Handle unavailable DB

[Liblor]

What happens when the db server becomes unavailable or returns an error for a query?
e.g. if a new certificate is issued and the transaction fails for some reason, does the application crash?

[Miro-H]

Maybe we should inform the webserver that the operation failed and it should retry?
Also at the moment the connection to a single DB is hardcoded in the connection string. To really use both DBs, we either need to do load balancing with DNS resolution or find a ASP.NET internal solution.

I have to test what happens right now, my guess is

• If the initial connection to the DB fails, an internal error on the CA is thrown
• When the transaction fails, it will be retried (forever?)
• A normal query may fail silently...

[keyctl]

Maybe we should inform the webserver that the operation failed and it should retry?

We should probably have some indication if a request was successful or not generally. That way the WebServer can easily check if everything went as supposed.

Also at the moment the connection to a single DB is hardcoded in the connection string. To really use both DBs, we either need to do load balancing with DNS resolution or find a ASP.NET internal solution.

Load balancing might not even help here, not sure. This depends on whether or not ASP.NET resolves the IP on each new request (which I doubt, some connection should stay open for efficiency), or if it retries to resolve on errors. If neither is the case, then we would have to reconnect manually.

[Miro-H]

We should probably have some indication if a request was successful or not generally. That way the WebServer can easily check if everything went as supposed.

Generally, I do use HTTP response codes. 200 if everything went well, 401 if authentication failed (wrong username/password) and 400 if the request was malformed. They should be documented in the swagger GUI as well.
The problem with the DB is that this fails behind the scenes, so it's currently not part of my control flow.

Load balancing might not even help here, not sure. This depends on whether or not ASP.NET resolves the IP on each new request (which I doubt, some connection should stay open for efficiency), or if it retries to resolve on errors. If neither is the case, then we would have to reconnect manually.

Yes, or it is smart enough to try resolving the hostname again if the current IP is unreachable. I'll look into this, most likely we're not the first with that problem, so I hope there is a good solution for it.