@bbc/http-transport/lib/middleware/logger.js

A flexible, modular REST client built for ease-of-use and resilience.

'use strict';

function isRetry(ctx) {
  const attempts = ctx.retryAttempts || [];
  return attempts.length > 0;
}

function isCriticalError(ctx) {
  return ctx.res.statusCode >= 500;
}

function hasElapsedTime(ctx) {
  return ctx.res?.elapsedTime !== undefined;
}

function getBaseMessage(ctx) {
  return `${ctx.req.getMethod()} ${ctx.req.getUrl()} ${ctx.res.statusCode}`;
}

function createRequestMessage(ctx) {
  const res = ctx.res;

  const message = getBaseMessage(ctx);
  if (hasElapsedTime(ctx)) return `${message} ${res.elapsedTime} ms`;

  return message;
}

function createRetryMessage(ctx) {
  const message = `Attempt ${ctx.retryAttempts.length} ${getBaseMessage(ctx)}`;
  if (hasElapsedTime(ctx)) return `${message} ${ctx.res.elapsedTime} ms`;

  return message;
}

module.exports = (customLogger) => {
  const logger = customLogger || console;

  return async (ctx, next) => {
    await next();

    if (isRetry(ctx) && isCriticalError(ctx)) {
      return logger.warn(createRetryMessage(ctx));
    }
    logger.info(createRequestMessage(ctx));
  };
};