Improve db readiness and build args parsing

.github/workflows/docker-build-publish.yml

@@ -18,6 +18,8 @@ on:
         required: false
         type: string
         default: ""
+        description: >
+          Multiline build args, one per line: KEY=VALUE (values may include spaces)
 
       env:
         description: >
@@ -121,17 +123,21 @@ jobs:
           BUILD_ARG_FLAGS=()
           BUILD_ARGS_JSON="{}"
           if [ -n "$BUILD_ARGS" ]; then
-            for arg in $BUILD_ARGS; do
-              if [[ "$arg" != *=* ]]; then
-                echo "Invalid build arg: $arg" >&2
+            while IFS= read -r line; do
+              trimmed="${line#"${line%%[![:space:]]*}"}"
+              trimmed="${trimmed%"${trimmed##*[![:space:]]}"}"
+              [ -z "$trimmed" ] && continue
+              case "$trimmed" in \#*) continue;; esac
+              if [[ "$trimmed" != *=* ]]; then
+                echo "Invalid build arg: $trimmed" >&2
                 exit 1
               fi
-              BUILD_ARG_FLAGS+=(--build-arg "$arg")
+              BUILD_ARG_FLAGS+=(--build-arg "$trimmed")
 
-              key="${arg%%=*}"
-              val="${arg#*=}"
+              key="${trimmed%%=*}"
+              val="${trimmed#*=}"
               BUILD_ARGS_JSON=$(jq --arg k "$key" --arg v "$val" '. + {($k): $v}' <<<"$BUILD_ARGS_JSON")
-            done
+            done <<< "$BUILD_ARGS"
           fi
 
           while read -r group; do