API Common

Features

• Logger class that logs to console in dev mode and to File in non development mode
• Middlewares for
  • Request response logging
  • Error handler for uncaught exceptions, 400 bad request and explicitly set 500.
  • Correlation ID setting middleware
  • JWT unpacking
• Error Formatters

  const Fmt =  require('api-common').Formatter;
  const err = new Error('Any error you want to log');
  const reporter = 'Place from which this log message is emitted';
  const appName = 'sample-app';
  Fmt.buildLogMessage(req, res, err, appName, reporter);

• Ping and app info endpoints

Steps

1. Install the package

   npm i api-common --save

2. Using the logger

   'use strict';
    
   // Get the logger instance configured with provided config
   const logger = require('api-common').getLogger('fullPathToLogFile');
    
   // export it so that your rest of the application can simply consume
   // this preconfigured logger.
   module.exports = logger;

3. Using the middleware

   'use strict';
    
   const SwaggerExpressMiddleware = require('swagger-express-mw');
   const SwaggerUIMiddleware = require('swagger-ui-middleware');
    
   // A very good middleware that works out of the box, please use it.
   const ResponseTimer = require('response-time');
    
   // STEP 1: Load the appconfig.json that has the logging config in it.
   const appConfig = require('./../config/appconfig.json');
    
   // STEP 2: Initialize the middleware
   const CustomMiddleware = require('api-common').Middleware.init(appConfig.appName);
   /*
     The app name can be provided any way you can.
   */
    
   const port = process.env.PORT || appConfig.port;
   const config = {
       appRoot: "./src" // required config
   };
   let app = require('express')();
    
   // STEP: 3 Start wiring up the middleware [Order is important]
   app.use(CustomMiddleware.CorrelationIdMiddleware);
   app.use(CustomMiddleware.RequestResponseMiddleware);
   app.use(ResponseTimer());
    
   SwaggerUIMiddleware.hostUI(app,{
       path: appConfig.swaggerUiPath,
       overrides: "./src/swagger"
   });
    
   SwaggerExpressMiddleware.create(config, function (err, swaggerExpress) {
       if (err) {
           throw err;
       }
    
       // install middleware
       swaggerExpress.register(app);
    
       // Wire error handlers after this line
    
       //STEP:4 ALWAYS put this middleware in the end. It ends request pipe.
       app.use(CustomMiddleware.ErrorLoggingMiddleware);
   });
    
    
   module.exports = app; // for testing
    
   app.listen(port);

4. Using the logger from within Sequelize model initializers

   'use strict';
   const path = require('path');
   const dbconf = require('../../../config/dbconfig');
   // here we use the logger wrapper from #2
   const logger = require('../helpers/Logger');
    
   let Sequelize = require('sequelize');
   dbconf.CONNECTION_CONFIG.logging = function(sqlInfo){
       logger.debug({ sql: sqlInfo ,from: path.basename(__filename) });
   };

5. Using the ping and app info endpoints

   Pass in the express app and the configuration you want to show in the app info endpoint.

   require('api-common').StatusInformation.initializeStatusEndpoints(app, { example: 'configuration' });

6. Important note when using within Swagger projects.

   • in ./config/default.yaml if it looks like

     # pipe for all swagger-node controllers 
         swagger_controllers:
           - onError: json_error_handler
           - cors
           - swagger_security
           - _swagger_validate
           - express_compatibility
           - _router

   • Make sure you remove the onError key. It interferes with our error handler.

     # pipe for all swagger-node controllers 
         swagger_controllers:
           - cors
           - swagger_security
           - _swagger_validate
           - express_compatibility
           - _router