extensions.go

Documentation: github.com/google/gnostic-models/extensions

     1  // Copyright 2017 Google LLC. All Rights Reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //    http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package gnostic_extension_v1
    16  
    17  import (
    18  	"io/ioutil"
    19  	"log"
    20  	"os"
    21  
    22  	"google.golang.org/protobuf/proto"
    23  	"google.golang.org/protobuf/types/known/anypb"
    24  )
    25  
    26  type extensionHandler func(name string, yamlInput string) (bool, proto.Message, error)
    27  
    28  // Main implements the main program of an extension handler.
    29  func Main(handler extensionHandler) {
    30  	// unpack the request
    31  	data, err := ioutil.ReadAll(os.Stdin)
    32  	if err != nil {
    33  		log.Println("File error:", err.Error())
    34  		os.Exit(1)
    35  	}
    36  	if len(data) == 0 {
    37  		log.Println("No input data.")
    38  		os.Exit(1)
    39  	}
    40  	request := &ExtensionHandlerRequest{}
    41  	err = proto.Unmarshal(data, request)
    42  	if err != nil {
    43  		log.Println("Input error:", err.Error())
    44  		os.Exit(1)
    45  	}
    46  	// call the handler
    47  	handled, output, err := handler(request.Wrapper.ExtensionName, request.Wrapper.Yaml)
    48  	// respond with the output of the handler
    49  	response := &ExtensionHandlerResponse{
    50  		Handled: false, // default assumption
    51  		Errors:  make([]string, 0),
    52  	}
    53  	if err != nil {
    54  		response.Errors = append(response.Errors, err.Error())
    55  	} else if handled {
    56  		response.Handled = true
    57  		response.Value, err = anypb.New(output)
    58  		if err != nil {
    59  			response.Errors = append(response.Errors, err.Error())
    60  		}
    61  	}
    62  	responseBytes, _ := proto.Marshal(response)
    63  	os.Stdout.Write(responseBytes)
    64  }
    65
View as plain text