* agent: remove agent cache dependency from service mesh leaf certificate management
This extracts the leaf cert management from within the agent cache.
This code was produced by the following process:
1. All tests in agent/cache, agent/cache-types, agent/auto-config,
agent/consul/servercert were run at each stage.
- The tests in agent matching .*Leaf were run at each stage.
- The tests in agent/leafcert were run at each stage after they
existed.
2. The former leaf cert Fetch implementation was extracted into a new
package behind a "fake RPC" endpoint to make it look almost like all
other cache type internals.
3. The old cache type was shimmed to use the fake RPC endpoint and
generally cleaned up.
4. I selectively duplicated all of Get/Notify/NotifyCallback/Prepopulate
from the agent/cache.Cache implementation over into the new package.
This was renamed as leafcert.Manager.
- Code that was irrelevant to the leaf cert type was deleted
(inlining blocking=true, refresh=false)
5. Everything that used the leaf cert cache type (including proxycfg
stuff) was shifted to use the leafcert.Manager instead.
6. agent/cache-types tests were moved and gently replumbed to execute
as-is against a leafcert.Manager.
7. Inspired by some of the locking changes from derek's branch I split
the fat lock into N+1 locks.
8. The waiter chan struct{} was eventually replaced with a
singleflight.Group around cache updates, which was likely the biggest
net structural change.
9. The awkward two layers or logic produced as a byproduct of marrying
the agent cache management code with the leaf cert type code was
slowly coalesced and flattened to remove confusion.
10. The .*Leaf tests from the agent package were copied and made to work
directly against a leafcert.Manager to increase direct coverage.
I have done a best effort attempt to port the previous leaf-cert cache
type's tests over in spirit, as well as to take the e2e-ish tests in the
agent package with Leaf in the test name and copy those into the
agent/leafcert package to get more direct coverage, rather than coverage
tangled up in the agent logic.
There is no net-new test coverage, just coverage that was pushed around
from elsewhere.
Replace two methods with a single one that returns the cert. This moves more
of the logic into the single caller (auto-config).
tlsutil.Configurator is widely used. By keeping it smaller and focused only on storing and
returning TLS config, we make the code easier to follow.
These two methods were more related to auto-config than to tlsutil, so reducing the interface
moves the logic closer to the feature that requires it.
This commit reduces the interface to Load() a bit, in preparation for
unexporting NewBuilder and having everything call Load.
The three arguments are reduced to a single argument by moving the other
two into the options struct.
The three return values are reduced to two by moving the RuntimeConfig
and Warnings into a LoadResult struct.
Reduce Jitter to one function
Rename NewRetryWaiter
Fix a bug in calculateWait where maxWait was applied before jitter, which would make it
possible to wait longer than maxWait.
This is a small step to allowing Agent to accept its dependencies
instead of creating them in New.
There were two fields in autoconfig.Config that were used exclusively
to load config. These were replaced with a single function, allowing us
to move LoadConfig back to the config package.
Also removed the WithX functions for building a Config. Since these were
simple assignment, it appeared we were not getting much value from them.
Most of the groundwork was laid in previous PRs between adding the cert-monitor package to extracting the logic of signing certificates out of the connect_ca_endpoint.go code and into a method on the server.
This also refactors the auto-config package a bit to split things out into multiple files.
R.B. Boyer