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.

public public GrpcClient(io.grpc.ServiceDescriptor serviceDescriptor)

Fields

Instance methods

call

Calls a remote method via GRPC protocol.

protected <TRequest, TResponse> TResponse call(String methodName, IContext context, TRequest request)

• methodName: string - name of the calling method
• context: IContext - (optional) a context to trace execution through a call chain.
• request: TRequest - (optional) request object.
• returns: <TRequest, TResponse> TResponse - (optional) feature that receives the result object or error.

close

Closes the component and frees used resources.

public void close(IContext context) throws ApplicationException

• context: IContext - (optional) a context to trace execution through a call chain.

configure

Configures the component by passing its configuration parameters.

public void configure(ConfigParams config) throws ConfigException

• config: 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.

protected InstrumentTiming instrument(IContext context, String name)

• context: IContext - (optional) a context to trace execution through a call chain.
• name: String - method name.
• returns: InstrumentTiming - CounterTiming object used to end the time measurement.

isOpen

Checks if the component is open.

public boolean isOpen()

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

open

Opens the component.

public void open(IContext context) throws ApplicationException

• context: IContext - (optional) a context to trace execution through a call chain.

setReferences

Sets references to dependent components.

public void setReferences(IReferences references) throws ReferenceException, ConfigException

• references: IReferences - references to locate the component dependencies.

Examples

{@code
  class MyGrpcClient extends GrpcClient implements IMyClient {
 
      public MyCommandableGrpcClient() {
          super(myGrpcService.getServiceDescriptor());
      }
 
      // ...
 
      @Override
      MyData getData(IContext context, String id) {
          var request = GetDataRequest.newBuilder();
          request.setid(id);
 
          this.instrument(context, "myclient.get_data");
 
          MyData result = this.call("get_data",
                  context,
                  request.build()
          );
 
          if (result != null && Objects.equals(result.getId(), ""))
              return null;
 
          return new MyData(result.getId(), result.getKey(), result.getContent());
      }
 
      public static void main(String[] args) throws ConfigException {
          var client = new MyCommandableGrpcClient();
          client.configure(ConfigParams.fromTuples(
                  "connection.protocol", "http",
                  "connection.host", "localhost",
                  "connection.port", 8080
          ));
 
          var result = client.getData("123", "1");
      }
  }
  }