Add event cancellation

[spreeni]

closes #4178

• Backend: Added RPC for event cancellation and deletion
• Backend: Adjusted Event DB schema
• Backend: Deny selected actions on cancelled event
• Backend: Deleted events should never show up
• Backend: Notify attendants if an event got cancelled/deleted
• Frontend: Add button to cancel event
• Frontend: Display cancelled events accordingly
  • Grey cancelled events out in overview
  • Make all buttons disabled for cancelled events
  • Add red chip for cancelled events

Backend checklist

• Formatted my code by running autoflake --exclude src/proto -r -i --remove-all-unused-imports src && isort . && black . in app/backend
• Added tests for any new code or added a regression test if fixing a bug
• All tests pass
• Run the backend locally and it works
• Added migrations if there are any database changes, rebased onto develop if necessary for linear migration history

Web frontend checklist

• Formatted my code with make format
• There are no warnings from make lint
• There are no console warnings when running the app
• Added any new components to storybook
• Added tests where relevant
• All tests pass
• Clicked around my changes running locally and it works
• Checked Desktop, Mobile and Tablet screen sizes

[aapeliv]

Let me know if you need anything for this.

[spreeni]

@aapeliv @jesseallhands How do we want to display cancelled events? In my idea, they should later not show up in event searches at all, but should still show up under a tab "My Events" or so, if you joined one previously.

In the current version, as we don't have too many events yet, I guess we display cancelled events as well, but should make it visually clear that they are/were cancelled. How should we do that best? (I am slightly limited by my frontend dev skills here) My idea for now was to grey them out a bit and include a "cancelled" badge.

[jesseallhands]

@aapeliv @jesseallhands How do we want to display cancelled events? In my idea, they should later not show up in event searches at all, but should still show up under a tab "My Events" or so, if you joined one previously.

In the current version, as we don't have too many events yet, I guess we display cancelled events as well, but should make it visually clear that they are/were cancelled. How should we do that best? (I am slightly limited by my frontend dev skills here) My idea for now was to grey them out a bit and include a "cancelled" badge.

Yes, I think cancelled events should be under a separate cancelled events tab and the event itself should use a bright "cancelled!" pill (badge) to mark it, so if someone has the link to the event and they go to it, they easily see it has been cancelled.

As far as deleted events go, those shouldn't be shown on the website at all, but should still be queryable on the backend.

[spreeni]

So I chose to include a switch for now to display cancelled events. I think soon, as discussed, we could have a new events page layout (see #3989).

Cancelled events are greyed out and highlighted with a "cancelled" chip. On the page of a cancelled event the buttons are disabled and greyed out.

Deleted events can't be queried at all through the API, but are still available in the database. I thought it might be better to avoid accidentally displaying a deleted event. But an alternative could be that only superusers can query deleted events.

[spreeni]

There are 4 different places where events are currently listed, this is how I chose to deal with cancelled events for each of these:

• Dashboard: Cancelled events are not shown (Here ListMyEvents is called, where a include_cancelled flag could be used to include these though)
• Events page: Cancelled events are by default not shown, but can be toggled to be shown
• Community page overview: Cancelled events are not shown
• Community page events tab: Cancelled events are not shown

I think viewing cancelled events does only make sense if wondering why an event I joined previously was cancelled or to look for other attendees/information and is therefore quite conscious.

[aapeliv]

There are 4 different places where events are currently listed, this is how I chose to deal with cancelled events for each of these:

• Dashboard: Cancelled events are not shown (Here ListMyEvents is called, where a include_cancelled flag could be used to include these though)

• Events page: Cancelled events are by default not shown, but can be toggled to be shown

• Community page overview: Cancelled events are not shown

• Community page events tab: Cancelled events are not shown

I think viewing cancelled events does only make sense if wondering why an event I joined previously was cancelled or to look for other attendees/information and is therefore quite conscious.

I think this is great!

[aapeliv]

It looks mostly good on the backend, a few small comments. I will have another look when I'm back on my computer!

[aapeliv]

What does this one do?

[spreeni]

Altering a type has to be run outside of a transaction, which this context manager allows, if I understood that correctly. Read this in Stackoverflow and on alembic docs.

Howevery, I saw that you did it in a previous migration without it, so maybe it is not necessary...

[aapeliv]

Could you please combine the two migrations into one file. And please rebase on develop (you might need to change the down revision to the latest value) to keep a linear alembic history.

[spreeni]

I combined the migrations now - I merged develop into this branch already and added these migrations on top, so the history is linear.