Cloudfoundry Phoenix

This is a placeholder for now with some problems I've run into deploying phoenix to cloud foundry. I intend to work on these problems and make deployment easier. Also I intend to write up a blog post to help others with common problems.

Be sure to always keep cf logs <app-name> running when deploying your new app.

Known issues

Too Many Database Connections

You will probably need to configure a lower database connection count for CF. This is currently configured in the prod.secret.exs file to be 20. You should just delete prod.secret.exs since it will cause you other problems (see below). Then configure the pool size in prod.exs like so:

config :racing_sites, RacingSites.Repo,
  pool_size: String.to_integer(System.get_env("POOL_SIZE") || "1")

prod.secret.exs is not available

You may notice:

 ERR     ** (Code.LoadError) could not load /tmp/app/config/prod.secret.exs

We don't need to use the secrets file on CF. Instead you can use an env var.

Firstly setup a secure secret key in an env var:

cf set-env SECRET_KEY_BASE <something-secure>

Then edit the prod config like so:

--- a/config/prod.exs
+++ b/config/prod.exs
@@ -63,4 +63,6 @@ config :logger, level: :info

 # Finally import the config/prod.secret.exs
 # which should be versioned separately.
-import_config "prod.secret.exs"
+
+config :my_app, MyApp.Endpoint,
+  secret_key_base: System.get_env("SECRET_KEY_BASE") || "abc123"

Database URL cannot be accessed in VCAP_SERVICES

You will need to manually set some env var for this:

In order to find what it should be take a look at the VCAP_SERVICES:

cf env <app-name>

Then find the credentials in the output and update the env vars you need.

cf set-env DATABASE_URL <database-url>

and reference it in the config using like so:

config :my_app, MyApp.Repo,
  adapter: Ecto.Adapters.Postgres,
  url: System.get_env("DATABASE_URL"),
  pool_size: String.to_integer(System.get_env("POOL_SIZE") || "1")

App URL cannot be accessed in VCAP_APPLICATION

You will need to manually set some env var for this:

cf set-env APP_URL myapp.cfapps.io

and reference it in the config using System.get_env("APP_URL") like so:

--- a/config/prod.exs
+++ b/config/prod.exs
@@ -13,7 +13,7 @@ use Mix.Config
 # which you typically run after static files are built.
 config :my_app, MyApp.Endpoint,
   http: [port: {:system, "PORT"}],
-  url: [host: "example.com", port: 80],
+  url: [host: System.get_env("APP_URL"), port: 80],
   cache_static_manifest: "priv/static/manifest.json",
   server: true

Uploading tonnes of files

Add the following to a .cfignore file.

/_build
/db
/deps
/*.ez
erl_crash.dump
/node_modules
/rel

Static assets are not available

You may notice:

[error] Could not find static manifest at "/home/vcap/app/_build/prod/lib/drivethrough/priv/static/manifest.json". Run "mix phoenix.digest" after building your static files or remove the configuration from "config/prod.exs."

Assuming you are using the .cfignore I referred to above you can build your assets locally before pushing to cloud foundry. Try the following to deploy:

brunch build --production
MIX_ENV=prod mix phoenix.digest && cf push

If this doesn't fix the problem make sure that you don't have /priv/static in your .cfignore file.