| /* |
| * 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 whisk |
| |
| import ( |
| "bufio" |
| "encoding/json" |
| "fmt" |
| "io" |
| "log" |
| "os" |
| ) |
| |
| // ActionFunction is the signature of an action in OpenWhisk |
| type ActionFunction func(event json.RawMessage) (json.RawMessage, error) |
| |
| // actual implementation of a read-eval-print-loop |
| func repl(fn ActionFunction, in io.Reader, out io.Writer) { |
| // read loop |
| reader := bufio.NewReader(in) |
| for { |
| event, err := reader.ReadBytes('\n') |
| if err != nil { |
| break |
| } |
| result, err := fn(event) |
| if err != nil { |
| fmt.Fprintf(out, "{ error: %q}\n", err.Error()) |
| continue |
| } |
| fmt.Fprintln(out, string(result)) |
| } |
| } |
| |
| // Start will start a loop reading in stdin and outputting in fd3 |
| // This is expected to be uses for implementing Go actions |
| func Start(fn ActionFunction) { |
| out := os.NewFile(3, "pipe") |
| defer out.Close() |
| repl(fn, os.Stdin, out) |
| } |
| |
| // StartWithArgs will execute the function for each arg |
| // If there are no args it will start a read-write loop on the function |
| // Expected to be used as starting point for implementing Go Actions |
| // as whisk.StartWithArgs(function, os.Args[:1]) |
| // if args are 2 (command and one parameter) it will invoke the function once |
| // otherwise it will stat the function in a read-write loop |
| func StartWithArgs(action ActionFunction, args []string) { |
| // handle command line argument |
| if len(args) > 0 { |
| for _, arg := range args { |
| log.Println(arg) |
| result, err := action([]byte(arg)) |
| if err == nil { |
| fmt.Println(string(result)) |
| } else { |
| log.Println(err) |
| } |
| } |
| return |
| } |
| Start(action) |
| } |