GrpcClient

Abstract client that calls remote endpoints using the GRPC protocol.

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 constructor(clientTypeOrPath: any, clientName?: string, packageOptions?: any)

  • clientTypeOrPath: any - TODO: add description
  • clientName: string - client’s name.
  • packageOptions: any - TODO: add description

Fields

_client

The GRPC client.

protected _client: any

_connectionResolver

The connection resolver.

protected _connectionResolver: HttpConnectionResolver

_logger

The logger.

protected _logger: CompositeLogger()

_counters

The performance counters.

protected _counters: CompositeCounters()

_options

The configuration options.

protected _options: ConfigParams()

_connectTimeout

The connection timeout in milliseconds.

protected _connectTimeout: number = 100000

_timeout

The invocation timeout in milliseconds.

protected _timeout: number = 100000

_uri

The remote service uri which is calculated on openning.

protected _uri: string

_tracer

The tracer.

protected _tracer: CompositeTracer = CompositeTracer()

Instance methods

call

Calls a remote method via GRPC protocol.

protected call(method: string, correlationId?: string, request: any = {}): Promise<any>

  • method: string - name of the calling method
  • correlationId: any - (optional) transaction id to trace execution through call chain.
  • request: any - (optional) request object.
  • returns: Promise<any> - (optional) feature that receives the result object or error.

close

Closes the component and frees used resources.

public close(correlationId: string): Promise<void>

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

configure

Configures the component by passing its configuration parameters.

public configure(config: ConfigParams): void

  • 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 instrument(correlationId: string, name: string): InstrumentTiming

  • 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.

public isOpen(): boolean

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

open

Opens the component.

public open(correlationId: string): Promise<void>

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

setReferences

Sets references to dependent components.

public setReferences(references: IReferences): void

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

Examples

class MyGrpcClient extends GrpcClient implements IMyClient {
    ...
    public getData(correlationId: string, id: string): Promise<MyData> {
   
        let timing = this.instrument(correlationId, 'myclient.get_data');
        try {
           return await this.call("get_data", correlationId, { id: id });
        } catch (err) {
            timing.endFailure(err);
            throw err;
        } finally {
            timing.endSuccess();
        }
    }       
   ...
}

let client = new MyGrpcClient();
client.configure(ConfigParams.fromTuples(
    "connection.protocol", "http",
    "connection.host", "localhost",
    "connection.port", 8080
));

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