Docker container with build output and no source - docker

Question

I have a build process that converts typescript into javascript, minifies and concatenates css files, etc.
I would like to put those files into an nginx docker container, but I don't want the original javascript / css source to be included, nor the tools that I use to build them. Is there a good way to do this, or do I have to run the build outside docker (or in a separately defined container), then COPY the relevant files in?
This page talks about doing something similar in a manual way, but doesn't explain how to automate the process e.g. with docker-compose or something.

Answer 1

Create a docker images with all required tools to build your code also that can clone code and build it. After build it have to copy
into docker volume for example volume name is /opt/webapp.
Launch build docker container using build image in step 1
docker run -d -P --name BuildContainer -v /opt/webapp:/opt/webapp build_image_name
Launch nginx docker container that will use shared volume of build docker in which your build code resides.
docker run -d -P --name Appserver -v /opt/webapp:/usr/local/nginx/html nginx_image_name
After building and shipping your build code to Appserver . you can delete BuildContainer because that is no more required.
Advantage of above steps:
your build code will in host machine so if one Appserver docker fail or stop then your build code will be safe in host machine and you can launch new docker using that build code.
if you create docker image for building code then every time no need to install required tool while launching docker.
you can build your code in host machine also but if you want your code should be build in fresh environment every time then this will be good. or if you use same host machine to build/compile code every time then some older source code may create problem or git clone error etc.
EDIT:
you can append :ro (Read only) to volume by which one container will not affect another. you can Read more about docker volume Here . Thanks #BMitch for suggestion.

Answer 2

The latest version of docker supports multi-stage builds where build products can be copied from on container to another.
https://docs.docker.com/engine/userguide/eng-image/multistage-build/

Answer 3

This is an ideal scenario for a multi-stage build. You perform the compiling in the first stage, copy the output of that compile to the second stage, and only ship that second stage. Each stage is an independent image that begins with a FROM line. And to transfer files between stages, there's now a COPY --from syntax. The result looks roughly like:
# first stage with your full compile environment, e.g. maven/jdk
FROM maven as build
WORKDIR /src
COPY src /src
RUN mvn install
# second stage starts below with just a jre base image
FROM openjdk:jre
# copy the jar from the first stage here
COPY --from=build /src/result.jar /app
CMD java -jar /app/result.jar
Original answer:
Two common options:
As mentioned, you can build outside and copy the compiled result into the container.
You merge your download, build, and cleanup step into a single RUN command. This is a common best practice to minimize the size of each layer.
An example Dockerfile for the second option would look like:
FROM mybase:latest
RUN apt-get update && apt-get install tools \
&& git clone https://github.com/myproj \
&& cd myproj \
&& make \
&& make install
&& cd .. \
&& apt-get rm tools && apt-get clean \
&& rm -rf myproj
The lines would be a little more complicated than that, but that's the gist.

Answer 4

As #dnephin suggested in his comments on the question and on #pl_rock's answer, the standard docker tools are not designed to do this, but you can use a third party tool like one of the following:
dobi (48 GitHub stars)
packer (6210 GitHub stars)
rocker (759 GitHub stars)
conveyor (152 GitHub stars)
(GitHub stars correct when I wrote the answer)
We went with dobi as it was the first one we heard of (because of this question), but it looks like packer is the most popular.

Answer 5

Create a docker file to run your build process, then run cleanup code
Example:
FROM node:latest
# Provides cached layer for node_modules
ADD package.json /tmp/package.json
RUN cd /tmp && npm install
RUN mkdir -p /dist && cp -a /tmp/node_modules /dist/
RUN cp /tmp/package.json /dist
ADD . /tmp
RUN cd /tmp && npm run build
RUN mkdir -p /dist && cp -a /tmp/. /dist
#run some clean up code here
RUN npm run cleanup
# Define working directory
WORKDIR /dist
# Expose port
EXPOSE 4000
# Run app
CMD ["npm", "run", "start"]
In your docker compose file
web:
build: ../project_path
environment:
- NODE_ENV=production
restart: always
ports:
- "4000"