Update Python dependency installer: add virtual environment setup to handle externally managed environments.

Author: flemming-n-larsen

sample-bots/python/assets/install-dependencies.sh

@@ -5,6 +5,7 @@
 # Behavior:
 # - Changes to the directory where this script resides
 # - If .deps_installed does not exist, installs requirements from requirements.txt
+# - Uses a virtual environment to avoid externally-managed-environment errors
 # - Only creates .deps_installed if installation succeeds
 # - Exits with non-zero code and message on failure
 
@@ -13,41 +14,82 @@ set -euo pipefail
 # Change to the directory where this script is located
 cd -- "$(dirname -- "$0")"
 
-# Helper to locate a working pip command
-find_pip() {
-  if command -v python3 >/dev/null 2>&1 && python3 -m pip --version >/dev/null 2>&1; then
-    echo "python3 -m pip"
-    return 0
-  fi
-  if command -v python >/dev/null 2>&1 && python -m pip --version >/dev/null 2>&1; then
-    echo "python -m pip"
-    return 0
-  fi
-  if command -v pip3 >/dev/null 2>&1; then
-    echo "pip3"
+# Helper to find a working Python command
+find_python() {
+  if command -v python3 >/dev/null 2>&1; then
+    echo "python3"
     return 0
   fi
-  if command -v pip >/dev/null 2>&1; then
-    echo "pip"
+  if command -v python >/dev/null 2>&1; then
+    echo "python"
     return 0
   fi
   return 1
 }
 
+# Helper to create and use virtual environment
+setup_venv() {
+  local python_cmd="$1"
+  local venv_dir="venv"
+
+  # Create virtual environment if it doesn't exist
+  if [ ! -d "$venv_dir" ]; then
+    echo "Creating virtual environment..."
+    if ! "$python_cmd" -m venv "$venv_dir"; then
+      echo "Error: Failed to create virtual environment. Make sure python3-venv is installed." >&2
+      echo "Try: sudo apt install python3-venv python3-full" >&2
+      exit 1
+    fi
+  fi
+
+  # Return the path to the venv pip
+  echo "$venv_dir/bin/pip"
+}
+
 if [ ! -f ".deps_installed" ]; then
   echo "Installing dependencies..."
 
-  if ! PIP_CMD=$(find_pip); then
-    echo "Error: pip not found. Please install Python and pip." >&2
+  if ! PYTHON_CMD=$(find_python); then
+    echo "Error: Python not found. Please install Python." >&2
     exit 1
   fi
 
-  if ${PIP_CMD} install -q -r requirements.txt; then
+  # Try to use system pip first, fall back to virtual environment on failure
+  PIP_CMD=""
+
+  # First, try to find system pip
+  if command -v python3 >/dev/null 2>&1 && python3 -m pip --version >/dev/null 2>&1; then
+    PIP_CMD="python3 -m pip"
+  elif command -v python >/dev/null 2>&1 && python -m pip --version >/dev/null 2>&1; then
+    PIP_CMD="python -m pip"
+  elif command -v pip3 >/dev/null 2>&1; then
+    PIP_CMD="pip3"
+  elif command -v pip >/dev/null 2>&1; then
+    PIP_CMD="pip"
+  fi
+
+  # Try system pip installation first
+  if [ -n "$PIP_CMD" ] && ${PIP_CMD} install -q -r requirements.txt 2>/dev/null; then
     # Create marker file to indicate dependencies are installed
     : > .deps_installed
-    echo "Dependencies installed."
+    echo "Dependencies installed using system pip."
   else
-    echo "Error: Failed to install dependencies." >&2
-    exit 1
+    # System pip failed (likely externally-managed-environment), use virtual environment
+    echo "System pip failed (likely externally managed environment). Using virtual environment..."
+
+    if ! VENV_PIP=$(setup_venv "$PYTHON_CMD"); then
+      echo "Error: Failed to setup virtual environment." >&2
+      exit 1
+    fi
+
+    if "$VENV_PIP" install -q -r requirements.txt; then
+      # Create marker file to indicate dependencies are installed
+      : > .deps_installed
+      echo "Dependencies installed in virtual environment."
+      echo "Note: Virtual environment created in ./venv directory"
+    else
+      echo "Error: Failed to install dependencies in virtual environment." >&2
+      exit 1
+    fi
   fi
 fi