This adds a new very tiny memdb table and corresponding raft operation
for updating a very small effective map[string]string collection of
"system metadata". This can persistently record a fact about the Consul
state machine itself.
The first use of this feature will come in a later PR.
* Create Topology Tab with foundational layout and styling
* Create Toplogy Metrics component with dynamic SVG
* Add ember-render-modifiers addon
* Implement Topology Metrics comp and fix up styling
* Create topology endpoint with tests
* Move arrow drawing to index.js file
* Add topology to show controller
* Fix up conditional wrapper, tabs positioning, links, and styling
* Group upstreams by dc and fix up styling
* Create service/health-percentage helper
* Add health check percentages to upstreams and downstreams
* Basic Layout
* Upgrade @hashicorp/consul-api-double to v5.2.3
* Renamed endpoint to be service-topology
* Refactor styling
* Update to only show Topology tab when Connect is enabled
* Fix bug and changes from review notes
* Remove unused functions that are replaced with SVG markers
* Refactor to resuse svg-curve helper
* Use the render-template helper for the metrics link
* Add topology default null to services show route
* Removed unused ID
* Fix up tests broken by redirect to /topology
This new package provides a client agent implementation of an interface
for fetching the health of services.
This approach has a number of benefits:
1. It provides a much more explicit interface. Instead of everything
dependency on `RPC()` and `Cache.Get()` for many unrelated things
they can depend on a type that are named according to the behaviour
it provides.
2. It gives us a single place to vary the behaviour and migrate to
a new form of RPC (gRPC). The current implementation has two options
(cache, or direct RPC), and in the future we will have more.
It is also a great opporunity to start adding `context.Context` args
to these operations, which in the future will allow us to cancel
the operations.
3. As a concequence of the first, in the Server agent where we make
these calls we can replace the current in-memory RPC calls with
a thin adapter for the real method. This removes the `net/rpc`
machinery from the call in places where it is not needed.
This new package is quite small right now, but I think we can expect it
to grow to a more reasonable size as other RPC calls are replaced.
This change also happens to replace two very similar implementations with
a single implementation.