DirectClient<T>

Implements: IConfigurable, IReferenceable, IOpenable

Description

The DirectClientclass allows you to create clients that call a controller directly in the same memory space.

Important points

• It is used when multiple microservices are deployed in a single container (monolyth) and communication between them can be done by direct calls rather than through the network.

Configuration parameters

• dependencies:
  • controller: override controller descriptor

References

• *:logger:*:*:1.0 - (optional) ILogger components to pass log messages
• *:counters:*:*:1.0 - (optional) ICounters components to pass collected measurements
• *:traces:*:*:1.0 - (optional) ITracer components to record traces
• *:discovery:*:*:1.0 - (optional) IDiscovery services to resolve a connection

Constructors

Creates a new instance of the client.

DirectClient()

Fields

Instance methods

close

Closes a component and frees used resources.

@override

Future close(IContext? context)

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

configure

Configures component by passing configuration parameters.

@override void configure(ConfigParams config)

• 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.

InstrumentTiming instrument(IContext? contextd, String name)

• context: IContext - (optional) a context to trace execution through a call chain.
• name: String - method name.
• returns: InstrumentTiming - InstrumentTiming 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(IContext? context)

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

setReferences

Sets references to dependent components.

@override

void setReferences(IReferences references)

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

Examples

class MyDirectClient extends DirectClient<IMyController> implements IMyClient {
    MyDirectClient(): super() {
      dependencyResolver.put('controller', Descriptor(
          "mygroup", "controller", "*", "*", "*"));
    }
    ...
    Future<MyData> getData(IContext? context, String id) async {
      var counter_timing = instrument(contextd, 'myclient.get_data');
      try {
      var result = await controller.getData(context, id)
      counter_timing.endTiming();
      return result;
      } catch (err){
         counter_timing.endTiming();
         instrumentError(context, 'myclient.get_data', err, reerror=true);
      });
    }
    ...
}

var client = MyDirectClient();
client.setReferences(References.fromTuples([
     Descriptor("mygroup","controller","default","default","1.0"), controller
]));

var result = await client.getData("123", "1")
  ...