Test django-cachalot

The following discussion from AlekSIS-App-Alsijil!90 (merged) should be addressed:

• @nik started a discussion: (+1 comment)

  We might want https://github.com/noripyt/django-cachalot

moved from AlekSIS-App-Alsijil#116 (moved)

created merge request !379 (merged) to address this issue

mentioned in merge request !379 (merged)

assigned to @hansegucker

changed the description

Currently, I have to restart memcached if I did a restart of uWSGI. Is this behavior correct?

Maybe, maybe not. What's more interesting is why you conclude you have to restart it, or what happens if you don't.

If I don't do a restart, there will be KeyErrors according to cache keys in Django.

Maybe you can paste one of those, including a stacktrace………

Traceback (most recent call last):
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/core/handlers/wsgi.py", line 133, in __call__
    response = self.get_response(request)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/core/handlers/base.py", line 128, in get_response
    response = self._middleware_chain(request)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/core/handlers/exception.py", line 49, in inner
    response = response_for_exception(request, exc)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/core/handlers/exception.py", line 103, in response_for_exception
    response = handle_uncaught_exception(request, get_resolver(get_urlconf()), sys.exc_info())
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/core/handlers/exception.py", line 142, in handle_uncaught_exception
    return callback(request, **param_dict)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/utils/decorators.py", line 130, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/views/defaults.py", line 97, in server_error
    return HttpResponseServerError(template.render())
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/template/backends/django.py", line 61, in render
    return self.template.render(context)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/template/base.py", line 170, in render
    return self._render(context)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/test/utils.py", line 96, in instrumented_test_render
    return self.nodelist.render(context)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/template/loader_tags.py", line 150, in render
    return compiled_parent._render(context)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/test/utils.py", line 96, in instrumented_test_render
    return self.nodelist.render(context)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/template/loader_tags.py", line 192, in render
    return template.render(context)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/template/base.py", line 172, in render
    return self._render(context)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/test/utils.py", line 96, in instrumented_test_render
    return self.nodelist.render(context)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/template/base.py", line 938, in render
    bit = node.render_annotated(context)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/template/base.py", line 905, in render_annotated
    return self.render(context)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/template/library.py", line 192, in render
    output = self.func(*resolved_args, **resolved_kwargs)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/favicon/templatetags/favtags.py", line 25, in place_favicon
    n = fav.get_favicon(size=size, rel=rel)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/favicon/models.py", line 79, in get_favicon
    faviconFK=self, size=size, rel=rel)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/db/models/query.py", line 573, in get_or_create
    return self.get(**kwargs), False
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/db/models/query.py", line 425, in get
    num = len(clone)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/db/models/query.py", line 269, in __len__
    self._fetch_all()
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/db/models/query.py", line 1308, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/db/models/query.py", line 53, in __iter__
    results = compiler.execute_sql(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/cachalot/monkey_patch.py", line 29, in inner
    return original(compiler, *args, **kwargs)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/cachalot/monkey_patch.py", line 87, in inner
    cache_key, table_cache_keys)
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/cachalot/monkey_patch.py", line 37, in _get_result_or_execute_query
    data = cache.get_many(table_cache_keys + [cache_key])
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/django/core/cache/backends/memcached.py", line 93, in get_many
    ret = self._cache.get_multi(key_map.keys())
  File "/srv/venvs/aleksis-9fsiETir-py3.7/lib/python3.7/site-packages/memcache.py", line 1216, in get_multi
    retvals[prefixed_to_orig_key[rkey]] = val
KeyError: b':1:af167bf678e72a9b2a64d8869d420b8d25e96148'

closed with merge request !379 (merged)

mentioned in commit 15008433