Trying to connect my node.js to Heroku PostgreSQL database. Following Heroku Postgres tutorial

Question

I'm following these two Heroku tutorials:

https://devcenter.heroku.com/articles/getting-started-with-nodejs

and

https://devcenter.heroku.com/articles/heroku-postgresql

I have the 'hello world' app working. But I am getting an error when I add the node.js code to connect to postgreSQL.

My package.json

{
  "name": "node-example",
  "version": "0.0.1",
  "dependencies": {
    "pg": "2.x",
    "express": "3.1.x"
  },
  "engines": {
    "node": "0.10.x",
    "npm": "1.2.x"
  }
}

My web.js

var express = require("express");
var app = express();
app.use(express.logger());

app.get('/', function(request, response) {
  response.send('Hello World!');
});

var port = process.env.PORT || 5000;
app.listen(port, function() {
  console.log("Listening on " + port);
});

var pg = require('pg');

pg.connect(process.env.DATABASE_URL, function(err, client, done) {
  client.query('SELECT * FROM your_table', function(err, result) {
    done();
    if(err) return console.error(err);
    console.log(result.rows);
  });
});

My Heroku postgres database is working well and I can connect to it directly with

heroku pg:psql

Here are my logs:

2013-09-29T13:13:34.777156+00:00 heroku[web.1]: State changed from starting to up
2013-09-29T13:13:34.784018+00:00 app[web.1]: 
2013-09-29T13:13:34.787193+00:00 app[web.1]: events.js:72
2013-09-29T13:13:34.787469+00:00 app[web.1]:         throw er; // Unhandled 'error' event
2013-09-29T13:13:34.787642+00:00 app[web.1]:               ^
2013-09-29T13:13:34.790791+00:00 app[web.1]: error: relation "junk" does not exist
2013-09-29T13:13:34.790791+00:00 app[web.1]:     at Connection.parseE (/app/node_modules/pg/lib/connection.js:546:11)
2013-09-29T13:13:34.790791+00:00 app[web.1]:     at Connection.parseMessage (/app/node_modules/pg/lib/connection.js:375:17)
2013-09-29T13:13:34.790791+00:00 app[web.1]:     at null.<anonymous> (/app/node_modules/pg/lib/connection.js:92:20)
2013-09-29T13:13:34.790791+00:00 app[web.1]:     at Socket.EventEmitter.emit (events.js:95:17)
2013-09-29T13:13:34.790791+00:00 app[web.1]:     at Socket.<anonymous> (_stream_readable.js:746:14)
2013-09-29T13:13:34.790791+00:00 app[web.1]:     at Socket.EventEmitter.emit (events.js:92:17)
2013-09-29T13:13:34.790791+00:00 app[web.1]:     at emitReadable_ (_stream_readable.js:408:10)
2013-09-29T13:13:34.790791+00:00 app[web.1]:     at emitReadable (_stream_readable.js:404:5)
2013-09-29T13:13:34.790791+00:00 app[web.1]:     at readableAddChunk (_stream_readable.js:165:9)
2013-09-29T13:13:34.790968+00:00 app[web.1]:     at Socket.Readable.push (_stream_readable.js:127:10)
2013-09-29T13:13:36.511975+00:00 heroku[web.1]: Process exited with status 8
2013-09-29T13:13:36.527681+00:00 heroku[web.1]: State changed from up to crashed
2013-09-29T13:21:22+00:00 heroku[slug-compiler]: Slug compilation started
2013-09-29T13:21:38+00:00 heroku[slug-compiler]: Slug compilation finished
2013-09-29T13:21:39.239935+00:00 heroku[web.1]: State changed from crashed to starting
2013-09-29T13:21:40.589773+00:00 heroku[web.1]: Starting process with command `node web.js`
2013-09-29T13:21:41.345806+00:00 app[web.1]: Listening on 20977
