Another approach

.github/workflows/build.yml

@@ -71,9 +71,12 @@ jobs:
                       build.json
                       .github/workflows/env.hcl
 
-            - name: Set output variables
+            - name: Set output image names
               id: bake_metadata
+              # bake-action metadata output has gotten too big, so we first write it
+              # to a file. See https://github.com/aiidalab/aiidalab-docker-stack/issues/491
               run: |
-                  .github/workflows/extract-image-names.sh | tee -a "${GITHUB_OUTPUT}" | awk -F'=' '{print $2}' | jq
-              env:
-                  BAKE_METADATA: ${{ steps.build-upload.outputs.metadata }}
+                  cat << EOF
+                  ${{ steps.build-upload.outputs.metadata }}
+                  EOF > bake_metadata.json
+                  .github/workflows/extract-image-names.sh bake_metadata.json | tee -a "${GITHUB_OUTPUT}" | tr -d 'images=' | jq

.github/workflows/extract-image-names.sh

@@ -48,8 +48,6 @@ set -euo pipefail
 # (e.g. BASE_IMAGE=ghcr.io/aiidalab/base@sha256:8e57a52b...)
 # and these are in turn read in the docker-compose.<target>.yml files for tests.
 
-# NOTE: BAKE_METADATA has gotten too large and cannot be passed directly as cmdline argument to avoid
-# "Argument list too long" BASH error, see: https://github.com/aiidalab/aiidalab-docker-stack/issues/491
-# Therefore we first need to parse the output from `env` command and pass it to jq via piped stdin
-images=$(env | grep -E "^BAKE_METADATA=" | tr -d 'BAKE_METADATA=' | jq -c '. as $base |[to_entries[] |{"key": (.key|ascii_upcase|sub("-"; "_"; "g") + "_IMAGE"), "value": [(.value."image.name"|split(",")[0]),.value."containerimage.digest"]|join("@")}] |from_entries')
+metadata_file=$1
+images=$(jq -c '. as $base |[to_entries[] |{"key": (.key|ascii_upcase|sub("-"; "_"; "g") + "_IMAGE"), "value": [(.value."image.name"|split(",")[0]),.value."containerimage.digest"]|join("@")}] |from_entries' $metadata_file)
 echo "images=$images"