Creating the correct dockerfile for an API REST in Phoenix

Phoenix Forum Questions / Help
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1

I am trying to dockerize a simple phoenix api rest service I have tried with the next two docker files:

FROM elixir:latest

RUN apt-get update && \
apt-get -y install sudo

ADD . /app

RUN mix local.hex --force \
&& mix local.rebar --force
RUN mix archive.install hex phx_new 1.4.0-dev.0

RUN curl -sL https://deb.nodesource.com/setup_12.x | bash -
RUN apt-get install -y nodejs

WORKDIR /app

RUN cd assets && npm install

RUN cd ../

RUN mix deps.get

RUN mix compile

EXPOSE 4000

CMD ["mix", "clean"]
CMD ["mix", "ecto.setup"]
CMD ["mix", "phx.server"]

And a more simple one:

FROM elixir:alpine

RUN apk update

ADD . .

RUN mix local.hex --force && mix local.rebar --force
RUN mix archive.install hex phx_new --force
RUN apk update && apk add inotify-tools
RUN mix deps.get
RUN mix compile

CMD ["mix", "clean"]
CMD ["mix", "ecto.setup"]
CMD ["mix", "phx.server"]

With both I am able to create the docker image and also to run the docker container but when I try to hit any endpoint (from postman) I get the next:

postmanerror1

postmanerror2

Any ideas of why am I getting this?

I have already research about the socket hang up error in postman and may be related to the ports already in use but the problem here is that I am not using any of the ports where I expose or map with my docker container when running docker run -p XXXX:XXXX <image-name>.

Please can you help me with this?

2

did just that some weeks ago

https://github.com/ahsf/ex_api_release_demo

EDIT: repo is now private again. If there is any further need I can fork it to a pubic repo.

2 Likes
3

Hi @Sebb thanks for your reply I have used and example of your Dockerfile but when running the container it prints the next:

[error] `inotify-tools` is needed to run `file_system` for your system, check https://github.com/rvoicilas/inotify-tools/wiki for more information about how to install it. If it's already installed but not be found, appoint executable file with `config.exs` or `FILESYSTEM_FSINOTIFY_EXECUTABLE_FILE` env.
[warning] Could not start Phoenix live-reload because we cannot listen to the file system.
You don't need to worry! This is an optional feature used during development to
refresh your browser when you save files and it does not affect production.
4

the container is meant to run in MIX_ENV=prod which will not use Phoenix.LiveReloader — Phoenix Live-Reload v1.4.0

I will make the repo private again, because we make random changes to this for testing.

1 Like
5

Please is it possible to make it public again?

6

@Sebb thanks for the reply, actually, the container runs but I get the same message from postman: socker hang up. Now that you are here @dbytecoderc do you have a working docker container with a Phoenix/Elixir REST API?

7
1 Like
8

check the config which port is used. See also Container networking | Docker Documentation

Also note, that the readme is wrong. A colleague changed the language from english to french, so you can’t post hello but salut. I’ll fix that for the public repo next week.

1 Like
9

Thank you

10

FIXED: The problem is that Elixir/Phoenix applications configure the connection from other machines inside the dev.exs file, I had to change the line: http: [ip: {127, 0, 0, 1}, port: 4000] to => http: [ip: {0, 0, 0, 0}, port: 4000], actually the comments in the file explicity says that: “Change to ip: {0, 0, 0, 0} to allow access from other machines.”. Though, thanks to @Sebb for the time answering in this topic.

Also, my final simplest (non-production) Dockerfile looks like this:

FROM elixir:alpine
COPY . .
RUN apk update && apk add inotify-tools
RUN mix local.hex --force && \
    mix local.rebar --force
RUN mix do deps.get, deps.compile
EXPOSE 4000
CMD ["mix", "phx.server"]