I'm doing a multi-stage Docker build:
# Dockerfile
########## Build stage ##########
FROM golang:1.10 as build
ENV TEMP /go/src/github.com/my-id/my-go-project
WORKDIR $TEMP
COPY . .
RUN make build
########## Final stage ##########
FROM alpine:3.4
# ...
ENV HOME /home/$USER
ENV TEMP /go/src/github.com/my-id/my-go-project
COPY --from=build $TEMP/bin/my-daemon $HOME/bin/
RUN chown -R $USER:$GROUP $HOME
USER $USER
ENTRYPOINT ["my-daemon"]
and the Makefile
contains in part:
build: bin
go build -v -o bin/my-daemon cmd/my-daemon/main.go
bin:
mkdir $@
This all works just fine with a docker build
.
Now I want to use Codeship, so I have:
# codeship-services.yml
cachemanager:
build:
image: my-daemon
dockerfile: Dockerfile
and:
# codeship-steps.yml
- name: my-daemon build
tag: master
service: my-service
command: true
The issue is if I do jet steps --master
, it builds everything OK, but then runs the container as if I did a docker run
. Why? I don't want it to do that.
It's as if I would have to have two separate Dockerfile
s: one only for the build stage and one only for the run stage and use the former with jet
. But then this defeats the point of Docker multi-stage builds.
I was able to solve this problem using multi-stage builds split into two different files following this guide: https://documentation.codeship.com/pro/common-issues/caching-multi-stage-dockerfile/
Basically, you'll take your existing Dockerfile and split it into two files like so, with the second referencing the first:
# Dockerfile.build-stage
FROM golang:1.10 as build-stage
ENV TEMP /go/src/github.com/my-id/my-go-project
WORKDIR $TEMP
COPY . .
RUN make build
# Dockerfile
FROM build-stage as build-stage
FROM alpine:3.4
# ...
ENV HOME /home/$USER
ENV TEMP /go/src/github.com/my-id/my-go-project
COPY --from=build $TEMP/bin/my-daemon $HOME/bin/
RUN chown -R $USER:$GROUP $HOME
USER $USER
ENTRYPOINT ["my-daemon"]
Then, in your codeship-service.yml file:
# codeship-services.yml
cachemanager-build:
build:
dockerfile: Dockerfile.build-stage
cachemanager-app:
build:
image: my-daemon
dockerfile: Dockerfile
And in your codeship-steps.yml file:
# codeship-steps.yml
- name: cachemanager build
tag: master
service: cachemanager-build
command: <here you can run tests or linting>
- name: publish to registry
tag: master
service: cachemanager-app
...
I don't think you want to actually run the Dockerfile
because it will start your app. We use the second stage to push a smaller build to an image registry.