2013-09-29T13:21:41.368323+00:00 app[web.1]: { [error: relation "your_table" does not exist]
2013-09-29T13:21:41.368323+00:00 app[web.1]:   length: 101,
2013-09-29T13:21:41.368323+00:00 app[web.1]:   detail: undefined,
2013-09-29T13:21:41.368323+00:00 app[web.1]:   severity: 'ERROR',
2013-09-29T13:21:41.368323+00:00 app[web.1]:   hint: undefined,
2013-09-29T13:21:41.368323+00:00 app[web.1]:   position: '15',
2013-09-29T13:21:41.368323+00:00 app[web.1]:   code: '42P01',
2013-09-29T13:21:41.368323+00:00 app[web.1]:   name: 'error',
2013-09-29T13:21:41.368323+00:00 app[web.1]:   internalPosition: undefined,
2013-09-29T13:21:41.368512+00:00 app[web.1]:   where: undefined,
2013-09-29T13:21:41.368512+00:00 app[web.1]:   file: 'parse_relation.c',
2013-09-29T13:21:41.368512+00:00 app[web.1]:   line: '864',
2013-09-29T13:21:41.368323+00:00 app[web.1]:   internalQuery: undefined,
2013-09-29T13:21:41.368512+00:00 app[web.1]:   routine: 'parserOpenTable' }
2013-09-29T13:21:41.938926+00:00 heroku[web.1]: State changed from starting to up
2013-09-29T13:21:38.600520+00:00 heroku[api]: Deploy 95a0a35 by *********@gmail.com
2013-09-29T13:21:38.625733+00:00 heroku[api]: Release v17 created by *******@gmail.com
2013-09-29T13:22:08.383050+00:00 heroku[router]: at=info method=GET path=/ host=pure-lake-7106.herokuapp.com fwd="58.7.243.156" dyno=web.1 connect=3ms service=6ms status=200 bytes=12
2013-09-29T13:22:08.383327+00:00 app[web.1]: - - - [Sun, 29 Sep 2013 13:22:08 GMT] "GET / HTTP/1.1" 200 12 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/28.0.1500.71 Chrome/28.0.1500.71 Safari/537.36"
2013-09-29T13:22:10.046808+00:00 app[web.1]: - - - [Sun, 29 Sep 2013 13:22:10 GMT] "GET /favicon.ico HTTP/1.1" 404 - "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/28.0.1500.71 Chrome/28.0.1500.71 Safari/537.36"
2013-09-29T13:22:10.049179+00:00 heroku[router]: at=info method=GET path=/favicon.ico host=pure-lake-7106.herokuapp.com fwd="58.7.243.156" dyno=web.1 connect=1ms service=3ms status=404 bytes=34
2013-09-29T13:29:40+00:00 heroku[slug-compiler]: Slug compilation started
2013-09-29T13:30:07.484077+00:00 heroku[api]: Deploy a2cc795 by [email protected]
2013-09-29T13:30:07.515481+00:00 heroku[api]: Release v18 created by [email protected]
2013-09-29T13:30:07+00:00 heroku[slug-compiler]: Slug compilation finished
2013-09-29T13:30:08.016355+00:00 heroku[web.1]: State changed from up to starting
2013-09-29T13:30:10.017792+00:00 heroku[web.1]: Starting process with command `node web.js`
2013-09-29T13:30:10.099473+00:00 heroku[web.1]: Stopping all processes with SIGTERM
2013-09-29T13:30:11.008770+00:00 app[web.1]: Listening on 47344
2013-09-29T13:30:11.065531+00:00 app[web.1]:   name: 'error',
2013-09-29T13:30:11.065531+00:00 app[web.1]:   length: 101,
2013-09-29T13:30:11.065531+00:00 app[web.1]:   severity: 'ERROR',
2013-09-29T13:30:11.065531+00:00 app[web.1]:   code: '42P01',
2013-09-29T13:30:11.065531+00:00 app[web.1]:   detail: undefined,
2013-09-29T13:30:11.065531+00:00 app[web.1]:   position: '15',
2013-09-29T13:30:11.065531+00:00 app[web.1]: { [error: relation "your_table" does not exist]
2013-09-29T13:30:11.065531+00:00 app[web.1]:   internalPosition: undefined,
2013-09-29T13:30:11.065531+00:00 app[web.1]:   internalQuery: undefined,
2013-09-29T13:30:11.065840+00:00 app[web.1]:   where: undefined,
