fix(views): skip checks if value isn't iterable

[alpden550]

Fix TypeError at /watchman/dashboard/

for dashboard view, when Redis or something else is down

[mwarkentin]

@alpden550 thanks for the PR, just wanted to let you know that I'm on vacation through august so won't have a chance to merge / release this for a while.

[alpden550]

@mwarkentin ok, thank you!

[mwarkentin]

@alpden550 really sorry about not getting back to this after I came back online - I'm working on pulling some things together for a new releases and was wondering if you're still interested in getting this change in? It would be helpful if you'd be available to test a preview release or answer any questions I run into. Let me know! :)

[alpden550]

@mwarkentin
Hello, what exactly do you mean about answering any questions ?

[mwarkentin]

@alpden550 just in case I have some trouble trying to reproduce / test the fix, etc.

[alpden550]

@mwarkentin of course
I've caught it when not Redis or celery exists and instance was not iterable

[mwarkentin]

@alpden550 I'm trying to reproduce the issue on main so that I can test this fix..

I'm testing on the sample project which can be run in docker using make run.

I added a Redis cache backend, but am not running Redis:

❯ g diff
diff --git a/sample_project/requirements.txt b/sample_project/requirements.txt
index c60fab3..c7472e0 100644
--- a/sample_project/requirements.txt
+++ b/sample_project/requirements.txt
@@ -1,4 +1,5 @@
 django<5.0,>=4.0
+redis==4.1.0

 # django-watchman
 -e /app
diff --git a/sample_project/sample_project/settings.py b/sample_project/sample_project/settings.py
index b4438d6..e257a4c 100644
--- a/sample_project/sample_project/settings.py
+++ b/sample_project/sample_project/settings.py
@@ -108,6 +108,13 @@ AUTH_PASSWORD_VALIDATORS = [
     },
 ]

+CACHES = {
+    'default': {
+        'BACKEND': 'django.core.cache.backends.redis.RedisCache',
+        'LOCATION': 'redis://127.0.0.1:6379',
+    }
+}
+

When I hit the dashboard I see:

And the traceback:

Traceback (most recent call last):
  File "/usr/local/lib/python3.10/site-packages/redis/connection.py", line 607, in connect
    sock = self._connect()
  File "/usr/local/lib/python3.10/site-packages/redis/connection.py", line 671, in _connect
    raise err
  File "/usr/local/lib/python3.10/site-packages/redis/connection.py", line 659, in _connect
    sock.connect(socket_address)
ConnectionRefusedError: [Errno 111] Connection refused

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/app/watchman/decorators.py", line 29, in wrapped
    response = func(*args, **kwargs)
  File "/app/watchman/checks.py", line 29, in _check_cache
    cache.set(key, value)
  File "/usr/local/lib/python3.10/site-packages/django/core/cache/backends/redis.py", line 191, in set
    self._cache.set(key, value, self.get_backend_timeout(timeout))
  File "/usr/local/lib/python3.10/site-packages/django/core/cache/backends/redis.py", line 108, in set
    client.set(key, value, ex=timeout)
  File "/usr/local/lib/python3.10/site-packages/redis/commands/core.py", line 1691, in set
    return self.execute_command("SET", *pieces, **options)
  File "/usr/local/lib/python3.10/site-packages/redis/client.py", line 1170, in execute_command
    conn = self.connection or pool.get_connection(command_name, **options)
  File "/usr/local/lib/python3.10/site-packages/redis/connection.py", line 1311, in get_connection
    connection.connect()
  File "/usr/local/lib/python3.10/site-packages/redis/connection.py", line 611, in connect
    raise ConnectionError(self._error_message(e))
redis.exceptions.ConnectionError: Error 111 connecting to 127.0.0.1:6379. Connection refused.

Any chance you could provide an example config which can help me reproduce this issue?

[alpden550]

@mwarkentin yes, I got it and reproduce for you.

I use docker-compose containers, and if all services work, all fine. Example:

My services like that, nothing specials

version: '3.9'

services:
  app:
    build: .
    command: python manage.py runserver 0.0.0.0:8000
    volumes:
      - .:/app
    ports:
      - "8000:8000"
    env_file:
      - url_shortener/.env.dev
    depends_on:
      - db
      - redis

  db:
    image: postgres
    env_file:
      - url_shortener/.env.dev

  redis:
    image: redis

  celery:
    build: .
    volumes:
      - .:/app
    depends_on:
      - redis
      - db
    env_file:
      - url_shortener/.env.dev
    command: celery -A url_shortener worker -l info

  email:
    build: .
    volumes:
      - .:/app
    depends_on:
      - redis
      - db
    env_file:
      - url_shortener/.env.dev
    command: celery -A url_shortener worker -l info

  tgbot:
    build: .
    env_file:
      - url_shortener/.env.dev
    depends_on:
      - app
    links:
      - app
    command: sh -c "python manage.py startbot"

But if Redis was stopped, this error happens

[mwarkentin]

Thanks, I'll give it another try to reproduce with what you've provided.