grpc_api_configuration.go

Documentation: github.com/grpc-ecosystem/grpc-gateway/protoc-gen-grpc-gateway/descriptor

     1  package descriptor
     2  
     3  import (
     4  	"bytes"
     5  	"fmt"
     6  	"io/ioutil"
     7  	"strings"
     8  
     9  	"github.com/ghodss/yaml"
    10  	"github.com/golang/protobuf/jsonpb"
    11  )
    12  
    13  func loadGrpcAPIServiceFromYAML(yamlFileContents []byte, yamlSourceLogName string) (*GrpcAPIService, error) {
    14  	jsonContents, err := yaml.YAMLToJSON(yamlFileContents)
    15  	if err != nil {
    16  		return nil, fmt.Errorf("Failed to convert gRPC API Configuration from YAML in '%v' to JSON: %v", yamlSourceLogName, err)
    17  	}
    18  
    19  	// As our GrpcAPIService is incomplete accept unknown fields.
    20  	unmarshaler := jsonpb.Unmarshaler{
    21  		AllowUnknownFields: true,
    22  	}
    23  
    24  	serviceConfiguration := GrpcAPIService{}
    25  	if err := unmarshaler.Unmarshal(bytes.NewReader(jsonContents), &serviceConfiguration); err != nil {
    26  		return nil, fmt.Errorf("Failed to parse gRPC API Configuration from YAML in '%v': %v", yamlSourceLogName, err)
    27  	}
    28  
    29  	return &serviceConfiguration, nil
    30  }
    31  
    32  func registerHTTPRulesFromGrpcAPIService(registry *Registry, service *GrpcAPIService, sourceLogName string) error {
    33  	if service.HTTP == nil {
    34  		// Nothing to do
    35  		return nil
    36  	}
    37  
    38  	for _, rule := range service.HTTP.GetRules() {
    39  		selector := "." + strings.Trim(rule.GetSelector(), " ")
    40  		if strings.ContainsAny(selector, "*, ") {
    41  			return fmt.Errorf("Selector '%v' in %v must specify a single service method without wildcards", rule.GetSelector(), sourceLogName)
    42  		}
    43  
    44  		registry.AddExternalHTTPRule(selector, rule)
    45  	}
    46  
    47  	return nil
    48  }
    49  
    50  // LoadGrpcAPIServiceFromYAML loads a gRPC API Configuration from the given YAML file
    51  // and registers the HttpRule descriptions contained in it as externalHTTPRules in
    52  // the given registry. This must be done before loading the proto file.
    53  //
    54  // You can learn more about gRPC API Service descriptions from google's documentation
    55  // at https://cloud.google.com/endpoints/docs/grpc/grpc-service-config
    56  //
    57  // Note that for the purposes of the gateway generator we only consider a subset of all
    58  // available features google supports in their service descriptions.
    59  func (r *Registry) LoadGrpcAPIServiceFromYAML(yamlFile string) error {
    60  	yamlFileContents, err := ioutil.ReadFile(yamlFile)
    61  	if err != nil {
    62  		return fmt.Errorf("Failed to read gRPC API Configuration description from '%v': %v", yamlFile, err)
    63  	}
    64  
    65  	service, err := loadGrpcAPIServiceFromYAML(yamlFileContents, yamlFile)
    66  	if err != nil {
    67  		return err
    68  	}
    69  
    70  	return registerHTTPRulesFromGrpcAPIService(r, service, yamlFile)
    71  }
    72
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