build images on prs that touch docker stuff

.github/workflows/docker.yaml

@@ -58,13 +58,23 @@ jobs:
         GIT_SHA=$(echo ${{ github.sha }} | cut -c1-7)
         echo "IMAGE_TAG=${GIT_SHA}" >> ${GITHUB_ENV}
 
+        if [ "${{ github.event_name }}" == "push" ]; then
+          echo "Triggered by push event."
+          PROD_REPO="mosaicml/llm-foundry"
+          IMAGE_TAG=${PROD_REPO}:${{matrix.name}}-${GIT_SHA},${PROD_REPO}:${{matrix.name}}-latest
+          IMAGE_CACHE="${PROD_REPO}:${{matrix.name}}-buildcache"
+        elif [ "${{ github.event_name }}" == "pull_request" ]; then
+          echo "Triggered by pull_request event."
+          STAGING_REPO="mosaicml/ci-staging"
+          IMAGE_TAG=${STAGING_REPO}:${{matrix.name}}-${GIT_SHA}
+          IMAGE_CACHE="${STAGING_REPO}:${{matrix.name}}-buildcache"
+
     - name: Build and Push the Docker Image
       uses: docker/build-push-action@v3
       with:
         context: .
-        tags: mosaicml/llm-foundry:${{ matrix.name }}-latest,
-          mosaicml/llm-foundry:${{ matrix.name }}-${{ env.IMAGE_TAG }}
+        tags: ${{ env.IMAGE_TAG }}
         push: true
-        cache-from: type=registry,ref=mosaicml/llm-foundry:${{ matrix.name }}-buildcache
-        cache-to: type=registry,ref=mosaicml/llm-foundry:${{ matrix.name }}-buildcache,mode=max
+        cache-from: type=registry,ref=${{ env.IMAGE_CACHE }}
+        cache-to: type=registry,ref=${{ env.IMAGE_CACHE }},mode=max
         build-args: BASE_IMAGE=${{ matrix.base_image }}