Add support for multi-arch Docker containers

.gitlab-ci.yml

@@ -1,17 +1,34 @@
-image: docker:latest
+# Docker Hub version e.g. here https://github.com/oofnikj/nuttssh/blob/master/.gitlab-ci.yml
+image: oofnik/docker:buildx
 
 variables:
-  DOCKER_DRIVER: overlay2
-  IMAGE_TAG: $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_NAME
+  PLATFORM: linux/amd64,linux/arm/v7
+  CI_IMAGE: $CI_REGISTRY_IMAGE
 
 services:
   - docker:dind
 
-build:
+before_script:
+  - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+  - docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
+  - docker buildx create --use
+
+build-master:
   stage: build
   retry: 2
   script:
-    - docker login -u gitlab-ci-token -p $CI_JOB_TOKEN $CI_REGISTRY
-    - docker build -t $IMAGE_TAG .
-    - docker push $IMAGE_TAG
+    - docker buildx build --push -t "$CI_IMAGE"
+      --platform "$PLATFORM" --cache-from "$CI_IMAGE"
+      --build-arg BUILDKIT_INLINE_CACHE=1 .
+  only:
+    - master
 
+build-feature:
+  stage: build
+  retry: 2
+  script:
+    - docker buildx build --push -t "$CI_IMAGE:$CI_COMMIT_REF_SLUG"
+      --platform "$PLATFORM" --cache-from "$CI_IMAGE:$CI_COMMIT_REF_SLUG"
+      --build-arg BUILDKIT_INLINE_CACHE=1 .
+  except:
+    - master