[UPDT] Using docker multi-stage builds to reduce docker image's size (#925)

* [UPDT] Using docker multi-stage builds to reduce docker image's size

* [FIX] Updating WORKDIR for consistency

Dockerfile

@@ -1,17 +1,26 @@
-FROM python:3.10-slim-bullseye
+FROM python:3.10-slim-bullseye AS builder
 
 ENV PYTHONUNBUFFERED=1
 
-RUN apt-get update && apt-get install -y libcairo2-dev gcc
+RUN apt-get update && apt-get install -y --no-install-recommends libcairo2-dev gcc && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app/
 
+COPY requirements.txt .
+RUN pip install --no-cache-dir --prefix=/install -r requirements.txt
+
+FROM python:3.10-slim-bullseye AS runtime
+
+ENV PYTHONUNBUFFERED=1
+
+WORKDIR /app/
+
+COPY --from=builder /install /usr/local
+
 COPY . .
 
 RUN chmod +x /app/entrypoint.sh
 
-RUN pip install -r requirements.txt
-
 EXPOSE 8000
 
 CMD ["python3", "manage.py", "runserver"]