Error with DATABASE_URL when deploying Phoenix application to Heroku

biske · November 28, 2019, 10:02pm

Hi, I’m following https://github.com/phoenixframework/phoenix/blob/master/guides/deployment/heroku.md to deploy using Heroku containers.

Here’s the example repo: https://github.com/biske/hello

When I push to heroku I get following error:

Apples-MacBook-Pro:hello ivanbisevac$ git push heroku master
Enumerating objects: 83, done.
Counting objects: 100% (83/83), done.
Delta compression using up to 8 threads
Compressing objects: 100% (75/75), done.
Writing objects: 100% (83/83), 97.06 KiB | 6.93 MiB/s, done.
Total 83 (delta 4), reused 0 (delta 0)
remote: Compressing source files... done.
remote: Building source:
remote: === Fetching app code
remote: 
remote: === Building web (Dockerfile)
remote: Sending build context to Docker daemon  368.6kB
remote: Step 1/25 : FROM elixir:1.9.0-alpine AS build
remote: 1.9.0-alpine: Pulling from library/elixir
remote: e7c96db7181b: Pulling fs layer
remote: c306444e2774: Pulling fs layer
remote: 4b80324f258b: Pulling fs layer
remote: e7c96db7181b: Verifying Checksum
remote: e7c96db7181b: Download complete
remote: 4b80324f258b: Verifying Checksum
remote: 4b80324f258b: Download complete
remote: e7c96db7181b: Pull complete
remote: c306444e2774: Verifying Checksum
remote: c306444e2774: Download complete
remote: c306444e2774: Pull complete
remote: 4b80324f258b: Pull complete
remote: Digest: sha256:bd6e03f00f57a121f6f31374d693e9027ce6053e25700be4d7c64f83dd249a56
remote: Status: Downloaded newer image for elixir:1.9.0-alpine
remote:  ---> 7a6d28e4b511
remote: Step 2/25 : RUN apk add --update build-base npm git
remote:  ---> Running in 244929b60841
remote: fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/main/x86_64/APKINDEX.tar.gz
remote: fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/community/x86_64/APKINDEX.tar.gz
remote: (1/31) Upgrading musl (1.1.20-r4 -> 1.1.20-r5)
remote: (2/31) Installing binutils (2.31.1-r2)
remote: (3/31) Installing libmagic (5.36-r1)
remote: (4/31) Installing file (5.36-r1)
remote: (5/31) Installing gmp (6.1.2-r1)
remote: (6/31) Installing isl (0.18-r0)
remote: (7/31) Installing libgomp (8.3.0-r0)
remote: (8/31) Installing libatomic (8.3.0-r0)
remote: (9/31) Installing libgcc (8.3.0-r0)
remote: (10/31) Installing mpfr3 (3.1.5-r1)
remote: (11/31) Installing mpc1 (1.0.3-r1)
remote: (12/31) Installing libstdc++ (8.3.0-r0)
remote: (13/31) Installing gcc (8.3.0-r0)
remote: (14/31) Installing musl-dev (1.1.20-r5)
remote: (15/31) Installing libc-dev (0.7.1-r0)
remote: (16/31) Installing g++ (8.3.0-r0)
remote: (17/31) Installing make (4.2.1-r2)
remote: (18/31) Installing fortify-headers (1.0-r0)
remote: (19/31) Installing build-base (0.5-r1)
remote: (20/31) Installing nghttp2-libs (1.35.1-r1)
remote: (21/31) Installing libssh2 (1.9.0-r1)
remote: (22/31) Installing libcurl (7.64.0-r3)
remote: (23/31) Installing expat (2.2.8-r0)
remote: (24/31) Installing pcre2 (10.32-r1)
remote: (25/31) Installing git (2.20.1-r0)
remote: (26/31) Upgrading musl-utils (1.1.20-r4 -> 1.1.20-r5)
remote: (27/31) Installing c-ares (1.15.0-r0)
remote: (28/31) Installing http-parser (2.8.1-r0)
remote: (29/31) Installing libuv (1.23.2-r0)
remote: (30/31) Installing nodejs (10.14.2-r0)
remote: (31/31) Installing npm (10.14.2-r0)
remote: Executing busybox-1.29.3-r10.trigger
remote: OK: 235 MiB in 51 packages
remote: Removing intermediate container 244929b60841
remote:  ---> c32d9dd1e1ab
remote: Step 3/25 : RUN mkdir /app
remote:  ---> Running in 1421ee00b856
remote: Removing intermediate container 1421ee00b856
remote:  ---> 99aace19d0bf
remote: Step 4/25 : WORKDIR /app
remote:  ---> Running in e1cb3f87b4d0
remote: Removing intermediate container e1cb3f87b4d0
remote:  ---> c37e5c3877f2
remote: Step 5/25 : RUN mix local.hex --force &&     mix local.rebar --force
remote:  ---> Running in 35ced8130ede
remote: * creating /root/.mix/archives/hex-0.20.1
remote: * creating /root/.mix/rebar
remote: * creating /root/.mix/rebar3
remote: Removing intermediate container 35ced8130ede
remote:  ---> afa2e665d580
remote: Step 6/25 : ENV MIX_ENV=prod
remote:  ---> Running in f5b1950ab144
remote: Removing intermediate container f5b1950ab144
remote:  ---> 8e416fc55c15
remote: Step 7/25 : COPY mix.exs mix.lock ./
remote:  ---> 2c89dc19046c
remote: Step 8/25 : COPY config config
remote:  ---> 5ac08e894b10
remote: Step 9/25 : RUN mix deps.get
remote:  ---> Running in 161800382fd6
remote: ** (RuntimeError) environment variable DATABASE_URL is missing.
remote: For example: ecto://USER:PASS@HOST/DATABASE
remote: 
remote:     (stdlib) erl_eval.erl:680: :erl_eval.do_apply/6
remote:     (stdlib) erl_eval.erl:449: :erl_eval.expr/5
remote:     (stdlib) erl_eval.erl:126: :erl_eval.exprs/5
remote:     (elixir) lib/code.ex:240: Code.eval_string/3
remote:     (mix) lib/mix/config.ex:158: anonymous fn/2 in Mix.Config.__import__!/2
remote:     (elixir) lib/enum.ex:1948: Enum."-reduce/3-lists^foldl/2-0-"/3
remote:     (mix) lib/mix/config.ex:157: Mix.Config.__import__!/2
remote: The command '/bin/sh -c mix deps.get' returned a non-zero code: 1
remote: 
remote: Verifying deploy...
remote: 
remote: !	Push rejected to serene-tor-13468.
remote: 
To https://git.heroku.com/serene-tor-13468.git
 ! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'https://git.heroku.com/serene-tor-13468.git'

