2 files changed, 66 insertions, 6 deletions
diff --git a/contrib/build-using-docker/Dockerfile b/contrib/build-using-docker/Dockerfile
index aaca6ad..c226a8a 100644
--- a/contrib/build-using-docker/Dockerfile
+++ b/contrib/build-using-docker/Dockerfile
@@ -4,7 +4,8 @@ FROM $PARENT_IMAGE
 
 ARG GIT_TAG=
 ARG CONFIGURE_OPTS=
-ARG PKGS_TO_INSTALL="curl gcc git make musl-dev tar zlib-dev"
+ARG PKGS_TO_ADD="curl gcc git make musl-dev tar zlib-dev"
+ARG PKGS_TO_DEL="curl gcc git make musl-dev tar zlib-dev"
 ARG PKGINIT=true
 ARG PKGADD="apk add"
 ARG PKGDEL="apk del"
@@ -14,15 +15,14 @@ WORKDIR /work
 
 RUN true \
     && $PKGINIT \
-    && $PKGADD $PKGS_TO_INSTALL \
-    && git clone http://git.hiddenalpha.ch/DeflateAndInflate.git . \
-    && git config advice.detachedHead false \
-    && if test -n "$GIT_TAG"; then git checkout "$GIT_TAG"; fi \
+    && $PKGADD $PKGS_TO_ADD \
+    && BR=$(if test -n "$GIT_TAG"; then echo " --branch $GIT_TAG"; else echo ""; fi) \
+    && git clone --depth 42 $BR https://github.com/hiddenalpha/DeflateAndInflate.git . \
     && ./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
new file mode 100644
index 0000000..971c2e6
--- /dev/null
+++ b/contrib/build-using-docker/README.md
@@ -0,0 +1,60 @@
+
+Showcase how to build and install
+=================================
+
+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
+IMG=deflateandinflate-showcase:latest
+```
+
+## Make and install dockerimage
+
+```sh
+curl -sSL https://github.com/hiddenalpha/DeflateAndInflate/raw/master/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:?}" 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 `deflate --help` and/or `inflate --help`.
+
+```sh
+sudo docker run --rm -ti "${IMG:?}" sh
+```
+
+
+## Other targets
+
+The dockerfile is parameterized and should work for other systems too. For
+example to compile for debian we could use command like below. May set *IMG*
+differently if you need to keep multiple images.
+
+```sh
+curl -sSL https://github.com/hiddenalpha/DeflateAndInflate/raw/master/contrib/build-using-docker/Dockerfile | sudo docker build . -f - -t "${IMG:?}" \
+    --build-arg PARENT_IMAGE=debian:buster-20220622-slim \
+    --build-arg PKGS_TO_ADD="curl gcc git make libc-dev ca-certificates tar zlib1g-dev" \
+    --build-arg PKGS_TO_DEL="curl gcc git make libc-dev zlib1g-dev" \
+    --build-arg PKGINIT="apt-get update" \
+    --build-arg PKGADD="apt-get install -y --no-install-recommends" \
+    --build-arg PKGDEL="apt-get purge -y" \
+    --build-arg PKGCLEAN="apt-get clean"
+```
+