(DockerBuild) Add hint about how to build for debian plus some cleanup

2 files changed, 44 insertions, 12 deletions

diff --git a/contrib/build-using-docker/Dockerfile b/contrib/build-using-docker/Dockerfile
index 78f1a85..9a6df6b 100644
--- a/contrib/build-using-docker/Dockerfile
+++ b/contrib/build-using-docker/Dockerfile
@@ -4,25 +4,26 @@ FROM $PARENT_IMAGE
 
 ARG GIT_TAG=
 ARG CONFIGURE_OPTS=
-ARG PKGS_TO_INSTALL="curl gcc git make musl-dev tar"
 ARG PKGINIT=true
 ARG PKGADD="apk add"
 ARG PKGDEL="apk del"
 ARG PKGCLEAN=true
+ARG PKGS_TO_ADD="curl gcc git make musl-dev tar"
+ARG PKGS_TO_DEL="curl gcc git make musl-dev tar"
 
 WORKDIR /work
 
 RUN true \
     && $PKGINIT \
-    && $PKGADD $PKGS_TO_INSTALL \
-    && git clone https://git.hiddenalpha.ch/bulk-ln.git . \
+    && $PKGADD $PKGS_TO_ADD \
+    && git clone --depth 1 https://github.com/hiddenalpha/bulk-ln.git . \
     && git config advice.detachedHead false \
     && if test -n "$GIT_TAG"; then git checkout "$GIT_TAG"; fi \
     && ./configure $CONFIGURE_OPTS \
     && make clean && make && make install \
     && find . -not -wholename './dist*' -delete \
     && find /work -exec chown 1000:1000 {} + \
-    && $PKGDEL $PKGS_TO_INSTALL \
+    && $PKGDEL $PKGS_TO_DEL \
     && $PKGCLEAN \
     && true
 
diff --git a/contrib/build-using-docker/README.md b/contrib/build-using-docker/README.md
index 503136e..35f7429 100644
--- a/contrib/build-using-docker/README.md
+++ b/contrib/build-using-docker/README.md
@@ -2,28 +2,59 @@
 Showcase how to build and install
 =================================
 
-Make and install inside a dockerimage.
+Sometimes happy developers (like me) have no choice but using horribly
+restricted systems where setting up tools to run even something as simple as
+configure/make/install becomes a nightmare. I found it to be easier to have a
+Dockerfile to build on a totally unrelated machine (but where I have the needed
+privileges) and then just copy-paste the built result over to where I need it.
+
+
+## Setup variable to reduce annoying repetitions
 
 ```sh
-    curl -sSL http://git.hiddenalpha.ch/bulk-ln.git/plain/contrib/build-using-docker/Dockerfile | sudo docker build . -f -
+IMG=bulk-ln-showcase:latest
 ```
 
-Afer that we can use the image hash printed in last line to refer to our built
-image (replace IMG_REF in commands below by that hash). Alternatively we could
-add [`--tag`](https://docs.docker.com/engine/reference/commandline/build/)
-option to our build command to give the resulting image a name.
+## Make and install dockerimage
+
+```sh
+curl -sSL http://git.hiddenalpha.ch/bulk-ln.git/plain/contrib/build-using-docker/Dockerfile | sudo docker build . -f - -t "${IMG:?}"
+```
+
+## Grab distribution archive
 
 Most probably we wanna get the distribution archive. We can copy it out the
 dockerimage to our host using:
 
 ```sh
-    sudo docker run --rm -i  IMG_REF  sh -c 'true && cd dist && tar c *' | tar x
+sudo docker run --rm -i "${IMG:?}" sh -c 'true && cd dist && tar c *' | tar x
 ```
 
+
+## Play around
+
 Or if we wanna browse the image or play around with the built utility we could
 launch a shell. Once in the shell, try `bulk-ln --help`.
 
 ```sh
-    sudo docker run --rm -ti  IMG_REF  sh
+sudo docker run --rm -ti "${IMG:?}" sh
+```
+
+
+## Other targets
+
+The dockerfile is parameterized and should work for other systems too. For
+example to compile for debian we could use command like below. May set *IMG*
+differently if you need to keep multiple images.
+
+```sh
+curl -sSL http://git.hiddenalpha.ch/bulk-ln.git/plain/contrib/build-using-docker/Dockerfile | sudo docker build . -f - -t "${IMG:?}" \
+    --build-arg PARENT_IMAGE=debian:buster-20220622-slim \
+    --build-arg PKGS_TO_ADD="curl gcc git make libc-dev ca-certificates tar" \
+    --build-arg PKGS_TO_DEL="curl gcc git make libc-dev ca-certificates" \
+    --build-arg PKGINIT="apt update" \
+    --build-arg PKGADD="apt install -y --no-install-recommends" \
+    --build-arg PKGDEL=true \
+    --build-arg PKGCLEAN="apt clean"
 ```