CI: Create docker image with musl binary

.gitlab-ci.yml

@@ -1,5 +1,6 @@
 stages:
   - build
+  - build docker image
   - test
   - upload artifacts
 
@@ -212,6 +213,46 @@ build:cargo-deb:x86_64-unknown-linux-gnu:
 
 
 
+# --------------------------------------------------------------------- #
+#  Create and publish docker image                                      #
+# --------------------------------------------------------------------- #
+
+.docker-shared-settings:
+  stage: "build docker image"
+  needs: []
+  interruptible: true
+  image:
+    name: "gcr.io/kaniko-project/executor:debug"
+    entrypoint: [""]
+  tags: ["docker"]
+  variables:
+    # Configure Kaniko Caching: https://cloud.google.com/build/docs/kaniko-cache
+    KANIKO_CACHE_ARGS: "--cache=true --cache-copy-layers=true --cache-ttl=120h --cache-repo $CI_REGISTRY_IMAGE/kaniko-ci-cache"
+  before_script:
+    - "mkdir -p /kaniko/.docker"
+    - 'echo "{\"auths\":{\"$CI_REGISTRY\":{\"username\":\"$CI_REGISTRY_USER\",\"password\":\"$CI_REGISTRY_PASSWORD\"}}}" > /kaniko/.docker/config.json'
+
+
+# Build a docker image by packaging up the x86_64-unknown-linux-musl binary into an alpine image
+build:docker:main:
+  extends: .docker-shared-settings
+  needs:
+    - "build:cargo:x86_64-unknown-linux-musl"
+  script:
+    - >
+      /kaniko/executor
+      $KANIKO_CACHE_ARGS
+      --context $CI_PROJECT_DIR
+      --build-arg CREATED=$(date -u +'%Y-%m-%dT%H:%M:%SZ')
+      --build-arg VERSION=$(grep -m1 -o '[0-9].[0-9].[0-9]' Cargo.toml)
+      --build-arg "GIT_REF=$CI_COMMIT_REF_NAME"
+      --dockerfile "$CI_PROJECT_DIR/docker/ci-binaries-packaging.Dockerfile"
+      --destination "$CI_REGISTRY_IMAGE/conduit:latest"
+      --destination "$CI_REGISTRY_IMAGE/conduit:alpine"
+      --destination "$CI_REGISTRY_IMAGE/conduit:commit-$CI_COMMIT_SHORT_SHA"
+  rules:
+    - if: '$CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH'
+
 
 # --------------------------------------------------------------------- #
 #  Store binaries as package so they have download urls                 #