I have 2 Dockerfile, 1 for dev, and 1 for prod:
PROD:
FROM golang AS builder
WORKDIR /go/src/gitlab.com/company/project
COPY . .
RUN go build -o ./release/api .
FROM scratch
EXPOSE 9999
COPY --from=builder /go/src/gitlab.com/company/project/release/api .
CMD ["./api"]
and DEV:
FROM golang
WORKDIR /go/src/gitlab.com/company/PROJECT
COPY . .
RUN go build -o ./release/api .
CMD ["./release/api"]
I would like to merge those two into a single one, as maintaining 2 Dockerfile is a bad practice
The main difference is that in dev, I work on golang image, which is practical, and in prod, I work with scratch image, which reduce a lot the size of my binary.
It seems that I can use multiple stages in a Dockerfile, and specify stage name at build time:
docker build . --target=builder
But If I do this, I don't know how to conditionally run my app in the first stage = [ If I am in dev, run the app in the first stage, otherwise, run the app in the second stage]
How should I do it ?
What about something like this? I didn't test it and didn't think through your example deeply, but maybe is somewhere close to what you need/helps you finding out the final solution?
FROM golang:alpine AS base
WORKDIR /go/src/gitlab.com/company/project
COPY . .
RUN go build -o ./release/api .
FROM base AS dev
CMD ["./release/api"]
FROM scratch AS prod
EXPOSE 9999
COPY --from=base /go/src/gitlab.com/company/project/release/api .
CMD ["./api"]
Depending on the value specified in target docker build --target=prod or docker build --target=dev, a different image will get built.