| // Licensed to the Apache Software Foundation (ASF) under one or more |
| // contributor license agreements. See the NOTICE file distributed with |
| // this work for additional information regarding copyright ownership. |
| // The ASF licenses this file to You under the Apache License, Version 2.0 |
| // (the "License"); you may not use this file except in compliance with |
| // the License. You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package exec |
| |
| import ( |
| "context" |
| "fmt" |
| "io" |
| ) |
| |
| // Port represents the connection port of external operations. |
| type Port struct { |
| URL string |
| } |
| |
| // Target represents the static target of external operations. |
| type Target struct { |
| // ID is the transform ID. |
| ID string |
| // Name is a local name in the context of the transform. |
| Name string |
| } |
| |
| // StreamID represents the static information needed to identify |
| // a data stream. Dynamic information, notably bundleID, is provided |
| // implicitly by the managers. |
| type StreamID struct { |
| Port Port |
| Target Target |
| } |
| |
| func (id StreamID) String() string { |
| return fmt.Sprintf("S[%v:%v@%v]", id.Target.ID, id.Target.Name, id.Port.URL) |
| } |
| |
| // DataContext holds connectors to various data connections, incl. state and side input. |
| type DataContext struct { |
| Data DataManager |
| SideInput SideInputReader |
| } |
| |
| // DataManager manages external data byte streams. Each data stream can be |
| // opened by one consumer only. |
| type DataManager interface { |
| // OpenRead opens a closable byte stream for reading. |
| OpenRead(ctx context.Context, id StreamID) (io.ReadCloser, error) |
| // OpenWrite opens a closable byte stream for writing. |
| OpenWrite(ctx context.Context, id StreamID) (io.WriteCloser, error) |
| } |
| |
| // SideInputReader is the interface for reading side input data. |
| type SideInputReader interface { |
| // Open opens a byte stream for reading iterable side input. |
| Open(ctx context.Context, id StreamID, key, w []byte) (io.ReadCloser, error) |
| } |
| |
| // TODO(herohde) 7/20/2018: user state management |