Do you export from the .env file?

Yeah I exported!

Can you then please tell more about your process?

How does your Dockerfile look like? Your entrypoint script? Your relevant config files?

The problem was that I was using System.fetch_env!/1, so all env vars weren’t loading on compile time… Changing to System.get_env/2 solved the issue!

However I’m getting two new problem now:

1 - When I create a release with MIX_ENV=prod mix release and then run _build/prod/rel/conts/bin/conts eval Conts.Release.migrate I get the following error:

** (RuntimeError) connect raised KeyError exception: key :database not found.

This is my runtime.exs:

import Config

secret_key_base = System.get_env("SECRET_KEY_BASE")
session_cookie_name = System.get_env("SESSION_COOKIE_NAME")
session_cookie_signing_salt = System.get_env("SESSION_COOKIE_SIGNING_SALT")
session_cookie_encryption_salt = System.get_env("SESSION_COOKIE_ENCRYPTION_SALT")

app_port = String.to_integer(System.get_env("PORT", "4000"))
app_hostname = System.get_env("HOST", "localhost")

db_url = System.get_env("DB_URL")
pool_size = String.to_integer(System.get_env("POOL_SIZE", "10"))

config :conts, Conts.Repo,
  adapter: Ecto.Adapters.Postgres,
  url: db_url,
  pool_size: pool_size,
  ssl: false

config :conts, ContsWeb.Endpoint,
  load_from_system_env: true,
  http: [:inet6, port: {:system, "PORT"}],
  secret_key_base: secret_key_base,
  session_cookie_name: session_cookie_name,
  session_cookie_signing_salt: session_cookie_signing_salt,
  session_cookie_encryption_salt: session_cookie_encryption_salt

config :conts,
  app_port: app_port

config :conts,
  app_hostname: app_hostname

The strange part is that if I set :show_sensitive_data_on_connection_error to true, this is the output:

** (KeyError) key :database not found in: [pool_index: 1, types: Postgrex.DefaultTypes, hostname: "localhost", username: "matthew", port: 5432, repo: Conts.Repo, telemetry_prefix: [:conts, :repo], otp_app: :conts, timeout: 15000, adapter: Ecto.Adapters.Postgres, show_sensitive_data_on_connection_error: true, ssl: false, pool_size: 2, pool: DBConnection.ConnectionPool]

Why the :username is getting my system’s username? I don’t even set that anywhere…

2 - When I run mix test, I got this error on controllers: ** (ArgumentError) cookie store expects conn.secret_key_base to be set

However, on test env the secret_key_base wasn’t set by default?

this is my config.exs:

# This file is responsible for configuring your application
# and its dependencies with the aid of the Mix.Config module.
#
# This configuration file is loaded before any dependency and
# is restricted to this project.

# General application configuration
use Mix.Config

config :conts,
  ecto_repos: [Conts.Repo],
  generators: [binary_id: true]

# Configures the endpoint
config :conts, ContsWeb.Endpoint,
  url: [host: "localhost"],
  secret_key_base: "JqlSibgU/Ykrwvzz1ByJn2xayNDJlXkuBzmqHIW2yILDXSI3IHB2VbTqde/sIQw4",
  render_errors: [view: ContsWeb.ErrorView, accepts: ~w(html json), layout: false],
  pubsub_server: Conts.PubSub,
  live_view: [signing_salt: "LvrsHaeP"]

# Configures Elixir's Logger
config :logger, :console,
  format: "$time $metadata[$level] $message\n",
  metadata: [:request_id]

# Use Jason for JSON parsing in Phoenix
config :phoenix, :json_library, Jason

if Mix.env() != :prod do
  config :git_hooks,
    auto_install: true,
    verbose: true,
    hooks: [
      pre_commit: [
        tasks: [
          {:cmd, "mix format"},
          {:cmd, "mix credo --strict"}
        ]
      ],
      pre_push: [
        verbose: false,
        tasks: [
          {:cmd, "mix dialyzer"},
          {:cmd, "mix test"},
          {:cmd, "echo 'success!'"}
        ]
      ]
    ]
end

# Mailing configs
email_domain = "boosting.tech"

config :conts, Conts.Mailing,
  adapter: Bamboo.LocalAdapter,
  open_email_in_browser_url: "http://localhost:4000/sent_emails"

