Streaming can not be used for these queries because the near query
paramter indicates a specific sort of the results, and that sort
requires data that is not available to the client from the streaming
API.
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.
Blocking queries issues will still be uncancellable (that cannot be helped until we get rid of net/rpc). However this makes it so that if calling getWithIndex (like during a cache Notify go routine) we can cancell the outer routine. Previously it would keep issuing more blocking queries until the result state actually changed.
In discussion with team, it was pointed out that query parameters tend
to be filter mechanism, and that semantically the "/v1/health/connect"
endpoint should return "all healthy connect-enabled endpoints (e.g.
could be side car proxies or native instances) for this service so I can
connect with mTLS".
That does not fit an ingress gateway, so we remove the query parameter
and add a new endpoint "/v1/health/ingress" that semantically means
"all the healthy ingress gateway instances that I can connect to
to access this connect-enabled service without mTLS"
This allows the operator to disable agent caching for the http endpoint.
It is on by default for backwards compatibility and if disabled will
ignore the url parameter `cached`.
* Use consts for well known tagged adress keys
* Add ipv4 and ipv6 tagged addresses for node lan and wan
* Add ipv4 and ipv6 tagged addresses for service lan and wan
* Use IPv4 and IPv6 address in DNS
* Support multiple tags for health and catalog api endpoints
Fixes#1781.
Adds a `ServiceTags` field to the ServiceSpecificRequest to support
multiple tags, updates the filter logic in the catalog store, and
propagates these change through to the health and catalog endpoints.
Note: Leaves `ServiceTag` in the struct, since it is being used as
part of the DNS lookup, which in turn uses the health check.
* Update the api package to support multiple tags
Includes additional tests.
* Update new tests to use the `require` library
* Update HealthConnect check after a bad merge
* Add cache types for catalog/services and health/services and basic test that caching works
* Support non-blocking cache types with Cache-Control semantics.
* Update API docs to include caching info for every endpoint.
* Comment updates per PR feedback.
* Add note on caching to the 10,000 foot view on the architecture page to make the new data path more clear.
* Document prepared query staleness quirk and force all background requests to AllowStale so we can spread service discovery load across servers.
- register endpoints with supported methods
- support OPTIONS requests, indicating supported methods
- extract method validation (error 405) from individual endpoints
- on 405 where multiple methods are allowed, create a single Allow
header with comma-separated values, not multiple Allow headers.
* agent: consolidate http method not allowed checks
This patch uses the error handling of the http handlers to handle HTTP
method not allowed errors across all available endpoints. It also adds a
test for testing whether the endpoints respond with the correct status
code.
* agent: do not panic on metrics tests
* agent: drop other tests for MethodNotAllowed
* agent: align /agent/join with reality
/agent/join uses PUT instead of GET as documented.
* agent: align /agent/check/{fail,warn,pass} with reality
/agent/check/{fail,warn,pass} uses PUT instead of GET as documented.
* fix some tests
* Drop more tests for method not allowed
* Align TestAgent_RegisterService_InvalidAddress with reality
* Changes API client join to use PUT instead of GET.
* Fixes agent endpoint verbs and removes obsolete tests.
* Updates the change log.
Daniel Nephin