Updating deploy script for using UV & CI

I've modified the deployment script so it will use UV now for the environment management. First, UV should be installed on the host server. 

I've modified the deploy script like this:

#!/usr/bin/env bash
set -Eeuo pipefail

# Flags
run_tests=false
run_collectstatic=false
python_version=""
env_path=""

usage() {
  cat <<EOF
Usage: $0 [-t] [-c] [-p <python_version>] [-e <env_path>]
  -t                    Run Django tests
  -c                    Run "collectstatic"
  -p <python_version>   Use a specific Python (e.g. 3.12, 3.13)
  -e <env_path>         Use a specific virtualenv directory (default: .venv)
                        (uv will honor VIRTUAL_ENV if set)
  -h                    Show this help
Examples:
  $0 -t
  $0 -c -p 3.13
  $0 -t -c -e venv -p 3.12
EOF
}

while getopts ":tcp:e:h" opt; do
  case "$opt" in
    t) run_tests=true ;;
    c) run_collectstatic=true ;;
    p) python_version="$OPTARG" ;;
    e) env_path="$OPTARG" ;;
    h) usage; exit 0 ;;
    \?) echo "Unknown option: -$OPTARG" >&2; usage; exit 1 ;;
    :)  echo "Option -$OPTARG requires an argument." >&2; usage; exit 1 ;;
  esac
done

export PATH="$HOME/.local/bin:$HOME/.cargo/bin:$PATH"
UV_BIN="${UV_BIN:-$(command -v uv || true)}"
if [[ -z "$UV_BIN" ]]; then
  echo "uv not found on PATH: $PATH" >&2
  exit 127
fi


# Make UV use a specific env directory if requested
if [[ -n "$env_path" ]]; then
  # uv respects VIRTUAL_ENV when set
  export VIRTUAL_ENV="$(realpath "$env_path")"
fi

prepare_env() {
  echo "==> Syncing environment with uv..."
  if [[ -n "$python_version" ]]; then
    echo "    Using Python $python_version"
    uv sync --python "$python_version"
  else
    uv sync
  fi
  echo "==> Interpreter in use:"
  uv run python -c 'import sys,platform; print(sys.executable); print(platform.python_version())'
}

# Run tasks
if $run_tests || $run_collectstatic; then
  prepare_env
fi

if $run_tests; then
  echo "==> Running tests..."
  # If your DB user needs CREATEDB for Django's test DB, grant it separately.
  if ! uv run python manage.py test; then
    echo "Tests failed! Aborting."
    exit 1
  fi
fi

if $run_collectstatic; then
  echo "==> Running collectstatic..."
  if ! uv run python manage.py collectstatic --noinput; then
    echo "collectstatic failed! Aborting."
    exit 1
  fi
fi
echo "==> Interpreter in use:"
uv run python -c 'import sys,platform; print(sys.executable); print(platform.python_version())'

echo "==> Reloading services..."
# Reload systemd and restart gunicorn units
systemctl daemon-reload
systemctl restart gunicorn.socket gunicorn.service
systemctl reload nginx

echo "Done."

First, set strict mode: 

set -Eeuo pipefail – “strict mode”:

• -E – error traps propagate into functions.

• -e – exit if any command fails.

• -u – treat unset variables as errors.

• pipefail – A pipeline fails if any part fails, not just the last command.

Second, added the usage function, so help can be called:

Third, I encountered a problem: when running the CI/CD pipeline, the root user did not see UV path, so I've added it in the script: 

export PATH="$HOME/.local/bin:$HOME/.cargo/bin:$PATH"

# This line adds two directories at the front of PATH:
#     $HOME/.local/bin – where tools like uv are often installed for your user.
#     $HOME/.cargo/bin – where Rust-installed tools live (also a common place for uv).
#     :$PATH at the end keeps the original PATH too.
# export makes this new PATH visible to any commands the script runs.

UV_BIN="${UV_BIN:-$(command -v uv || true)}"

# This line sets a variable UV_BIN that should contain the full path to the uv executable.

#    command -v uv
#      Asks the shell: “Where is the uv command?”
#      If found, it prints something like /home/user/.local/bin/uv.

#    || true
#      If command -v uv fails (no uv installed), the script won’t crash even if set -e is on. It              #      just returns an empty string instead of killing the script.

#    "${UV_BIN:- ... }"
#       If UV_BIN is already set (e.g. you ran UV_BIN=/usr/local/bin/uv ./restart.sh),
#       then keep that value.
#       Otherwise, use the result of command -v uv.

# So:
#  “If the caller already told me where uv is, use that. Otherwise, try to find uv in PATH and store #   its path in UV_BIN.”

if [[ -z "$UV_BIN" ]]; then
#  [[ -z "$UV_BIN" ]] – checks if UV_BIN is empty (zero-length string).
#      It will be empty if:
#         uv wasn’t found in PATH and you didn’t set UV_BIN manually.
  echo "uv not found on PATH: $PATH" >&2
#   If it is empty:
#      Print an error message.
#      >&2 sends it to stderr (error output), not normal stdout.
  exit 127
#    Stop the script with exit code 127. 
#     127 is the conventional “command not found” error code in shells.
#    So:
#      “If I still don’t know where uv is, fail early with a clear error and don’t continue.”
fi