chore: Update Dockerfile to use virtual environment for Python depend…

…encies and set app path

Dockerfile

@@ -1,29 +1,43 @@
-# Define the build argument with no default value
+# Global args
 ARG PYTHON_VERSION=3.10
+ARG APP_PATH=/app
+ARG VIRTUAL_ENV_PATH=.venv
 
 # Builder stage
 FROM python:${PYTHON_VERSION}-slim AS builder
 
+# Re-declare the ARG to use it in this stage
+ARG APP_PATH
+ARG VIRTUAL_ENV_PATH
+
 # hadolint ignore=DL3008
 RUN <<EOF
     apt-get update
     apt-get install --no-install-recommends -y git
 EOF
 
 # Set the working directory:
-WORKDIR /app
+WORKDIR ${APP_PATH}
+
+# Set a Virtual env
+RUN python3 -m venv "${APP_PATH}/${VIRTUAL_ENV_PATH}"
+ENV PATH="${APP_PATH}/${VIRTUAL_ENV_PATH}/bin:$PATH"
 
 # Copy and install dependencies:
-COPY requirements.lock ./
+COPY requirements.lock .
 RUN PYTHONDONTWRITEBYTECODE=1 pip install --no-cache-dir -r requirements.lock
 
 # Copy the application source code:
 COPY src .
 
 # Final stage
-FROM python:${PYTHON_VERSION}-slim
+FROM python:${PYTHON_VERSION}-slim as target
 
-# Define the build argument with a default value
+# Redeclare args
+ARG APP_PATH
+ARG VIRTUAL_ENV_PATH
+
+# Image args
 ARG REGISTRY="ghcr.io"
 ARG REPOSITORY="inean/dns-synchub"
 
@@ -33,10 +47,13 @@ LABEL image="${REGISTRY}/${REPOSITORY}"
 LABEL maintainer="Carlos Martín (github.com/inean)"
 
 # Set the working directory:
-WORKDIR /app
+WORKDIR ${APP_PATH}
+
+# Ensure venv is used
+ENV PATH="${APP_PATH}/${VIRTUAL_ENV_PATH}/bin:$PATH"
 
 # Copy dependencies and source code from the builder stage
-COPY --from=builder /app /app
+COPY --from=builder ${APP_PATH} ${APP_PATH}
 
 # Run the application:
 ENTRYPOINT ["python", "-m", "dns_synchub"]