2013-09-29T13:30:11.065840+00:00 app[web.1]:   file: 'parse_relation.c',
2013-09-29T13:30:11.065840+00:00 app[web.1]:   line: '864',
2013-09-29T13:30:11.065840+00:00 app[web.1]:   routine: 'parserOpenTable' }
2013-09-29T13:30:11.065531+00:00 app[web.1]:   hint: undefined,
2013-09-29T13:30:11.482704+00:00 heroku[web.1]: State changed from starting to up
2013-09-29T13:30:11.651117+00:00 heroku[web.1]: Process exited with status 143
2013-09-29T13:30:17.729604+00:00 app[web.1]: - - - [Sun, 29 Sep 2013 13:30:17 GMT] "GET / HTTP/1.1" 200 12 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/28.0.1500.71 Chrome/28.0.1500.71 Safari/537.36"
2013-09-29T13:30:19.361615+00:00 heroku[router]: at=info method=GET path=/favicon.ico host=pure-lake-7106.herokuapp.com fwd="58.7.243.156" dyno=web.1 connect=1ms service=3ms status=404 bytes=34
2013-09-29T13:30:19.364457+00:00 app[web.1]: - - - [Sun, 29 Sep 2013 13:30:19 GMT] "GET /favicon.ico HTTP/1.1" 404 - "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/28.0.1500.71 Chrome/28.0.1500.71 Safari/537.36"
2013-09-29T13:30:17.728815+00:00 heroku[router]: at=info method=GET path=/ host=pure-lake-7106.herokuapp.com fwd="58.7.243.156" dyno=web.1 connect=1ms service=19ms status=200 bytes=12
2013-09-29T13:32:28+00:00 heroku[slug-compiler]: Slug compilation started
2013-09-29T13:32:43.338858+00:00 heroku[api]: Deploy d4cf2ba by [email protected]
2013-09-29T13:32:43.359317+00:00 heroku[api]: Release v19 created by [email protected]
2013-09-29T13:32:43+00:00 heroku[slug-compiler]: Slug compilation finished
2013-09-29T13:32:43.746015+00:00 heroku[web.1]: State changed from up to starting
2013-09-29T13:32:45.354842+00:00 heroku[web.1]: Starting process with command `node web.js`
2013-09-29T13:32:46.098651+00:00 app[web.1]: Listening on 37156
2013-09-29T13:32:47.127328+00:00 app[web.1]: { [error: relation "your_table" does not exist]
2013-09-29T13:32:47.127328+00:00 app[web.1]:   code: '42P01',
2013-09-29T13:32:47.127328+00:00 app[web.1]:   name: 'error',
2013-09-29T13:32:47.127328+00:00 app[web.1]:   length: 101,
2013-09-29T13:32:47.127328+00:00 app[web.1]:   hint: undefined,
2013-09-29T13:32:47.127328+00:00 app[web.1]:   position: '15',
2013-09-29T13:32:47.127328+00:00 app[web.1]:   severity: 'ERROR',
2013-09-29T13:32:47.127328+00:00 app[web.1]:   detail: undefined,
2013-09-29T13:32:47.127561+00:00 app[web.1]:   where: undefined,
2013-09-29T13:32:47.127561+00:00 app[web.1]:   routine: 'parserOpenTable' }
2013-09-29T13:32:47.127328+00:00 app[web.1]:   internalPosition: undefined,
2013-09-29T13:32:47.127328+00:00 app[web.1]:   internalQuery: undefined,
2013-09-29T13:32:47.127561+00:00 app[web.1]:   file: 'parse_relation.c',
2013-09-29T13:32:47.127561+00:00 app[web.1]:   line: '864',
2013-09-29T13:32:47.197293+00:00 heroku[web.1]: State changed from starting to up
2013-09-29T13:32:50.505267+00:00 heroku[web.1]: Stopping all processes with SIGTERM
2013-09-29T13:32:53.246120+00:00 heroku[web.1]: Process exited with status 143
2013-09-29T14:39:50.833246+00:00 heroku[web.1]: Idling
2013-09-29T14:39:52.828292+00:00 heroku[web.1]: Stopping all processes with SIGTERM
2013-09-29T14:39:54.545662+00:00 heroku[web.1]: Process exited with status 143
2013-09-29T14:39:54.559151+00:00 heroku[web.1]: State changed from up to down

