Phoenix deployment on fly.io

fly.toml

app = "sample-ephoenix"
kill_signal = "SIGINT"
kill_timeout = 5
processes = []

[build]
  dockerfile = "prod.Dockerfile"

[env]
  PORT = "8081"

[experimental]
  allowed_public_ports = []
  auto_rollback = true

[[services]]
  internal_port = 8081
  protocol = "tcp"
  script_checks = []
  [services.concurrency]
    hard_limit = 50
    soft_limit = 40

  [[services.ports]]
    handlers = ["tls", "http"]
    port = 443

  [[services.tcp_checks]]
    grace_period = "10s"
    interval = "15s"
    restart_timeout = 0
    timeout = "2s"

prod.Dockerfile

# syntax=docker/dockerfile:1.3-labs

FROM elixir:latest

COPY . /app
WORKDIR /app

# Env for prod, port control
ENV MIX_ENV=prod PORT=8081

# Install tools
RUN <<EOF
echo "installing rebar..."
mix local.rebar --force
echo "installing hex..."
mix local.hex --force --yes
EOF

# Get dependencies
RUN mix deps.get --only prod

# Compile application and assets
RUN <<EOF
mix do compile
mix assets.deploy
EOF

# Expose directive
EXPOSE 4000

# Needs SECRET_KEY_BASE in env

CMD ["mix", "phx.server"]