# Pow
config :conts, :pow,
  user: Conts.Accounts.User,
  repo: Conts.Repo,
  extensions: [PowResetPassword, PowEmailConfirmation],
  web_module: ContsWeb,
  controller_callbacks: Pow.Extension.Phoenix.ControllerCallbacks,
  mailer_backend: Conts.Mailing,
  web_module_mailer: Conts

# Conts custom configs

config :conts, mailing_default_from_name: "Sistema Conts"
config :conts, mailing_default_from_email: "noreplyconts@boosting.tech"

# Import environment specific config. This must remain at the bottom
# of this file so it overrides the configuration defined above.
import_config "#{Mix.env()}.exs"

Other files:

Dockerfile:

# Set global arg for multistage
ARG DB_URL

FROM elixir:1.11.2-alpine AS builder

RUN apk add --no-cache yarn build-base

RUN mkdir /app
WORKDIR /app

ARG DB_URL
ARG SECRET_KEY_BASE
ARG SESSION_COOKIE_NAME
ARG SESSION_COOKIE_SIGNING_SALT
ARG SESSION_COOKIE_ENCRYPTION_SALT

# Mix env
ENV MIX_ENV=prod \
    DB_URL=$DB_URL \
    SECRET_KEY_BASE=$SECRET_KEY_BASE \
    SESSION_COOKIE_NAME=$SESSION_COOKIE_NAME \
    SESSION_COOKIE_SIGNING_SALT=$SESSION_COOKIE_SIGNING_SALT \
    SESSION_COOKIE_ENCRYPTION_SALT=$SESSION_COOKIE_ENCRYPTION_SALT 

# Cache elixir deps
ADD mix.exs mix.lock ./
RUN mix local.rebar
RUN mix local.hex --force
RUN mix do deps.get, deps.compile

# Same with node deps
COPY assets assets
RUN yarn --cwd assets

COPY lib lib
COPY config config
COPY priv priv

# Run frontend build, compile, and digest assets
RUN yarn --cwd assets deploy && \
    cd - && \
    mix do compile, phx.digest

RUN mix release

# ---- Application Stage ----
FROM alpine AS app

ARG DB_URL

ENV MIX_ENV=prod \
    DB_URL=$DB_URL \
    SHELL=/bin/fish

# Intall needed packages
RUN apk --no-cache upgrade && \
    apk add --no-cache openssl \
      ncurses-libs postgresql-client fish

# Copy over the build artifact from the previous step and create a non root user
RUN adduser -D -h /home/app app
WORKDIR /home/app
COPY --from=builder /app/_build .
RUN chown -R app: ./prod
USER app

COPY entrypoint.sh .

# Run the Phoenix app
CMD ["./entrypoint.sh"]

entrypoint.sh:

#!/bin/sh
# Docker entrypoint script.

# Wait until Postgres is ready
while ! pg_isready -q -d $DB_URL 
do
  echo "$(date) - waiting for database to start"
  sleep 2
done

echo "Connected to the database"

./prod/rel/conts/bin/conts eval Conts.Release.migrate

./prod/rel/conts/bin/conts start

What is DB_URL in the system environment?

Do you perhaps have no dockerignore file which contains _build and deps and therefore partial builds slip into your container, which again might cause config values to exist that you do not want to exist?

Well, I’m trying to generate the release on my local machine to test, and DB_URL is being set to postgresql://postgres:postgres@localhost/conts_dev

I’m creating the release as:

MIX_ENV=prod DB_URL=postgresql://postgres:postgres@localhost/conts_dev mix release

And how do you run it?

runned as: _build/prod/rel/conts/bin/conts eval Conts.Release.migrate

Before that have you explicitely set and exported the DB_URL?

runtime.exs is re read on each start, but not on build at all, so you have to have the environment set on start, not on build.

Ok, locally I dind’t export the DB_URL, executing in fish shel: setenv DB_URL postgresql://postgres:postgres@localhost:5432/conts_dev, solves the first problem…

In production (Dockerfile) the DB_URL will be set “globally”, so I won’t get this error!

Than you so much! You accompanying me helps so much (:

But the test problem persists…