dockerfiles: Allow passing arbitrary arguments to build.sh

To allow customizing the arguments passed to docker/podman build(x)
beyond just the platform, modify build.sh to pass all its arguments
through to the build command.

For the platform case, this means it is now necessary to pass
"--platform linux/arm64" instead of just "linux/arm64" so modify
README.md to reflect this.

This change also has the effect of automatically using buildx if
supported, even if no arguments are passed, so move the information
about buildx further up in the text. The link to podman's buildx is
dropped as (unlike Docker) "podman buildx" is just an alias for
"podman build".

Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>

Author: hoyes

dockerfiles/README.rst

@@ -27,8 +27,9 @@ Example showing how to build labgrid-client image:
 Using `BuildKit <https://docs.docker.com/develop/develop-images/build_enhancements/>`_
 is recommended to reduce build times.
 
-You can also choose to build all 3 images,
-with the included script.
+You can also choose to build all 3 images with the included script. The script
+will automatically use `docker buildx
+<https://docs.docker.com/engine/reference/commandline/buildx/>`` if available.
 
 .. code-block:: bash
 
@@ -43,15 +44,13 @@ The script supports ``podman`` as well.
    $ ./dockerfiles/build.sh
 
 It builds for the native platform by default. However, building
-for foreign platforms is also supported using `docker buildx
-<https://docs.docker.com/build/building/multi-platform/>` or `podman
-buildx <https://docs.podman.io/en/latest/markdown/podman-build.1.html>`
-by passing the platform of choice, e.g. `linux/arm64`.
+for foreign platforms is also supported by passing the platform(s) of choice,
+e.g. `linux/arm64` as an additional argument.
 
 .. code-block:: bash
 
    $ pip install --upgrade setuptools_scm
-   $ ./dockerfiles/build.sh linux/arm64
+   $ ./dockerfiles/build.sh --platform linux/arm64
 
 
 Usage

dockerfiles/build.sh

@@ -53,12 +53,14 @@ perform_regular_build() {
     docker_cmd="${1}"
     script_dir="${2}"
     version="${3}"
+    extra_args=("${@:4}")
 
     log_info "building for native platform only."
 
     for t in client exporter coordinator; do
         "${docker_cmd}" build --build-arg VERSION="${version}" \
-            --target labgrid-${t} -t labgrid-${t}:latest -f "${script_dir}/Dockerfile" .
+            --target labgrid-${t} -t labgrid-${t}:latest -f "${script_dir}/Dockerfile" \
+            "${extra_args[@]}" .
     done
 }
 
@@ -67,16 +69,17 @@ perform_docker_buildx_build() {
     docker_cmd="${1}"
     script_dir="${2}"
     version="${3}"
+    extra_args=("${@:4}")
 
     for t in client exporter coordinator; do
-        "${docker_cmd}" buildx build --platform "${platform}" --build-arg VERSION="${version}" \
-            --target labgrid-${t} -t labgrid-${t}:latest -f "${script_dir}/Dockerfile" .
+        "${docker_cmd}" buildx build --build-arg VERSION="${version}" \
+            --target labgrid-${t} -t labgrid-${t}:latest -f "${script_dir}/Dockerfile" \
+            "${extra_args[@]}" .
     done
 }
 
 main() {
-    local platform script_dir version
-    platform="${1}"
+    local script_dir version
 
     if ! has_docker && ! has_podman; then
         die "Neither docker nor podman could be found."
@@ -88,11 +91,11 @@ main() {
 
     cd "${script_dir}/.." || die "Could not cd into repo root dir"
 
-    if has_buildx "${docker_cmd}" && [ -n "${platform}" ]; then
-        perform_docker_buildx_build "${docker_cmd}" "${script_dir}" "${version}" "${platform}"
+    if has_buildx "${docker_cmd}"; then
+        perform_docker_buildx_build "${docker_cmd}" "${script_dir}" "${version}" "${@}"
     else
-        perform_regular_build "${docker_cmd}" "${script_dir}" "${version}"
+        perform_regular_build "${docker_cmd}" "${script_dir}" "${version}" "${@}"
     fi
 }
 
-main "${1}"
+main "${@}"