add docker image optimization (#3727)

* add docker image optimization
* flip copy for even more caching
* fix pyproject install bug

scanner/templates/python-docker/.dockerignore

@@ -2,3 +2,4 @@ fly.toml
 .git/
 __pycache__/
 .envrc
+.venv/

scanner/templates/python-docker/Dockerfile

@@ -1,45 +1,34 @@
-FROM python:{{ .pyVersion }} AS builder
+FROM python:{{ .pyVersion }}-bookworm AS builder
 
 ENV PYTHONUNBUFFERED=1 \
     PYTHONDONTWRITEBYTECODE=1
-
 WORKDIR /app
-COPY . .
 
 {{ if .pipenv -}}
-
 ENV PIPENV_VENV_IN_PROJECT=1 \
     PIPENV_CUSTOM_VENV_NAME=.venv
 RUN pip install pipenv
+COPY Pipfile Pipfile.lock ./
 RUN pipenv install
-
 {{ else if .poetry -}}
-
 RUN pip install poetry
 RUN poetry config virtualenvs.in-project true
+COPY pyproject.toml poetry.lock ./
 RUN poetry install
-
 {{ else if .pep621 -}}
-
-RUN python -m venv .venv && \
-    . .venv/bin/activate && \
-    pip install --upgrade pip && \
-    pip install .
-
+RUN python -m venv .venv
+COPY pyproject.toml ./
+RUN .venv/bin/pip install .
 {{ else if .pip }}
-
-RUN python -m venv .venv && \
-    . .venv/bin/activate && \
-    pip install --upgrade pip && \
-    pip install -r requirements.txt
-
+RUN python -m venv .venv
+COPY requirements.txt ./
+RUN .venv/bin/pip install -r requirements.txt
 {{ end -}}
 
-FROM python:{{ .pyVersion }}-slim
-
+FROM python:{{ .pyVersion }}-slim-bookworm
 WORKDIR /app
-COPY --from=builder /app .
-
+COPY --from=builder /app/.venv .venv/
+COPY . .
 {{ if .flask -}}
 CMD ["/app/.venv/bin/flask", "run", "--host=0.0.0.0", "--port=8080"]
 {{ else if .fastapi -}}