gistfile1.js

var pg = require('pg');
var request = require('request');
var Promise = require('bluebird'); // version 2.0!

// pg interface is a bit awkward to promisify
var connect = Promise.promisify(pg.connect, pg);
pg.connect = function (connString) {
    return connect(connString).spread(function (client, done) {
        client.done = done;
        Promise.promisify(client, { suffix: '$' });
    });
}

var request$ = Promise.promisify(request);

 
function getUrl(location) {
	return 'https://maps.googleapis.com/maps/api/geocode/json?address=' + location.address + ', ' + location.city + ', ' + location.state + ' ' + location.zip_code;
}
 
var count = 0;

pg.connect(connString)
.then(function (client) {
    return client.query$('SELECT id, address, city, state, zip_code FROM companies WHERE pos IS NULL')
    .reduce(function (ignore, company) { // using reduce to execute requests only one at a time
        return request(getUrl(company))
        .spread(function (res, body) {
            var location = body.results[0].geometry.location;
            return client.query$(
                'UPDATE companies SET pos = point($1, $2) WHERE id = $3',
                [ location.lng, location.lat, company.id ]
            );
        })
        .catch(function (err) {
            console.error("Error fetching data for %s: %s", company, err);
        });
    });
}).catch(function (err) {
    console.error("Error: %s", err);
});