Update Dockerfile

Dockerfile

@@ -1,8 +1,5 @@
 FROM python:3.11-slim
 
-# Declare your environment variables with the ARG directive
-ARG HF_TOKEN
-
 # Install build dependencies for packages such as uvicorn[standard]
 RUN apt-get update && \
     apt-get install -y --no-install-recommends build-essential git && \
@@ -26,9 +23,14 @@ COPY --chown=user requirements.txt .
 RUN pip install --no-cache-dir --upgrade pip && \
     pip install --no-cache-dir -r requirements.txt
 
-# Pre-download the SentenceTransformer embedding model to avoid runtime cold-starts
-# You can use them like environment variables
-RUN python - <<'PY'
+# Pre-download the gated embedding model to avoid first-request latency.
+# Requires a Hugging Face token supplied at build-time via --build-arg HF_TOKEN=...
+ARG HF_TOKEN
+RUN if [ -z "$HF_TOKEN" ]; then \
+        echo "HF_TOKEN build arg missing. Supply --build-arg HF_TOKEN=hf_xxx when building." >&2; \
+        exit 1; \
+    fi && \
+    HF_TOKEN="$HF_TOKEN" python - <<'PY'
 import os
 from sentence_transformers import SentenceTransformer