feat(ci): Build the Docker image in GitHub Actions CI

.dockerignore

@@ -0,0 +1,3 @@
+.git
+LICENSE
+README.md

.github/workflows/docker-image.yml

@@ -0,0 +1,30 @@
+name: "Docker Image CI"
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  build:
+    env:
+      RUNS_ON: "ubuntu-20.04"
+    runs-on: "ubuntu-20.04"
+    steps:
+      - name: "Build Docker Image"
+        uses: docker/build-push-action@v5
+        with:
+          load: true
+          tags: "distcc-docker:${{ env.RUNS_ON }}"
+      - name: "Simple test"
+        run: |
+          docker run \
+            --init \
+            --rm \
+            "distcc-docker:${{ env.RUNS_ON }}"
+            --jobs $(nproc) \
+            -- \
+            bash -c \
+              "ps fauxw; " \
+              "/usr/bin/ls -alh .; " \
+              "/usr/bin/ls -alh /var/log; " \
+              "cat /var/log/*;"

Dockerfile

@@ -32,13 +32,11 @@ ENV \
   LC_ALL="en_US.UTF-8"
 
 
-COPY etc/ /etc/
-COPY usr/ /usr/
-
-
 # Set to non-zero if the compilers should only be installed into the container,
 # and not immediately baked into the image itself.
 ARG LAZY_COMPILERS=0
+
+COPY usr/local/sbin/install-compilers.sh /usr/local/sbin/install-compilers.sh
 RUN \
   if [ "x$LAZY_COMPILERS" = "x0" ]; \
   then \
@@ -67,6 +65,10 @@ RUN echo "Creating service user: $USERNAME ..." >&2 && \
   chmod -v 444 "/var/lib/distcc/distcc.user"
 
 
+COPY etc/ /etc/
+COPY usr/ /usr/
+
+
 # Expose the DistCC server's normal job and statistics subservice port.
 # Custom ports to be used on the host machine should be managed via Docker.
 EXPOSE \

usr/local/sbin/container-main.sh

@@ -317,7 +317,7 @@ if [ "$EXEC_CUSTOM" -eq 1 ]; then
     echo "[...] distcc service is running." >&2
   fi
 
-  custom_command $@
+  custom_command "$@"
   EXIT_CODE=$?
 
   atexit