Proxy tasks emit events to the telemetry system. These events are used
aggregate counts and latencies, as well as to inform Tap requests.
Initially, these events included durations, describing the relevant time
that elapsed between this event and another.
This approach is somewhat inflexible -- it unnecessarily constrains the
set of measurements that can computed in the telemetry system.
To remedy this, the `Event` types can be changed to report discrete
`Instant`s (rather than `Duration`s). Then, when latencies are computed
in the telemetry system, these discrete instants can be compared to
produce durations.
There are no functional changes in this PR.
Now, the tap server may specify that requests should be matched by destination
label.
For example, if the controller's Destination service returns the labels:
`{"service": "users", "namespace": "prod"}` for an endpoint, then tap would be
able to specify a match like `namespace=prod` to match requests destined to
that namespace.
Currently, the mock controller, which is used in tests, takes all of its
updates a priori, which makes it hard to control when an update occurs within a
test.
Now, the controller exposes a `DstSender`, which wraps an unbounded channel of
destination updates. This allows tests to trigger updates at a specific point
in the test.
In order to accomplish this, the controller's hand-rolled gRPC server
implementation has been discarded in favor of a real gRPC destination service.
This requires that the `controller-grpc` project now builds both clients
and servers for the destination service. Additionally, we now build a tap
client as well (assuming that we'll want to write tests against our tap
server).
Turning off the default features of quickcheck removes its
`env_logger` and `log` dependencies. It uses older versions of
those packages than conduit-proxy will use, so this will
(eventually) reduce the number of versions of those packages that
get downloaded and built.
Signed-off-by: Brian Smith <brian@briansmith.org>
The proxy depends on `protoc`-generated gRPC bindings to communicate
with the controller. In order to generate these bindings, build-time
dependencies must be compiled.
In order to support a more granular, cacheable build scheme, a new crate
has been created to house these gRPC bindings,
`conduit-proxy-controller-grpc`.
Because `TryFrom` and `TryInto` conversions are implemented for
protobuf-defined types, the `convert` module also had to be moved to
into a dedicated crate.
Furthermore, because the proxy's tests require that
`quickcheck::Aribtrary` be implemented for protobuf types, the
`conduit-proxy-controller-grpc` crate supports an _arbitrary_ feature
fla protobuf types, the `conduit-proxy-controller-grpc` crate supports
an _arbitrary_ feature flag.
While we're moving these libraries around, the `tower-router` crate has
been moved to `proxy/router` and renamed to `conduit-proxy-router.`
`futures-mpsc-lossy` has been moved into the proxy directory but has not
been renamed.
Finally, the `proxy/Dockerfile-deps` image has been updated to avoid the
wasteful building of dependency artifacts, as they are not actually used
by `proxy/Dockerfile`.