run.js

/* jshint node: true */
"use strict";

var carelink = require('./carelink'),
  filter = require('./filter'),
  logger = require('./logger'),
  nightscout = require('./nightscout'),
  transform = require('./transform');

function readEnv(key, defaultVal) {
  var val = process.env[key] ||
    process.env[key.toLowerCase()] ||
    // Azure prefixes environment variables with this
    process.env['CUSTOMCONNSTR_' + key] ||
    process.env['CUSTOMCONNSTR_' + key.toLowerCase()];
  return val !== undefined ? val : defaultVal;
}

var config = {
  username: readEnv('CARELINK_USERNAME'),
  password: readEnv('CARELINK_PASSWORD'),
  nsHost: readEnv('WEBSITE_HOSTNAME'),
  nsBaseUrl: readEnv('NS'),
  nsSecret: readEnv('API_SECRET'),
  interval: parseInt(readEnv('CARELINK_REQUEST_INTERVAL', 60 * 1000), 10),
  sgvLimit: parseInt(readEnv('CARELINK_SGV_LIMIT', 24), 10),
  maxRetryDuration: parseInt(readEnv('CARELINK_MAX_RETRY_DURATION', carelink.defaultMaxRetryDuration), 10),
  verbose: !readEnv('CARELINK_QUIET')
};

if (!config.username) {
  throw new Error('Missing CareLink username');
} else if(!config.password) {
  throw new Error('Missing CareLink password');
}

var client = carelink.Client({
  username: config.username,
  password: config.password,
  maxRetryDuration: config.maxRetryDuration
});
var entriesUrl = (config.nsBaseUrl ? config.nsBaseUrl : 'https://' + config.nsHost) + '/api/v1/entries.json';
var devicestatusUrl = (config.nsBaseUrl ? config.nsBaseUrl : 'https://' + config.nsHost) + '/api/v1/devicestatus.json';

logger.setVerbose(config.verbose);

var filterSgvs = filter.makeRecencyFilter(function(item) {
  return item['date'];
});

var filterDeviceStatus = filter.makeRecencyFilter(function(item) {
  return new Date(item['created_at']).getTime();
});

function uploadMaybe(items, endpoint, callback) {
  if (items.length === 0) {
    logger.log('No new items for ' + endpoint);
    callback();
  } else {
    nightscout.upload(items, endpoint, config.nsSecret, function(err, response) {
      if (err) {
        // Continue gathering data from CareLink even if Nightscout can't be reached
        console.log(err);
      }
      callback();
    });
  }
}

(function requestLoop() {
  client.fetch(function(err, data) {
    if (err) {
      throw new Error(err);
    } else {
      var transformed = transform(data, config.sgvLimit);

      // Because of Nightscout's upsert semantics and the fact that CareLink provides trend
      // data only for the most recent sgv, we need to filter out sgvs we've already sent.
      // Otherwise we'll overwrite existing sgv entries and remove their trend data.
      var newSgvs = filterSgvs(transformed.entries);

      // Nightscout's entries collection upserts based on date, but the devicestatus collection
      // does not do the same for created_at, so we need to de-dupe them here.
      var newDeviceStatuses = filterDeviceStatus(transformed.devicestatus);

      uploadMaybe(newSgvs, entriesUrl, function() {
        uploadMaybe(newDeviceStatuses, devicestatusUrl, function() {
          setTimeout(requestLoop, config.interval);
        });
      });
    }
  });
})();