I’m looking into deploying Bors-NG for use in my company’s private repositories. Since I don’t currently have any Erlang/Elixir deployments, I thought using Docker would be an easier way to get going. The source repository contains a development Dockerfile, so I thought I would start there and adapt it for production settings.
Unfortunately, I ran into an issue when using mix release to build a standalone application, so that I can generate a final image without the Elixir/NodeJS runtimes. The built configuration seems to contain hardcoded values of the environment variables at the time of build, instead of looking them up at runtime as I expected.
Here is the (two-stage) Dockerfile I currently have:
ARG ELIXIR_VERSION=1.4.5
FROM elixir:${ELIXIR_VERSION} as builder
ENV LANG=C.UTF-8 LC_ALL=C.UTF-8
RUN apt-get update -q && apt-get install -y build-essential libtool autoconf curl
RUN DEBIAN_CODENAME=$(sed -n 's/VERSION=.*(\(.*\)).*/\1/p' /etc/os-release) && \
curl -q https://deb.nodesource.com/gpgkey/nodesource.gpg.key | apt-key add - && \
echo "deb http://deb.nodesource.com/node_8.x $DEBIAN_CODENAME main" | tee /etc/apt/sources.list.d/nodesource.list && \
apt-get update -q && \
apt-get install -y nodejs
RUN mix local.hex --force && \
mix local.rebar --force && \
mix hex.info
WORKDIR /app
ADD ./bors-ng/ /app/
# Set default environment for building
ENV MIX_ENV=prod
ENV GITHUB_CLIENT_ID= GITHUB_CLIENT_SECRET= GITHUB_INTEGRATION_ID=0 GITHUB_INTEGRATION_PEM=
ENV DATABASE_URL=
ENV PORT=9999 PUBLIC_HOST=localhost SECRET_KEY_BASE= GITHUB_WEBHOOK_SECRET=
RUN mix deps.get
RUN cd /app/apps/bors_frontend && npm install && npm run deploy
RUN mix release --env=$MIX_ENV
####
FROM debian:jessie-slim
RUN apt-get update -q && apt-get install -y --no-install-recommends git-core libssl1.0.0
ENV LANG=C.UTF-8
WORKDIR /app
COPY --from=builder /app/_build/prod/rel/ /app/
CMD ["./bors_frontend/bin/bors_frontend", "foreground"]
Here is sys.config as generated at first run. Notice how some variables are left to be interpolated at runtime, and others have already been replaced:
%% Generated - edit/create /app/bors_frontend/sys.config instead.
[{sasl,[{errlog_type,error}]},
{bors_database,
[{ecto_repos,['Elixir.BorsNG.Database.Repo']},
{'Elixir.BorsNG.Database.Repo',
[{adapter,'Elixir.Ecto.Adapters.Postgres'},
{url,<<>>},
{pool_size,10},
{ssl,true},
{loggers,[{'Elixir.Ecto.LogEntry',log,[]}]}]}]},
{wobserver,
[{mode,plug},
{security,'Elixir.BorsNG.WobserverSecurity'},
{remote_url_prefix,<<"/wobserver">>},
{security_key,
<<107,174,131,109,206,203,6,74,170,227,134,12,103,79,20,170,8,133,
92,143,161,31,0,9,97,245,65,49,197,208,56,146,135,116,103,245,
55,202,156,161,188,135,203,114,77,40,124,193,62,91,10,21,127,8,
69,164,24,39,157,31,46,205,179,241,253,102,232,32,39,0,195,180,
220,45,28,57,70,172,252,48,140,12,48,134,82,181,100,203,30,55,
147,118,24,127,32,81,185,215,225,140,210,153,68,202,159,155,68,
249,18,130,31,0,82,221,22,228,92,54,227,80,252,207,65,17,33,88,
59,122>>}]},
{bors_frontend,
[{ecto_repos,[]},
{'Elixir.BorsNG',
[{command_trigger,<<"bors">>},
{home_url,<<"https://bors.tech/">>},
{allow_private_repos,false}]},
{'Elixir.BorsNG.Endpoint',
[{render_errors,
[{view,'Elixir.BorsNG.ErrorView'},
{accepts,[<<"html">>,<<"json">>]}]},
{pubsub,
[{name,'Elixir.BorsNG.PubSub'},
{adapter,'Elixir.Phoenix.PubSub.PG2'}]},
{http,[{port,{system,<<"PORT">>}}]},
{url,
[{host,{system,<<"PUBLIC_HOST">>}},
{scheme,<<"https">>},
{port,443}]},
{check_origin,false},
{cache_static_manifest,<<"priv/static/manifest.json">>},
{secret_key_base,<<>>}]},
{'Elixir.BorsNG.WebhookParserPlug',[{webhook_secret,<<>>}]}]},
{bors_github,
[{site,<<"https://api.github.com">>},
{server,'Elixir.BorsNG.GitHub.Server'},
{oauth2,'Elixir.BorsNG.GitHub.OAuth2'},
{'Elixir.BorsNG.GitHub.OAuth2',[{client_id,<<>>},{client_secret,<<>>}]},
{'Elixir.BorsNG.GitHub.Server',[{iss,0},{pem,<<>>}]}]},
{bors_worker,[{ecto_repos,[]}]},
{logger,
[{level,info},
{console,
[{format,<<"$time $metadata[$level] $message\n">>},
{metadata,[request_id]}]}]}].
Apologies if I’m committing any obvious mistakes, as I don’t have any production experience with Elixir apps.
