nil { log.Printf("Error cancelling provisioner: %s", err) } case <-done: } }() return p.client.Call("Provisioner.Provision", nextId, new(interface{})) } func (p *ProvisionerServer) Prepare(args *ProvisionerPrepareArgs, reply *interface{}) error { return p.p.Prepare(args.Configs...) } func (p *ProvisionerServer) Provision(streamId uint32, reply *interface{}) error { client, err := newClientWithMux(p.mux, streamId) if err != nil { return NewBasicError(err) } defer client.Close() if p.context == nil { p.context, p.contextCancel = context.WithCancel(context.Background()) } if err := p.p.Provision(p.context, client.Ui(), client.Communicator()); err != nil { return NewBasicError(err) } return nil } func (p *ProvisionerServer) Cancel(args *interface{}, reply *interface{}) error { p.contextCancel() return nil }