Coverts getting values in the `FnCache` from `FnCache.Get` to
`utils.FnCacheGet[T any]`. This allows us to have compile time
guarantees for the type being loaded, which allows us to remove
some of the manual type checking required of callers today.
Adds a `trace.Tracer` to the `cache.Cache`so
that all operations can be traced. Also, updates
the `utils.FnCache` to link the `context.Context`
passed to the loadFn to any current spans. This
will allow any fetches made by the `FnCache` to
be associated with the call that lead to loading.
Note: There are a few methods in the `auth.Cache`
interface which do not take a `context.Context`.
For the time being all spans for these calls use
a `context.TODO` and will be updated in the future,
where the changes can be made on a per method basis.
* FnCache context improvements
Modifies the FnCache to be constructed with a context.Context
which is passed to all loadfn provided to Get. This removes
the burden placed on callers to ensure loadfn are not request
context scoped.
* Dynamically resolve reverse tunnel address
The reverse tunnel address is currently a static string that is
retrieved from config and passed around for the duration of a
services lifetime. When the `tunnel_public_address` is changed
on the proxy and the proxy is then restarted, all established
reverse tunnels over the old address will fail indefinintely.
As a means to get around this, #8102 introduced a mechanism
that would cause nodes to restart if their connection to the
auth server was down for a period of time. While this did
allow the nodes to pickup the new address after the nodes
restarted it was meant to be a stop gap until a more robust
solution could be applid.
Instead of using a static address, the reverse tunnel address
is now resolved via a `reversetunnel.Resolver`. Anywhere that
previoulsy relied on the static proxy address now will fetch
the actual reverse tunnel address via the webclient by using
the Resolver. In addition this builds on the refactoring done
in #4290 to further simplify the reversetunnel package. Since
we no longer track multiple proxies, all the left over bits
that did so have been removed to accomodate using a dynamic
reverse tunnel address.
Forrest Marshall