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.

GrpcClient(String clientName)

• clientName: String - client’s name.

Fields

Instance methods

addFilterParams

AddFilterParams method are adds filter parameters (with the same name as they defined) to invocation parameter map.

StringValueMap addFilterParams(StringValueMap? params, FilterParams? filter)

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

addPagingParams

AddPagingParams method are adds paging parameters (skip, take, total) to invocation parameter map.

StringValueMap addPagingParams(StringValueMap? params, PagingParams? paging)

• params: StringValueMap? - invocation parameters.
• paging: PagingParams? - (optional) paging parameters
• returns: StringValueMap - invocation parameters with added paging parameters.

call

Calls a remote method via gRPC protocol.

grpc.ResponseFuture<R>call<Q extends GeneratedMessage, R extends GeneratedMessage>(String method, String? correlationId, Q request, {grpc.CallOptions? options})

• method: String - name of the calling method
• correlationId: String? - current client
• request: Q - (optional) request object.
• options: grpc.CallOptions? - (optional) call options
• returns: grpc.ResponseFuture<R> - (optional) Future that receives result object or error.

close

Closes the component and frees used resources.

@override

Future close(String? correlationId)

• correlationId: String? - (optional) transaction id used to trace execution through the call chain.

configure

Configures the component by passing its configuration parameters.

@override

void configure(ConfigParams config)

• config: ConfigParams - configuration parameters to be set.

instrument

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

InstrumentTiming instrument(String? correlationId, String name)

• correlationId: String? - (optional) transaction id used to trace execution through the call chain.
• name: String - method name.
• returns: InstrumentTiming - CounterTiming object used to end the time measurement.

isOpen

Checks if the component is open.

@override

bool isOpen()

• returns: bool - true if the component is open and false otherwise.

open

Opens the component.

@override

Future open(String? correlationId)

• correlationId: String? - (optional) transaction id used to trace execution through the call chain.

setReferences

Sets references to dependent components.

@override

void setReferences(IReferences references)

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

Examples

class MyGrpcClient extends GrpcClient implements IMyClient {
   ...
   Future<MyData> getData(String? correlationId, string id) async {
       var counter_timing = this.instrument(correlationId, 'myclient.get_data');
       var request = MyDataRequest();
       request.id = id;
       var response = await call<MydataRequest,MyDataResponse>('get_data', correlationId, request)
       counter_timing.endTiming();
       MyData item;
       ///... convert MyDataResponse to MyData
       return item;
   }
   ...
}
var client = MyGrpcClient();
client.configure(ConfigParams.fromTuples([
    'connection.protocol', 'http',
    'connection.host', 'localhost',
    'connection.port', 8080
]));

var item = await client.getData('123', '1')
  ...