app.js

//-------------------------------------------------------------------------------
// Copyright IBM Corp. 2016
//
// Licensed under the Apache License, Version 2.0 (the 'License');
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an 'AS IS' BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//-------------------------------------------------------------------------------

'use strict';

const consts = require('./lib/consts.js');
const cfenv = require('cfenv');
const express = require('express');
const bodyParser = require('body-parser');
const passport = require('passport');

// to enable debugging, set environment variable DEBUG to slack-about-service or *
const debug = require('debug')(consts.appPrefix);

var R = require('./lib/replicate.js');
const mutil = require('./lib/util.js');
const security = require('./lib/security.js');

/*
 * 
 * Environment variable dependencies:
 *  - SOURCE_COUCH_DB_URL: https://$USERNAME:$PASSWORD@$REMOTE_USERNAME.cloudant.com/$SOURCE_DATABASE_NAME
 *  - TARGET_COUCH_DB_URL: https://$USERNAME:$PASSWORD@$REMOTE_USERNAME.cloudant.com/$TARGET_DATABASE_NAME
 *  - RESTART (optional, default is false): if true, the change feed will process all document changes since the database was created; otherwise 
 *      only new document changes will be processed
 *  - TRANSFORM_FUNCTION (optional, default no transformation): file containing the Javascript routine to be used to transform documents
 *  - SERVER_FILTER (optional, no default): name of an existing filter in the source database, expressed as "$DESIGN_DOC_NAME/$FILTER_NAME"
 *  - CLIENT_FILTER (optional, no default): name of a file in the application directory containing a filter function: $PATH_TO/$FILTER_FUNCTION_FILE_NAME
 *  - HIDE_CONSOLE (optional, default false): disables all API endpoints
 *  - DEBUG (optional): if set to * or $APP_PREFIX:$MODULE, debug information is added to the log
 */

	debug(consts.appPrefix + ': debug is enabled.');

/*
 * Verify that the application was properly configured 
 */

if((! process.env.SOURCE_COUCH_DB_URL) || (!process.env.TARGET_COUCH_DB_URL)) {
    console.error('Environment variables SOURCE_COUCH_DB_URL or TARGET_COUCH_DB_URL is not set.');
    console.error('SOURCE_COUCH_DB_URL https://$USERNAME:$PASSWORD@$REMOTE_USERNAME.cloudant.com/$SOURCE_DATABASE_NAME');
    console.error('TARGET_COUCH_DB_URL https://$USERNAME:$PASSWORD@$REMOTE_USERNAME.cloudant.com/$TARGET_DATABASE_NAME');
    process.exit(1);
}

var r = new R(mutil.splitUrl(process.env.SOURCE_COUCH_DB_URL), 
			        mutil.splitUrl(process.env.TARGET_COUCH_DB_URL),
              mutil.isTrue(process.env.RESTART));

r.init(function(err) {

  if(err) {
    console.error('Error. Service initialization failed: ' + err);
    console.error('Check the log file for additional information.');
    console.error('The service is stopping.');
    process.exit(1);
  }

  var appEnv = null;

  try {
    appEnv = cfenv.getAppEnv({vcap: {services: require('./vcap_services.json')}});
  }
  catch(ex) {
    appEnv = cfenv.getAppEnv();
  }

  var app = express();
  app.use(bodyParser.urlencoded({extended: false}));

  console.log('Console security is set to: "' + security.strategyName + '"');
  passport.use(security.strategy);

  if(! process.env.HIDE_CONSOLE) {
    // replication status endpoint
    app.get('/status', 
            passport.authenticate(security.strategyName, {session:false}),
            function(req,res) {
              r.getDetailedStatus(function(err, status) {
                console.log('Service status:' + JSON.stringify(status, null, 1));      
                res.status(200).json(status);    
              });
            });   
  }

  // start server on the specified port and binding host
  app.listen(appEnv.port, '0.0.0.0', function() {
      console.log('Server starting on ' + appEnv.url);
      if(! process.env.HIDE_CONSOLE) {
        console.log('Status information is made available at ' + appEnv.url + '/status');
        console.log('To disable status output, set environment variable HIDE_CONSOLE to true and restart the application.');
      }
  });

});

// send sample application deployment tracking request to https://github.com/IBM-Bluemix/cf-deployment-tracker-service
require('cf-deployment-tracker-client').track();