misc: Make base optional

Author: JDBetteridge

.github/actions/docker-build/action.yaml

@@ -13,8 +13,7 @@ inputs:
     required: true
   base:
     description: "Base docker image to build on top of"
-    required: true
-    default: "devitocodes/bases:cpu-gcc"
+    default: ""
 
 outputs:
   unique:
@@ -40,15 +39,5 @@ runs:
           --pull \
           --file ${{ inputs.file }} \
           --tag ${{ inputs.tag }}_${{ steps.uniquetag.outputs.unique }} \
-          --build-arg base=${{ inputs.base }} \
+          ${${{ inputs.base }}:+--build-arg base=${{ inputs.base }}} \
           .
-
-# Do we need to be more specific?
-#~ docker buildx build . \
-  #~ --builder "${RUNNER_NAME// /_}" \
-  #~ --load \
-  #~ --label ci-run="$GITHUB_RUN_ID" \
-  #~ --rm --pull \
-  #~ --file docker/Dockerfile.devito \
-  #~ --tag "${DOCKER_IMAGE}" \
-  #~ --build-arg base="${{ matrix.base }}"

docker/Dockerfile.devito

@@ -3,7 +3,6 @@
 ##############################################################
 
 # Base image with compilers
-# Update default in .github/actions/docker-build if this value ever changes
 ARG base=devitocodes/bases:cpu-gcc
 
 FROM $base AS builder