backend was missing a dependency

applications/landlord_description_overrides/handler.py

@@ -120,8 +120,9 @@ def handler(
 ) -> dict[str, int]:
     trigger = LandlordDescriptionOverridesTriggerBody.model_validate(body)
 
-    # The classifier reads the ORIGINAL upload (raw landlord headers), so the S3
+    # The classifier reads a dedicated CSV of the classifier columns (raw
-    # bucket comes from the trigger URI rather than a fixed env var.
+    # landlord headers preserved), converted from the upload by the frontend, so
+    # the S3 bucket comes from the trigger URI rather than a fixed env var.
     bucket, _key = parse_s3_uri(trigger.s3_uri)
 
     # boto3.client is overloaded per-service in the installed stubs; cast to Any
@@ -136,7 +137,7 @@ def handler(
         csv_client, bucket
     )
 
-    # Raw rows, not load_batch: the original upload carries the description
+    # Raw rows, not load_batch: the classifier CSV carries the description
     # columns but not the canonical address/postcode columns load_batch requires.
     rows = csv_client.read_rows(trigger.s3_uri)
 

backend/address2UPRN/handler/Dockerfile

@@ -32,6 +32,9 @@ RUN pip install --no-cache-dir -r requirements.txt
 COPY utils/ utils/
 COPY backend/ backend/
 COPY datatypes/ datatypes/
+# main.py imports infrastructure.epc_client.epc_client_service (EpcClientService);
+# without this the lambda fails at init with "No module named 'infrastructure'".
+COPY infrastructure/ infrastructure/
 
 # Copy the handler
 COPY backend/address2UPRN/main.py .