createEnv.sh

#!/usr/bin/env bash

#
#   Copyright 2026 Deutsches Zentrum für Luft- und Raumfahrt e.V.
#
#   Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.
#


# check if a requirements file name was passed as an argument
REQ_FILE=${1:-requirements.txt}
VENV_NAME=${2:-target/venv}
PYTHON=${3:-python3}
CLIENTDIR=${4:-./target/src}

VENV_ACTIVATE_SCRIPT="$VENV_NAME/bin/activate"
MAX_SLEEP_SECONDS=300
LOCK_FILE=$VENV_NAME/.lock

createEnv() {
  # create venv
  "$PYTHON" -m venv "$VENV_NAME" || exit 1

  # create lock file so that on parallel execution only one call will
  # execute environment creation (others just wait until .lock file is gone)
  touch "$LOCK_FILE"

  # activate virtual environment
  . "$VENV_ACTIVATE_SCRIPT"  || exit 10

  # install dependencies
  pip install -r "$REQ_FILE" || exit 1

  # deactivate environment
  deactivate
  
  # trigger wmp-external-task-api client generation if not present
  CLIENT_IN_SRC="src/de/dlr/wmp/generated"
    
  if [ ! -d ${CLIENT_IN_SRC} ]; then
    ./generateClient.sh "${VENV_NAME}" "${CLIENTDIR}/de/dlr/wmp/generated"
    # (re-)create symlink for direct execution
    rm -f "${CLIENT_IN_SRC}"
    ln -s "$(readlink -f "${CLIENTDIR}/de/dlr/wmp/generated")" "${CLIENT_IN_SRC}"
  fi
  
  # release lock, so that other scripts can continue
  rm "$LOCK_FILE"
}

resetAndRetry() {
  # release lock, so that other scripts (and this) can continue
  rm "$LOCK_FILE"
  creatEnvOrAwaitCreation
}

waitForEnvCreationComplete() {
  # wait for lock and skip env creation (because env is already created by parallel call)
  while [[ -f "$LOCK_FILE" && $MAX_SLEEP_SECONDS -gt 0 ]]; do
    sleep 1
    ((MAX_SLEEP_SECONDS--))
  done
  # check if run in timeout if timeout, then trigger creatEvOrAwaitCreation
  if [[ ! $MAX_SLEEP_SECONDS -le 0 ]]; then
    creatEnvOrAwaitCreation
  fi
}

creatEnvOrAwaitCreation() {
  # check if environment is present (and maybe wait until env creation of parallel execution finishes)
  # or else create environment
  if [[ -d "$VENV_NAME" ]]; then
    echo "environment folder '$VENV_NAME' already exists: checking for lock file..."

    # check if other process is already creating this environment (lock file exists)
    if [[ -f "$LOCK_FILE" ]]; then
      # check if lock file is older than 5 minutes (assuming environment creation of parallel exec might have failed)
      if [ -n "$(find "$LOCK_FILE" -prune -mmin +5)" ]; then
        echo "lockfile to old, assuming failed environment creation, retry create environment"
        resetAndRetry
      else
        echo "lockfile present: await environment creation..."
        # wait for lock and skip env creation (because env is already created by parallel call)
        waitForEnvCreationComplete
      fi
    else
      echo "environment '$VENV_NAME' already exists and has no lock file: skip creation..."
    fi

  else
    echo "creating environment..."
    createEnv
  fi
}

creatEnvOrAwaitCreation