Updated Dockerfile* and .dockerignore

[mtelvers]

To fix --version parameter

[MisterDA]

I think that dune subst is useless here, we're using dune-build-info to embed the build information, and we're not substituting strings like VERSION in the source.

[mtelvers]

I have tried it without dune subst and it does seem to be necessary:

$ grep subst Dockerfile.worker
RUN opam exec -- dune subst

Then build it and test:

~/ocluster$ docker build -f Dockerfile.worker .
Sending build context to Docker daemon  1.726MB
Step 1/17 : FROM ocaml/opam:debian-11-ocaml-4.13@sha256:fe25836078456e1691b59e28b8fdf1a1feb34f122c9810642282d5d9530fb4ef AS build
...
Successfully built b8852f6f0651
~/ocluster$ docker run b8852f6f0651 --version
v0.1-101-g18e2b79

If I remove the line: sed -i '/dune subst/d' Dockerfile.worker

~/ocluster$ docker build -f Dockerfile.worker .
Sending build context to Docker daemon  1.726MB
Step 1/16 : FROM ocaml/opam:debian-11-ocaml-4.13@sha256:fe25836078456e1691b59e28b8fdf1a1feb34f122c9810642282d5d9530fb4ef AS build
...
Successfully built 54a00130a9d5
~/ocluster$ docker run 54a00130a9d5 --version
n/a

[MisterDA]

I've tested it too and it's correct, but I don't understand why dune subst works in this case. Without it however it's clear what's happening: dune doesn't embed build information unless the executable gets promoted or installed.

I'd be interested in knowing why the build info gets embedded in that case. Otherwise, something that works too and imo isn't so bad:

diff --git a/Dockerfile.worker b/Dockerfile.worker
index 8d52928..f0fc39a 100644
--- a/Dockerfile.worker
+++ b/Dockerfile.worker
@@ -7,12 +7,12 @@ RUN opam pin -yn /src/obuilder/
 WORKDIR /src
 RUN opam install -y --deps-only .
 ADD --chown=opam . .
-RUN opam exec -- dune subst
-RUN opam config exec -- dune build ./_build/install/default/bin/ocluster-worker
+RUN opam config exec -- dune build -p ocluster,ocluster-api @install
+RUN opam config exec -- dune install --prefix=/usr/local --destdir=pkg --section=bin --relocatable ocluster

 FROM debian:11
 RUN apt-get update && apt-get install docker.io libev4 curl gnupg2 git libsqlite3-dev ca-certificates netbase -y --no-install-recommends
 WORKDIR /var/lib/ocluster-worker
 ENTRYPOINT ["/usr/local/bin/ocluster-worker"]
 ENV PROGRESS_NO_TRUNC=1
-COPY --from=build /src/_build/install/default/bin/ocluster-worker /usr/local/bin/
+COPY --from=build /src/pkg/usr/local/bin/ocluster-worker /usr/local/bin/

[MisterDA]

ah, dune subst also creates a (version ...) stanza in the _build directory, that's why it works.