I get this erroe when I do a foreman start

p$ foreman start
12:39:41 web.1  | started with pid 13983
12:39:41 web.1  | Listening on 5000
12:39:41 web.1  | /home/roland/github/heroku_app/web.js:18
12:39:41 web.1  |   client.query('SELECT * FROM your_table', function(err, result) {
12:39:41 web.1  |          ^
12:39:41 web.1  | TypeError: Cannot call method 'query' of null
12:39:41 web.1  |     at /home/roland/github/heroku_app/web.js:18:10
12:39:41 web.1  |     at /home/roland/github/heroku_app/node_modules/pg/lib/pool.js:54:25
12:39:41 web.1  |     at /home/roland/github/heroku_app/node_modules/pg/node_modules/generic-pool/lib/generic-pool.js:271:11
12:39:41 web.1  |     at /home/roland/github/heroku_app/node_modules/pg/lib/pool.js:27:26
12:39:41 web.1  |     at null.<anonymous> (/home/roland/github/heroku_app/node_modules/pg/lib/client.js:169:9)
12:39:41 web.1  |     at EventEmitter.emit (events.js:95:17)
12:39:41 web.1  |     at null.<anonymous> (/home/roland/github/heroku_app/node_modules/pg/lib/connection.js:97:12)
12:39:41 web.1  |     at Socket.EventEmitter.emit (events.js:95:17)
12:39:41 web.1  |     at Socket.<anonymous> (_stream_readable.js:746:14)
12:39:41 web.1  |     at Socket.EventEmitter.emit (events.js:92:17)
12:39:41 web.1  | exited with code 8
12:39:41 system | sending SIGTERM to all processes
SIGTERM received

EDIT my console.logs;

var express = require("express");
var app = express();
app.use(express.logger());

app.get('/', function(request, response) {
  response.send('Hello World!');
  console.log("hello roland");
});

var port = process.env.PORT || 5000;
app.listen(port, function() {
  console.log("Listening on " + port);
});

var pg = require('pg');


pg.connect(process.env.DATABASE_URL, function(err, client, done) {
   console.log(err+"!!!!!!!!!!!!!!!");
  client.query('SELECT * FROM your_table', function(err, result) {
    done();
    if(err) return console.error(err);
    console.log(result.rows);
  });
});

Answer 1

It's Heroku's problem. The "process.env.DATABASE_URL" variable they tell you to use in pg.connect is not functioning.

A simple

console.log(process.env.DATABASE_URL);

Will show that this variable is undefined.

Until Heroku offers a fix, you can hard-code the connection URL as the first argument to pg.connect().

To find your credentials, you can go to your app's PostgreSQL add-on connection settings through http://heroku.com.

The new pg.connect method will look like

var connectionString = "postgres://*USERNAME*:*PASSWORD*@*HOST*:*PORT*/*DATABASE*"

pg.connect(connectionString, function(err, client, done) {
   client.query('SELECT * FROM your_table', function(err, result) {
      done();
      if(err) return console.error(err);
      console.log(result.rows);
   });
});