How to configure different dockerfile for development and production - docker

Question

I use docker for development and in production for laravel project. I have slightly different dockerfile for development and production. For example I am mounting local directory to docker container in development environment so that I don't need to do docker build for every change in code.
As mounted directory will only be available when running the docker container I can't put commands like "composer install" or "npm install" in dockerfile for development.
Currently I am managing two docker files, is there any way that I can do this with single docker file and decide which commands to run when doing docker build by sending parameters.
What I am trying to achieve is
In docker file
...
IF PROD THEN RUN composer install
...
During docker build
docker build [PROD] -t mytag .

Answer 1

As a best practice you should try to aim to use one Dockerfile to avoid unexpected errors between different environments. However, you may have a usecase where you cannot do that.
The Dockerfile syntax is not rich enough to support such a scenario, however you can use shell scripts to achieve that.
Create a shell script, called install.sh that does something like:
if [ ${ENV} = "DEV" ]; then
composer install
else
npm install
fi
In your Dockerfile add this script and then execute it when building
...
COPY install.sh install.sh
RUN chmod u+x install.sh && ./install.sh
...
When building pass a build arg to specify the environment, example:
docker build --build-arg "ENV=PROD" ...

Answer 2

UPDATE (2020):
Since this was written 3 years ago, many things have changed (including my opinion about this topic). My suggested way of doing this, is using one dockerfile and using scripts. Please see #yamenk's answer.
ORIGINAL:
You can use two different Dockerfiles.
# ./Dockerfile (non production)
FROM foo/bar
MAINTAINER ...
# ....
And a second one:
# ./Dockerfile.production
FROM foo/bar
MAINTAINER ...
RUN composer install
While calling the build command, you can tell which file it should use:
$> docker build -t mytag .
$> docker build -t mytag-production -f Dockerfile.production .

Answer 3

You can use build args directly without providing additional sh script. Might look a little messy, though. But it works.
Dockerfile must be like this:
FROM alpine
ARG mode
RUN if [ "x$mode" = "xdev" ] ; then echo "Development" ; else echo "Production" ; fi
And commands to check are:
docker build -t app --build-arg mode=dev .
docker build -t app --build-arg mode=prod .

Answer 4

I have tried several approaches to this, including using docker-compose, a multi-stage build, passing an argument through a file and the approaches used in other answers. My company needed a good way to do this and after trying these, here is my opinion.
The best method is to pass the arg through the cmd. You can pass it through vscode while right clicking and choosing build image
Image of visual studio code while clicking image build
using this code:
ARG BuildMode
RUN echo $BuildMode
RUN if [ "$BuildMode" = "debug" ] ; then apt-get update \
&& apt-get install -y --no-install-recommends \
unzip \
&& rm -rf /var/lib/apt/lists/* \
&& curl -sSL https://aka.ms/getvsdbgsh | bash /dev/stdin -v latest -l /vsdbg ; fi
and in the build section of dockerfile:
ARG BuildMode
ENV Environment=${BuildMode:-debug}
RUN dotnet build "debugging.csproj" -c $Environment -o /app
FROM build AS publish
RUN dotnet publish "debugging.csproj" -c $Environment -o /app

Answer 5

The best way to do it is with .env file in your project.
You can define two variables CONTEXTDIRECTORY and DOCKERFILENAME
And create Dockerfile-dev and Dockerfile-prod
This is example of using it:
docker compose file:
services:
serviceA:
build:
context: ${CONTEXTDIRECTORY:-./prod_context}
dockerfile: ${DOCKERFILENAME:-./nginx/Dockerfile-prod}
.env file in the root of project:
CONTEXTDIRECTORY=./
DOCKERFILENAME=Dockerfile-dev
Be careful with the context. Its path starts from the directory with the dockerfile that you specified, not from docker-compose directory.
In default values i using prod, because if you forget to specify env variables, you won't be able to accidentally build a dev version in production
Solution with diffrent dockerfiles is more convinient, then scripts. It's easier to change and maintain