* MM-32893: Refactor the getting of DB handle
We add a method in *SqlStore that returns the correct DB handle
depending on the context.
https://mattermost.atlassian.net/browse/MM-32893
```release-note
NONE
```
* fix receiver name
* MM-30882: Fix read-after-write issue for demoting user
In (*App).DemoteUserToGuest, we would demote a user, and then immediately
read it back to do future operations from the user. This reading back
of the user had the effect of sticking the old value into the cache
after which it would never be updated.
There was another issue along with this, which was when the invalidation
message would broadcast across the cluster, it would hit the cache invalidation
problem where an unrelated store call would miss the cache because
it was invalidated, and then again read from replica and stick the old value.
To fix all these, we return the new value directly from the store method
to avoid having the app to read it again.
And we add a map in the localcache layer which tracks invalidations made,
and then switch to use master if it's true.
The core change is fairly limited, but due to changing the store method signatures,
a lot of code needed to be updated to pass "context.Background". Therefore the PR
just "appears" to be big, but the main changes are limited to app/user.go,
sqlstore/user_store.go and user_layer.go
https://mattermost.atlassian.net/browse/MM-30882
```release-note
Fix an issue where demoting a user to guest would not take effect in
an environment with read replicas.
```
* Fix concurrent map access
* Fixing mistakes
* fix tests
* format using `goimports -local github.com/mattermost/mattermost-server/v5 -w`
* added goimports lint check to .golangci.yml
* format using `goimports -local github.com/mattermost/mattermost-server/v5 -w` for a corner case
* make app-layers, *-mocks and store-layers for ci check
Co-authored-by: Mahmudul Haque <mahmudulhaque@protonmail.com>
Co-authored-by: Mattermod <mattermod@users.noreply.github.com>
* MM-30026: Use DB master when getting team members from a session
A race condition happens when the read-replica isn't updated yet
by the time a session expiry message reaches another node in the cluster.
Here is the sequence of events that can cause it:
- Server1 gets any request which has to wipe session cache.
- The SQL query is written to DB master, and a cluster message is propagated
to clear the session cache for that user.
- Now before the read-replica is updated with the master’s update,
the cluster message reaches Server2. The session cache is wiped out for that user.
- _Any random_ request for that user hits Server2. Does NOT have to be
the update team name request. The request does not find the value
in session cache, because it’s wiped off, and picks it up from the DB.
Surprise surprise, it gets the stale value. Sticks it into the cache.
By now, the read-replica is updated. But guess what, we aren’t going to
ask the DB anymore, because we have it in the cache. And the cache has the stale value.
We use a temporary approach for now by introducing a context in the DB calls so that
the useMaster information can be easily passed. And this has the added advantage of
reusing the same context for future DB calls in case it happens. And we can also
add more context keys as needed.
A proper approach needs some architectural changes. See the issue for more details.
```release-note
Fixed a bug where a session will hold on to a cached value
in an HA setup with read-replicas configured.
```
* incorporate review comments
Co-authored-by: Mattermod <mattermod@users.noreply.github.com>
