apiHandler.js

'use strict';

const co         = require('co');
const log        = require('./log');
const reqContext = require('./requestContext');

function setRequestContext (event, context) {
  // extracts correlation IDs, User-Agent, etc. from HTTP headers
  // and stores them in the requestContext
};

function OK (result) { 
  // return 200 response
};

function createApiHandler (f) {  
  return co.wrap(function* (event, context, cb) {
    console.log(JSON.stringify(event));

    reqContext.clearAll();

    try {
      setRequestContext(event, context);
    } catch (err) {
      log.warn(`couldn't set current request context: ${err}`, err.stack);
    }

    try {  
      let result = yield Promise.resolve(f(event, context));
      result = result || {};

      log.info('SUCCESS', JSON.stringify(result));
      cb(null, OK(result));
    } catch (err) {
      log.error("Failed to process request", err);
      cb(err);
    }
  });
}

module.exports = createApiHandler;