map docker sock, var expansion

.woodpecker/main.yml

@@ -1,13 +1,13 @@
 variables:
   &vars
-    REGISTRY=code.balsillie.net
-    REGISTRY_USER=michael
-    ORGANIZATION=containers
-    SOURCE_ORGANIZATION=mirrors
-    REPO=matrix-service-synapse
-    BUILD_ARGS="PYTHON_VERSION=3.10"
-    DOCKERFILE="docker/Dockerfile"
-    CONTEXT=.
+    - REGISTRY=code.balsillie.net
+    - REGISTRY_USER=michael
+    - ORGANIZATION=containers
+    - SOURCE_ORGANIZATION=mirrors
+    - REPO=matrix-service-synapse
+    - BUILD_ARGS="PYTHON_VERSION=3.10"
+    - DOCKERFILE="docker/Dockerfile"
+    - CONTEXT=.
 
 workspace:
   base: /git
@@ -25,27 +25,31 @@ pipeline:
       - /bin/bash check-tag.sh
   clone-source:
     image: docker:git
-    commands: 
-      - *vars
-      - git clone https://$REGISTRY/$SOURCE_ORGANIZATION/$REPO.git /git/$REPO
-      - cd /git/$REPO
+    environment:
+      *vars
+    commands:
+      - git clone https://${REGISTRY}/${SOURCE_ORGANIZATION}/${REPO}.git /git/${REPO}
+      - cd /git/${REPO}
       - git checkout $TAG
   docker-build:
     image: docker:latest
     secrets: 
       - source: REGISTRY_PASSWORD
         target: REGISTRY_PASSWORD
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock
+    environment:
+      *vars
     commands:
-      - *vars
       - export DOCKER_BUILDKIT=1
-      - cd /git/$REPO
-      - echo $REGISTRY_PASSWORD | docker login $REGISTRY -u $REGISTRY_USER --password-stdin
+      - cd /git/${REPO}
+      - echo $REGISTRY_PASSWORD | docker login ${REGISTRY} -u ${REGISTRY_USER} --password-stdin
       - docker build
-        -t $REGISTRY/$ORGANIZATION/$REPO:$TAG
-        -t $REGISTRY/$ORGANIZATION/$REPO:$(date +%F)
-        -t $REGISTRY/$ORGANIZATION/$REPO:latest
+        -t ${REGISTRY}/${ORGANIZATION}/${REPO}:$TAG
+        -t ${REGISTRY}/${ORGANIZATION}/${REPO}:$(date +%F)
+        -t ${REGISTRY}/${ORGANIZATION}/${REPO}:latest
         --pull
-        --build-arg $BUILD_ARGS
-        -f $DOCKERFILE
-        $CONTEXT
-      - docker push $REGISTRY/$ORGANIZATION/$REPO:latest
+        --build-arg ${BUILD_ARGS}
+        -f $}DOCKERFILE}
+        ${CONTEXT}
+      - docker push -a ${REGISTRY}/${ORGANIZATION}/${REPO}