GrpcClient

Implements: IOpenable, IReferenceable, IConfigurable

Description

The GrpcClient class allows you to create clients that call remote endpoints using the GRPC protocol.

Configuration parameters

• connection(s):
  • discovery_key: (optional) key to retrieve the connection from IDiscovery
  • protocol: connection protocol: http or https
  • host: host name or IP address
  • port: port number
  • uri: resource URI or connection string with all parameters in it
• options:
  • retries: number of retries (default: 3)
  • connect_timeout: connection timeout in milliseconds (default: 10 sec)
  • timeout: invocation timeout in milliseconds (default: 10 sec)

Constructors

Creates a new instance of the grpc client.

NewGrpcClient(name string) *GrpcClient

• name: string - service name.

Fields

Methods

AddInterceptors

AddInterceptors method are registers a middleware for methods in gRPC client.

See See interceptor

(c *GrpcClient) AddInterceptors(interceptors …grpc.DialOption)

• interceptors: …grpc.DialOption - interceptor functions (Stream or Unary use grpc.WithUnaryInterceptor() or grpc.WithStreamInterceptor() for inflate in grpc.ServerOption)

AddFilterParams

AddFilterParams method are adds filter parameters (with the same name as they defined)

(c *GrpcClient) AddFilterParams(params *cdata.StringValueMap, filter *cdata.FilterParams) *cdata.StringValueMap

• params: *cdata.StringValueMap - invocation parameters.
• filter: *cdata.FilterParams - (optional) filter parameters.
• returns: *cdata.StringValueMap - invocation parameters with added filter parameters.

AddFilterParams

AddFilterParams method are adds filter parameters (with the same name as they defined)

(c *GrpcClient) AddPagingParams(params *cdata.StringValueMap, paging *cdata.PagingParams) *cdata.StringValueMap

• params: *cdata.StringValueMap - invocation parameters.
• filter: *cdata.PagingParams - (optional) filter parameters.
• returns: *cdata.StringValueMap - invocation parameters with added filter parameters.

Call

Calls a remote method via GRPC protocol.

(c *GrpcClient) Call(method string, correlationId string, request interface{}, response interface{}) error

• method: string - name of the calling method
• client: interface{} - current client
• request: interface{} - (optional) request object.
• returns: error - error or nil no errors occured.

CallWithContext

CallWithContext method are calls a remote method via gRPC protocol.

(c *GrpcClient) CallWithContext(ctx context.Context, correlationId string, method string, request interface{}, response interface{}) error

• ctx: context.Context - operation context.
• correlationId: string - transaction id to trace execution through call chain.
• method: string - gRPC method name
• request: interface{} - request query parameters.
• response: interface{} - response body object.
• returns: error - error or nil no errors occured.

Close

Closes the component and frees used resources.

(c *GrpcClient) Close(ctx context.Context, correlationId string) error

• ctx: context.Context - operation context.
• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• returns: error - error or nil no errors occured.

Configure

Configures the component by passing its configuration parameters.

(c *GrpcClient) Configure(ctx context.Context, config *cconf.ConfigParams)

• ctx: context.Context - operation context.
• config: *cconf.ConfigParams - configuration parameters to be set.

Instrument

Adds instrumentation to log calls and measures call time. It returns a CounterTiming object that is used to end the time measurement.

(c *GrpcClient) Instrument(ctx context.Context, correlationId string, name string) *ccount.CounterTiming

• ctx: context.Context - operation context.
• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• name: string - method name.
• returns: *ccount.CounterTiming - CounterTiming object used to end the time measurement.

InstrumentError

Adds instrumentation to error handling.

(c *GrpcClient) InstrumentError(ctx context.Context, correlationId string, name string, inErr error, inRes interface{}) (result interface{}, err error)

• ctx: context.Context - operation context.
• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• name: string - method name.
• inErr: error - occured error
• inRes: interface{} - (optional) an execution result
• returns: (result interface{}, err error) - input result and error.

IsOpen

Checks if the component is open.

(c *GrpcClient) IsOpen() bool

• returns: bool - Returns True if the component is open and False otherwise.

open

Opens the component.

(c *GrpcClient) Open(ctx context.Context, correlationId string) error

• ctx: context.Context - operation context.
• correlationId: string - (optional) transaction id used to trace execution through the call chain.
• returns: error - error or nil no errors occured.

SetReferences

Sets references to dependent components.

(c *GrpcClient) SetReferences(ctx context.Context, references cref.IReferences)

• ctx: context.Context - operation context.
• references: cref.IReferences - references to locate the component dependencies.

Examples

type MyGrpcClient struct{
	*GrpcClient
}

func  (c *MyGrpcClient) GetData(ctx context.Context, correlationId string, id string) (res any, err error) {
	req := &testproto.MyDataIdRequest{
	    CorrelationId: correlationId,
	    mydataId:       id,
	}
	reply := new(testproto.MyData)
	err = c.Call("get_mydata_by_id", correlationId, req, reply)
	c.Instrument(correlationId, "mydata.get_one_by_id")
	if err != nil {
	    return nil, err
	}

	result = toMyData(reply)
	if result != nil && result.Id == "" && result.Key == "" {
	    result = nil
	}

	return result, nil
}

var client = NewMyGrpcClient();
client.Configure(ctx, NewConfigParamsFromTuples(
    "connection.protocol", "http",
    "connection.host", "localhost",
    "connection.port", 8080,
));

result, err := client.GetData(ctx, "123", "1")
...