logger.ts

import Router from 'koa-router';
import pinoLogger from 'pino-multi-stream';
const cloudwatch = require('pino-cloudwatch'); //tslint:disable-line
import { config } from './config';

export interface ILog {
  data?: any;
  host: string;
  method: string;
  query: string;
  remoteAddress: string;
  status: number;
  url: string;
  userAgent: string;
  userId?: string;
}

type ErrorObj = {
  err: Partial<Error>;
};

export interface ILogger {
  info(obj: object | string, ...params: any[]): void;
  warn(obj: object | string, ...params: any[]): void;
  error(obj: Error | ErrorObj | string, ...params: any[]): void;
  child(options: { module: string; userId?: string }): ILogger;
}

export const loggerMiddleware = (externalLogger: ILogger) => async (
  ctx: Router.RouterContext<any, { logger: ILogger }>,
  next: () => Promise<any>,
) => {
  const logger = externalLogger;

  const data: Partial<ILog> = {
    status: ctx.status,
    method: ctx.method,
    url: ctx.url,
    query: ctx.query,
  };
  try {
    ctx.logger = logger;
    await next();
    data.status = ctx.status;
  } catch (e) {
    logger.error(e);
    data.status = e.status;
  }
  logger.info({
    msg: 'Processed request',
    ...data,
    userId: ctx.state && ctx.state.user ? ctx.state.user.id : undefined,
  });
};

export function createDefaultLogger() {
  const streams = [{ stream: process.stdout }];
  const { accessKeyId, secretAccessKey, region } = config.aws;
  if (process.env.NODE_ENV === 'production' && accessKeyId && secretAccessKey) {
    const writeStream = cloudwatch({
      interval: 2000,
      aws_access_key_id: accessKeyId,
      aws_secret_access_key: secretAccessKey,
      aws_region: region,
      group: '/app/rsschool-api',
    });
    streams.push(writeStream);
  }
  return pinoLogger({ streams, base: null }) as ILogger;
}