perzanko · November 28, 2019, 10:08pm

Have you set up database on your Heroku app? ‘DATABASE_URL is missing’ means that you haven’t exported the environment variable. You probably didn’t add a database as addon on Heroku.

If you use postgres, here is the tutorial how to do it: https://devcenter.heroku.com/articles/heroku-postgresql

biske · November 28, 2019, 11:04pm

Yes, that is covered in this part:

github.com

phoenixframework/phoenix/blob/master/guides/deployment/heroku.md#creating-environment-variables-in-heroku

# Deploying on Heroku

## What we'll need

The only thing we'll need for this guide is a working Phoenix application. For those of us who need a simple application to deploy, please follow the [Up and Running guide](https://hexdocs.pm/phoenix/up_and_running.html).

## Goals

Our main goal for this guide is to get a Phoenix application running on Heroku.

## Limitations

Heroku is a great platform and Elixir performs well on it. However, you may run into limitations if you plan to leverage advanced features provided by Elixir and Phoenix, such as:

- Connections are limited.
  - Heroku [limits the number of simultaneous connections](https://devcenter.heroku.com/articles/http-routing#request-concurrency) as well as the [duration of each connection](https://devcenter.heroku.com/articles/limits#http-timeouts). It is common to use Elixir for real-time apps which need lots of concurrent, persistent connections, and Phoenix is capable of [handling over 2 million connections on a single server](https://www.phoenixframework.org/blog/the-road-to-2-million-websocket-connections).

- Distributed clustering is not possible.
  - Heroku [firewalls dynos off from one another](https://devcenter.heroku.com/articles/dynos#networking). This means things like [distributed Phoenix channels](https://dockyard.com/blog/2016/01/28/running-elixir-and-phoenix-projects-on-a-cluster-of-nodes) and [distributed tasks](https://elixir-lang.org/getting-started/mix-otp/distributed-tasks.html) will need to rely on something like Redis instead of Elixir's built-in distribution.

This file has been truncated. show original

To prove that database url is set I tried (I changed the values of course):

Apples-MacBook-Pro:hello ivanbisevac$ heroku config
=== serene-tor-13468 Config Vars
DATABASE_URL:    postgres://jbkhmewallortj:b44a50b8b938221a9caccbae04622bbf58bbcd60e894d2a309ece17259f2db1a@ec2-174-129-227-80.compute-1.amazonaws.com:5432/de34tt303335l8
POOL_SIZE:       18
SECRET_KEY_BASE: cWV2XTCuO0S4p7+jKdXXLYX9XQn8CzI1vVAW0g34smrV3lkAONjOQRmzv9QIarB

Seems like heroku is not exposing those variables in the build time. Probably heroku.yml from the tutorial is wrong.

perzanko · November 29, 2019, 8:16am

Hmm. The issue could be related to docker. Try use this buildpack instead: https://github.com/HashNuke/heroku-buildpack-elixir.git

biske · November 29, 2019, 9:29am

That’s ok, but my question is not about buildpack deploy, but container one. Whole point is that there is Phoenix documentation how to deploy which doesn’t work.

outlog · November 29, 2019, 10:17pm

think the issue will be solved if you complete these steps: https://github.com/phoenixframework/phoenix/blob/master/guides/deployment/releases.md#runtime-configuration

caike · July 26, 2021, 2:34pm

Make sure the environment variables are created in Heroku, then add the following two lines to the top of the Dockerfile:

ARG DATABASE_URL
ARG SECRET_KEY_BASE