@usvc/component-request NPM

`@usvc/component-request`

Request module with zipkin instrumentation based on node-fetch.

Scope

create a Zipkin instrumented request object
fallback to normal request if no tracer is provided

Installation

npm i @usvc/component-request
# OR
yarn add @usvc/component-request

Usage

const {createRequest} = require('@usvc/component-request');
// OR
import {createRequest} from '@usvc/component-request';

Basic

// require as ^
createRequest();

Full Configuration

// require as ^
// with your own tracer:
const tracer = require('./tracer');
// OR if you're using @usvc/tracer:
const {createTracer} = require('@usvc/tracer');
const tracerInstance = createTracer({
  url: 'http://zipkin:9411', // for example only
});
createRequest({
  format: 'json',
  tracer: tracerInstance.getTracer()
});

API Documentaiton

`.createRequest(:options)`

Returns a request-like function. The :options parameter is an object that can accept the following keys:

Key	Defaults To	Description
`format`	`"json"`	Decides the format of the response. Possible values are `"buffer"`, `"json"`, and `"text"`.
`tracer`	`null`	Defines the tracer we should use. When left as `null`, no distributed tracing will be made available.

When a tracer is specified in the parameters, the function signature of the returned request will be:

export type RequestWithTracing = (
  remoteServerName: string,
  url: string,
  options: object,
) => RequestPromise<object>;

When no tracer is specified, the function signature will lack the :remoteServiceName parameter and resemble a standard fetch operation:

export type RequestWithoutTracing = (
  url: string,
  options: object,
) => RequestPromise<object>;

The UsvcResponse object returned by the Promise has the following schema:

export interface UsvcResponse {
  body: object; // response body
  headers: object; // response headers
  status: number; // HTTP status code
  statusText: string; // HTTP status text
  url: string; // request URL
}