Update Dockerfile

Dockerfile

@@ -1,31 +1,32 @@
-FROM python:3.10
+FROM python:3.10-slim
 
-### Set up user with permissions
-# Set up a new user named "user" with user ID 1000
-RUN useradd -m -u 1000 user
+# 1) Install system deps (Graphviz provides `dot`)
+USER root
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    graphviz \
+    && rm -rf /var/lib/apt/lists/*
 
-# Switch to the "user" user
-USER user
+# 2) Create non-root user
+RUN useradd -m -u 1000 user
 
-# Set home to the user's home directory
 ENV HOME=/home/user \
     PATH=/home/user/.local/bin:$PATH
 
-# Set the working directory to the user's home directory
 WORKDIR $HOME/app
 
-# Copy the current directory contents into the container at $HOME/app setting the owner to the user
-COPY --chown=user . $HOME/app
+# 3) Copy only requirements first for better caching
+COPY requirements.txt $HOME/app/requirements.txt
+RUN pip3 install --no-cache-dir -r requirements.txt
 
-### Set up app-specific content
-COPY requirements.txt requirements.txt
-RUN pip3 install -r requirements.txt
+# 4) Copy the rest of the app
+COPY . $HOME/app
 
-COPY . .
+# 5) Fix ownership (no 777 needed)
+RUN chown -R user:user $HOME/app
 
-### Update permissions for the app
-USER root
-RUN chmod 777 ~/app/*
 USER user
 
+# Optional: sanity check during build (remove later if you want)
+# RUN which dot && dot -V
+
 CMD ["python", "main.py"]