[mod] webapp.py: update engines initialization condition

from searx.webutils import (

    UnicodeWriter, highlight_content, get_resources_directory,

    get_static_files, get_result_templates, get_themes,

    prettify_url, new_hmac

    prettify_url, new_hmac, is_flask_run_cmdline

)

from searx.webadapter import get_search_query_from_webapp, get_selected_categories

from searx.utils import html_to_text, gen_useragent, dict_subset, match_language

app.jinja_env.add_extension('jinja2.ext.loopcontrols')

app.secret_key = settings['server']['secret_key']

if not searx_debug \

   or os.environ.get("WERKZEUG_RUN_MAIN") == "true" \

   or os.environ.get('UWSGI_ORIGINAL_PROC_NAME') is not None:

# see https://flask.palletsprojects.com/en/1.1.x/cli/

# True if "FLASK_APP=searx/webapp.py FLASK_ENV=development flask run"

flask_run_development = \

    os.environ.get("FLASK_APP") is not None\

    and os.environ.get("FLASK_ENV") == 'development'\

    and is_flask_run_cmdline()

# True if reload feature is activated of werkzeug, False otherwise (including uwsgi, etc..)

#  __name__ != "__main__" if searx.webapp is imported (make test, make docs, uwsgi...)

# see run() at the end of this file : searx_debug activates the reload feature.

werkzeug_reloader = flask_run_development or (searx_debug and __name__ == "__main__")

# initialize the engines except on the first run of the werkzeug server.

if not werkzeug_reloader\

   or (werkzeug_reloader and os.environ.get("WERKZEUG_RUN_MAIN") == "true"):

    initialize_engines(settings['engines'])

babel = Babel(app)

import hashlib

import hmac

import re

import inspect

from io import StringIO

from codecs import getincrementalencoder

                         content, flags=re.I | re.U)

    return content

def is_flask_run_cmdline():

    """Check if the application was started using "flask run" command line

    Inspect the callstack.

    See https://github.com/pallets/flask/blob/master/src/flask/__main__.py

    Returns:

        bool: True if the application was started using "flask run".

    """

    frames = inspect.stack()

    if len(frames) < 2:

        return False

    return frames[-2].filename.endswith('flask/cli.py')