Unable to render template with flask wsgi [duplicate] - python-3.x

Question

This question already has answers here:
Flask raises TemplateNotFound error even though template file exists
(13 answers)
Closed 2 years ago.
I have deployed a flask application, using mod_wsgi with apache2
Now, checking if everything works as intended, it looks like my endpoints which render templates are provoking some 500 status code errors.
Here's an approximative tree of my project:
main_folder
requirements.txt
mainfile.wsgi
app_folder
controllers
views.py
models
repository
services
static
templates
terms
en
terms.html
fr
terms.html
uploads
__init__.py
config.cfg
webapp.py
I am calling an endpoint which is supposed to render the templates/terms/en/terms.html and I get the following in the logs:
Traceback (most recent call last):
File "/usr/local/lib/python3.7/dist-packages/flask/app.py", line 2446, in wsgi_app
response = self.full_dispatch_request()
File "/usr/local/lib/python3.7/dist-packages/flask/app.py", line 1951, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/usr/local/lib/python3.7/dist-packages/flask/app.py", line 1820, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/usr/local/lib/python3.7/dist-packages/flask/_compat.py", line 39, in reraise
raise value
File "/usr/local/lib/python3.7/dist-packages/flask/app.py", line 1949, in full_dispatch_request
rv = self.dispatch_request()
File "/usr/local/lib/python3.7/dist-packages/flask/app.py", line 1935, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/var/www/main_folder/app_folder/controllers/views.py", line 33, in gts
return render_template('terms/' + lang + '/terms.html')
File "/usr/local/lib/python3.7/dist-packages/flask/templating.py", line 138, in render_template
ctx.app.jinja_env.get_or_select_template(template_name_or_list),
File "/usr/local/lib/python3.7/dist-packages/jinja2/environment.py", line 869, in get_or_select_template
return self.get_template(template_name_or_list, parent, globals)
File "/usr/local/lib/python3.7/dist-packages/jinja2/environment.py", line 830, in get_template
return self._load_template(name, self.make_globals(globals))
File "/usr/local/lib/python3.7/dist-packages/jinja2/environment.py", line 804, in _load_template
template = self.loader.load(self, name, globals)
File "/usr/local/lib/python3.7/dist-packages/jinja2/loaders.py", line 113, in load
source, filename, uptodate = self.get_source(environment, name)
File "/usr/local/lib/python3.7/dist-packages/flask/templating.py", line 60, in get_source
return self._get_source_fast(environment, template)
File "/usr/local/lib/python3.7/dist-packages/flask/templating.py", line 89, in _get_source_fast
raise TemplateNotFound(template)
jinja2.exceptions.TemplateNotFound: terms/en/terms.html
Here's an excerp of the code where I try to render the template in app_folder/controllers/views.py:
from flask import render_template, request, send_file
from app_folder.controllers import Controllers as controllers
def gts(lang='fr'):
return render_template('terms/' + lang + '/terms.html')
controllers().register(
'/cgu/<string:lang>',
'cgu_lang',
gts
)
I want to specify that endpoints with JSON body results are functionning, uploading ressources are working as well, and getting an uploaded ressource is working.
Only endpoints which should render templates are not working, which is getting me worried as well for endpoints which should send emails using an email template
Is there any fix I should apply when serving the application with wsgi?
Edit: FYI, this is the __init__.py in the controllers folder
import pkgutil
METHODS = set([
'GET',
'POST',
'PUT',
'PATCH',
'DELETE',
'COPY',
'HEAD',
'OPTIONS',
'LINK',
'UNLINK',
'PURGE',
'LOCK',
'UNLOCK',
'PROPFIND',
'VIEW'
])
class Controllers:
class __OnlyOne:
# ======================================================
# the code goes here
# =======================================================
def __init__(self):
self.val = None
self.rules = []
def __str__(self):
return 'self' + self.val
def register(self, rule, view_name, view_func):
r = {}
r["rule"] = rule
r["view_name"] = view_name
r["view_func"] = view_func
self.rules.append(r)
def register_methods(self, rule, view_name, view_func, methods=METHODS):
r = {}
r["rule"] = rule
r["view_name"] = view_name
r["view_func"] = view_func
r["methods"] = methods
self.rules.append(r)
def grab(self, app):
for r in self.rules:
if "methods" not in r.keys():
app.add_url_rule(r["rule"], r["view_name"], r["view_func"])
else:
app.add_url_rule(r["rule"], r["view_name"],
r["view_func"], methods=r["methods"])
# =================================================================
# the code goes up there
# ==================================================================
instance = None
def __new__(cls): # __new__ always a classmethod
if not Controllers.instance:
Controllers.instance = Controllers.__OnlyOne()
return Controllers.instance
def __getattr__(self, name):
return getattr(self.instance, name)
def __setattr__(self, name):
return setattr(self.instance, name)
# import all the modules in folder
__all__ = []
for loader, module_name, is_pkg in pkgutil.walk_packages(__path__):
__all__.append(module_name)
_module = loader.find_module(module_name).load_module(module_name)
globals()[module_name] = _module

Answer 1

I symlinked my app_folder/templates into my main_folder and it's now working