Dockerfile: use Python venv, improve image size

Reduced size by ~180 MB:
```
 > d images | grep statusteam/logos-open-law
statusteam/logos-open-law            new                             e547a1a95495   24 hours ago    312MB
statusteam/logos-open-law            old                             c3d18cb98d82   45 hours ago    494MB
```

Signed-off-by: Jakub Sokołowski <jakub@status.im>

Dockerfile

@@ -1,53 +1,55 @@
-##########################################
-## build frontend
-##########################################
-FROM node:buster as front_build
-# FROM node as front_build
-RUN mkdir /front
-WORKDIR /front
-COPY . /front/
-RUN yarn
-RUN npx update-browserslist-db@latest -y
-RUN yarn css
-RUN yarn js
-
-
-FROM python:3.11-alpine
-
-# install build utils and dependencies
-RUN apk update && apk upgrade
-RUN apk add --no-cache pkgconfig \
-    gcc \
-    musl-dev \
-    libffi-dev \
-    && rm -rf /var/cache/apk/*
-
-
-# Add user app
-RUN python -m pip install -U pip
-RUN adduser -D app
-USER app
-WORKDIR /home/app
-
-# set environment varibles
-ENV PYTHONFAULTHANDLER 1
-ENV PYTHONUNBUFFERED 1
-ENV PYTHONHASHSEED random
-ENV PIP_NO_CACHE_DIR off
-ENV PIP_DISABLE_PIP_VERSION_CHECK on
-
-# install poetry
-RUN pip install --user poetry
-ENV PATH="/home/app/.local/bin:${PATH}"
-
-# install app dependencies
-COPY --chown=app:app poetry.lock .
-COPY --chown=app:app pyproject.toml .
-COPY --chown=app:app poetry.toml .
-
-RUN poetry install --no-dev --no-interaction --no-ansi
-# add gunicorn
-RUN poetry add gunicorn
-
-COPY --chown=app:app . .
-COPY --chown=app:app --from=front_build /front/app/static ./app/static
+# frontent builder stage ---------------------------------------------
+FROM node:20.3-alpine3.18 as frontend_builder
+
+RUN mkdir /app
+WORKDIR /app
+COPY . /app
+
+RUN yarn
+RUN npx update-browserslist-db@latest -y
+RUN yarn css
+RUN yarn js
+
+# backend builder stage ----------------------------------------------
+FROM python:3.11-alpine as backend_builder
+
+ENV VIRTUAL_ENV=/app/venv
+ENV PATH="$VIRTUAL_ENV/bin:$PATH"
+ENV PYTHONFAULTHANDLER=1
+ENV PYTHONUNBUFFERED=1
+ENV PYTHONHASHSEED=random
+ENV PIP_NO_CACHE_DIR=off
+ENV PIP_DISABLE_PIP_VERSION_CHECK=on
+
+RUN mkdir /app
+WORKDIR /app
+COPY . /app
+
+RUN apk update \
+ && apk add --no-cache pkgconfig gcc musl-dev libffi-dev \
+ && rm -rf /var/cache/apk/*
+
+RUN python -m venv $VIRTUAL_ENV \
+ && pip install poetry
+
+RUN poetry install --only main --no-interaction --no-ansi \
+ && poetry add gunicorn
+
+# final image stage --------------------------------------------------
+FROM python:3.11-alpine as final
+
+ENV VIRTUAL_ENV=/app/venv
+ENV PATH="$VIRTUAL_ENV/bin:$PATH"
+
+RUN mkdir /app
+WORKDIR /app
+
+RUN adduser -D app
+USER app
+
+RUN pip install poetry
+
+COPY --chown=app:app --from=frontend_builder /app/app/static ./static
+COPY --chown=app:app --from=backend_builder  /app ./
+
+ENTRYPOINT ["/bin/sh", "./start_server.sh"]

start_server.sh

@@ -4,4 +4,4 @@ poetry run flask db upgrade
 # echo Run app
 # flask run -h 0.0.0.0
 echo Run app server
-poetry run gunicorn -w 4 -b 0.0.0.0 'wsgi:app'
+poetry run gunicorn -w 4 -b 0.0.0.0 'wsgi:app' $@