I've deployed a few different Elixir services to the hosting platform https://render.com and found their provided documentation to be lacking for real-world Phoenix apps. Especially if you're using Live View. Here's an augmentation to their guide with the extra steps you might be missing.

Initial Setup

Follow the official guide: https://render.com/docs/deploy-phoenix but don't deploy your service yet. You'll need to make some changes:

Add Evars

Add some new evars:

• ELIXIR_VERSION = 1.10.3 or whatever version you like. But the default version is older and breaks the build for new Elixir apps
• DATABASE_URL = The connection string for the database you'll be using

Migrations

After, do these things. MAKE SURE YOU REPLACE WITH YOUR APP NAME :

• Add a new script for running migrations (./build_and_migrate.sh):

#!/usr/bin/env bash # exit on error set -o errexit ./build.sh # Run migrations _build/prod/rel/<app_name>/bin/<app_name> eval "Render.Release.migrate" 

• Make that new script executable.
• Make a module in your application for running migrations (lib/<app_name>_web/render_release.ex):

defmodule Render.Release do @moduledoc """ Responsible for custom release commands """ @app :<app_name> def migrate do # Allows the migration script to connect to a database using SSL. Application.ensure_all_started(:ssl) for repo <- repos() do {:ok, _, _} = Ecto.Migrator.with_repo(repo, &Ecto.Migrator.run(&1, :up, all: true)) end end def rollback(repo, version) do # Allows the migration script to connect to a database using SSL. Application.ensure_all_started(:ssl) {:ok, _, _} = Ecto.Migrator.with_repo(repo, &Ecto.Migrator.run(&1, :down, to: version)) end defp repos do Application.load(@app) Application.fetch_env!(@app, :ecto_repos) end end 

• Change the deploy command for your render app to be ./build_and_migrate.sh instead of ./build.sh

Using a Database that Requires SSL

Unless you're using a private database on Render, you'll want to connect to your PG instance using SSL. To do that, you've got to

• Uncomment the line in releases.exs that says ssl: true for your app's repo:

... config :<app_name>, <AppName>.Repo, ssl: true, <-- this line, it's commented by default. url: database_url, 

And then

• Add the :ssl application to extra_applications in mix.exs:

def application do [ mod: {<AppName>.Application, []}, extra_applications: [:logger, :runtime_tools, :ssl] <-- added :ssl to the end of this list. ] end 

Troubleshooting

If you run into an issue with Phoenix Live View breaking and reloading the page every few seconds, you might have enabled force_ssl in your endpoint, and it could be trying to redirect your web socket traffic to an https scheme. Which is strange. I ran into this once, and haven't found a great workaround for it.

PgBouncer

If your database does pooling using pg_bouncer then open up releases.exs and add prepare: :unnamed to your repo config.

config :<app_name>, <AppName>.Repo, ssl: true, url: database_url, pool_size: String.to_integer(System.get_env("POOL_SIZE") || "10"), prepare: :unnamed <-- this line!