This is the OSS portion of enterprise PR 2141.
This commit provides a server-local implementation of the `proxycfg.Intentions`
interface that sources data from streaming events.
It adds events for the `service-intentions` config entry type, and then consumes
event streams (via materialized views) for the service's explicit intentions and
any applicable wildcard intentions, merging them into a single list of intentions.
An alternative approach I considered was to consume _all_ intention events (via
`SubjectWildcard`) and filter out the irrelevant ones. This would admittedly
remove some complexity in the `agent/proxycfg-glue` package but at the expense
of considerable overhead from waking potentially many thousands of connect
proxies every time any intention is updated.
OSS portion of enterprise PR 1857.
This removes (most) references to the `cache.UpdateEvent` type in the
`proxycfg` package.
As we're going to be direct usage of the agent cache with interfaces that
can be satisfied by alternative server-local datasources, it doesn't make
sense to depend on this type everywhere anymore (particularly on the
`state.ch` channel).
We also plan to extract `proxycfg` out of Consul into a shared library in
the future, which would require removing this dependency.
Aside from a fairly rote find-and-replace, the main change is that the
`cache.Cache` and `health.Client` types now accept a callback function
parameter, rather than a `chan<- cache.UpdateEvents`. This allows us to
do the type conversion without running another goroutine.
Prior to this PR for the envoy xDS golden tests in the agent/xds package we
were hand-creating a proxycfg.ConfigSnapshot structure in the proper format for
input to the xDS generator. Over time this intermediate structure has gotten
trickier to build correctly for the various tests.
This PR proposes to switch to using the existing mechanism for turning a
structs.NodeService and a sequence of cache.UpdateEvent copies into a
proxycfg.ConfigSnapshot, as that is less error prone to construct and aligns
more with how the data arrives.
NOTE: almost all of this is in test-related code. I tried super hard to craft
correct event inputs to get the golden files to be the same, or similar enough
after construction to feel ok that i recreated the spirit of the original test
cases.
Kyle Havlovitz