package ipc import ( "errors" "fmt" "io" "io/ioutil" "reflect" "github.com/docker/libchan" ) // Request defines a remote method call request // A return value struct is to be sent over the ResponseChannel type Request struct { Type string Parameters map[string]interface{} ResponseChannel libchan.Sender } // noWriteReadWriteCloser is a simple wrapper around an io.ReadCloser that implements the // io.ReadWriteCloser interface // Calls to Write are disallowed and will return an error type noWriteReadWriteCloser struct { io.ReadCloser } func (r noWriteReadWriteCloser) Write(p []byte) (n int, err error) { return 0, errors.New("Write unsupported") } // WrapReader wraps an io.Reader as an io.ReadWriteCloser with a nop Close and unsupported Write // Has no effect when an io.ReadWriteCloser is passed in func WrapReader(reader io.Reader) io.ReadWriteCloser { if readWriteCloser, ok := reader.(io.ReadWriteCloser); ok { return readWriteCloser } else if readCloser, ok := reader.(io.ReadCloser); ok { return noWriteReadWriteCloser{readCloser} } else { return noWriteReadWriteCloser{ioutil.NopCloser(reader)} } } type responseError struct { Type string Message string } // ResponseError wraps an error in a serializable struct containing the error's type and message func ResponseError(err error) *responseError { if err == nil { return nil } return &responseError{ Type: reflect.TypeOf(err).String(), Message: err.Error(), } } func (err *responseError) Error() string { return fmt.Sprintf("%s: %s", err.Type, err.Message) } // IPC method call response object definitions // ReadStreamResponse is a response for a ReadStream request type ReadStreamResponse struct { Reader io.ReadWriteCloser Error *responseError } // WriteStreamResponse is a response for a WriteStream request type WriteStreamResponse struct { Error *responseError } // ResumeWritePositionResponse is a response for a ResumeWritePosition request type ResumeWritePositionResponse struct { Position uint64 Error *responseError } // ListResponse is a response for a List request type ListResponse struct { Keys []string Error *responseError } // MoveResponse is a response for a Move request type MoveResponse struct { Error *responseError } // DeleteResponse is a response for a Delete request type DeleteResponse struct { Error *responseError }