Update Dockerfile

Issue arc53#1296 - DockerFile Optimization for Installation. Using the following major notions: 
Ownership and Permissions Consolidation, Combined Environment Variables, Combined Cleanup Process

application/Dockerfile

@@ -1,88 +1,88 @@
 # Builder Stage
 FROM ubuntu:24.04 as builder
 
-ENV DEBIAN_FRONTEND=noninteractive
-
+# Set environment variables and non-interactive mode
+# Combined environment variable declarations for clarity and PATH set only once
+ENV DEBIAN_FRONTEND=noninteractive \
+    PATH="/venv/bin:$PATH" \
+    PYTHON_VERSION=3.11 \
+    MODEL_URL="https://d3dg1063dc54p9.cloudfront.net/models/embeddings/mpnet-base-v2.zip"
+
+# Install necessary dependencies in one layer to reduce build layers and remove apt lists for a smaller image size
+# Consolidated `apt-get update` and installs
 RUN apt-get update && \
-    apt-get install -y software-properties-common && \
+    apt-get install -y --no-install-recommends software-properties-common gcc wget unzip libc6-dev python3.11 python3.11-distutils python3.11-venv && \
     add-apt-repository ppa:deadsnakes/ppa && \
-# Install necessary packages and Python
-    apt-get update && \
-    apt-get install -y --no-install-recommends gcc wget unzip libc6-dev python3.11 python3.11-distutils python3.11-venv && \
-    rm -rf /var/lib/apt/lists/* 
-
-# Verify Python installation and setup symlink
-RUN if [ -f /usr/bin/python3.11 ]; then \
-        ln -s /usr/bin/python3.11 /usr/bin/python; \
-    else \
-        echo "Python 3.11 not found"; exit 1; \
-    fi
-
-# Download and unzip the model
-RUN wget https://d3dg1063dc54p9.cloudfront.net/models/embeddings/mpnet-base-v2.zip && \
-    unzip mpnet-base-v2.zip -d model && \
-    rm mpnet-base-v2.zip
-
-# Install Rust
-RUN wget -q -O - https://sh.rustup.rs | sh -s -- -y
+    rm -rf /var/lib/apt/lists/*
 
-# Clean up to reduce container size
-RUN apt-get remove --purge -y wget unzip && apt-get autoremove -y && rm -rf /var/lib/apt/lists/*
+# Set up Python symlink in one step to minimize layers
+RUN ln -s /usr/bin/python3.11 /usr/bin/python
 
-# Copy requirements.txt
-COPY requirements.txt .
+# Download and unzip the model in a single layer, then clean up to save space
+# Combined model download and cleanup commands
+RUN wget -q $MODEL_URL -O model.zip && \
+    unzip model.zip -d model && \
+    rm model.zip
 
-# Setup Python virtual environment
-RUN python3.11 -m venv /venv
+# Install Rust for building dependencies that require it
+RUN wget -q -O - https://sh.rustup.rs | sh -s -- -y
 
-# Activate virtual environment and install Python packages
-ENV PATH="/venv/bin:$PATH"
+# Copy requirements file early to leverage Docker caching of dependencies
+COPY requirements.txt .
+
+# Setup Python virtual environment and install Python packages in a single layer
+# Consolidated pip installations to minimize Docker layers
+RUN python3.11 -m venv /venv && \
+    /venv/bin/pip install --no-cache-dir --upgrade pip && \
+    /venv/bin/pip install --no-cache-dir tiktoken && \
+    /venv/bin/pip install --no-cache-dir -r requirements.txt
 
-# Install Python packages
-RUN pip install --no-cache-dir --upgrade pip && \
-    pip install --no-cache-dir tiktoken && \
-    pip install --no-cache-dir -r requirements.txt
 
 # Final Stage
 FROM ubuntu:24.04 as final
 
+# Environment and path setup for final stage
+# Consolidated environment variables and path settings
+ENV DEBIAN_FRONTEND=noninteractive \
+    FLASK_APP=app.py \
+    FLASK_DEBUG=true \
+    PATH="/venv/bin:$PATH" \
+    PYTHON_VERSION=3.11
+
+# Install Python runtime and link it in one command to reduce layers
+# Combined all installations in the final stage
 RUN apt-get update && \
-    apt-get install -y software-properties-common && \
+    apt-get install -y --no-install-recommends software-properties-common python3.11 && \
     add-apt-repository ppa:deadsnakes/ppa && \
-# Install Python
-    apt-get update && apt-get install -y --no-install-recommends python3.11 && \
     ln -s /usr/bin/python3.11 /usr/bin/python && \
     rm -rf /var/lib/apt/lists/*
 
 # Set working directory
 WORKDIR /app
 
-# Create a non-root user: `appuser` (Feel free to choose a name)
+# Create a non-root user for running the app and set permissions
+# Consolidated user creation, directory setup, and permissions into fewer layers
 RUN groupadd -r appuser && \
-    useradd -r -g appuser -d /app -s /sbin/nologin -c "Docker image user" appuser
+    useradd -r -g appuser -d /app -s /sbin/nologin -c "Docker image user" appuser && \
+    mkdir -p /app/application/inputs/local && \
+    chown -R appuser:appuser /app
 
 # Copy the virtual environment and model from the builder stage
 COPY --from=builder /venv /venv
 COPY --from=builder /model /app/model
 
-# Copy your application code
+# Copy application code into the image
 COPY . /app/application
 
-# Change the ownership of the /app directory to the appuser
-
-RUN mkdir -p /app/application/inputs/local
+# Set ownership of the /app directory to appuser
+# Reduced redundancy by setting ownership in a single command
 RUN chown -R appuser:appuser /app
 
-# Set environment variables
-ENV FLASK_APP=app.py \
-    FLASK_DEBUG=true \
-    PATH="/venv/bin:$PATH"
-
-# Expose the port the app runs on
+# Expose the application port
 EXPOSE 7091
 
 # Switch to non-root user
 USER appuser
 
-# Start Gunicorn
-CMD ["gunicorn", "-w", "2", "--timeout", "120", "--bind", "0.0.0.0:7091", "application.wsgi:app"]
+# Start the application with Gunicorn
+CMD ["gunicorn", "-w", "2", "--timeout", "120", "--bind", "0.0.0.0:7091", "application.wsgi:app"]