Better 500 template (show exception, point to logs)

bugsink/urls.py

@@ -63,3 +63,6 @@ if settings.DEBUG:
         path('trigger-error/', trigger_error),
         path("__debug__/", include("debug_toolbar.urls")),
     ]
+
+
+handler500 = "bugsink.views.server_error"

bugsink/views.py

@@ -1,3 +1,9 @@
+import sys
+
+from django.http import HttpResponseServerError
+from django.template import TemplateDoesNotExist, loader
+from django.views.decorators.csrf import requires_csrf_token
+from django.views.defaults import ERROR_500_TEMPLATE_NAME, ERROR_PAGE_TEMPLATE
 from django.shortcuts import redirect
 from django.conf import settings
 
@@ -108,3 +114,22 @@ def settings_view(request):
         "misc_settings": misc_settings,
         "version": __version__,
     })
+
+
+@requires_csrf_token
+def server_error(request, template_name=ERROR_500_TEMPLATE_NAME):
+    # verbatim copy of Django's default server_error view, but with "exception" in the context
+    # doing this for any-old-Django-site is probably a bad idea, but here the security/convenience tradeoff is fine,
+    # especially because we only show str(exception) in the template.
+    try:
+        template = loader.get_template(template_name)
+    except TemplateDoesNotExist:
+        if template_name != ERROR_500_TEMPLATE_NAME:
+            # Reraise if it's a missing custom template.
+            raise
+        return HttpResponseServerError(
+            ERROR_PAGE_TEMPLATE % {"title": "Server Error (500)", "details": ""},
+        )
+
+    _, exception, _ = sys.exc_info()
+    return HttpResponseServerError(template.render({"exception": exception}, request))

templates/500.html

@@ -6,7 +6,16 @@
 <div class="m-4">
 <h1 class="text-4xl mt-4 font-bold">500 Server Error</h1>
 
-<div class="pt-2">
-    There was an internal server error.
+<div class="pt-2 font-bold">
+    {{ exception }}
 </div>
+
+<div class="pt-6">
+    You will find more information in:
+    <ul class="list-disc pt-4 pl-4">
+        <li>the server logs (stdout of your Docker, or in journalctl)</li>
+        <li>if you're <a href="https://www.bugsink.com/docs/dogfooding/" class="text-cyan-500 font-bold">dogfooding Bugsink</a>, in Bugsink itself</li>
+    </ul>
+</div>
+
 {% endblock %}