### Description
Fix https://github.com/grpc/grpc/issues/24470.
Adding one example which demonstrate the following use cases:
* Generate RPC ID on client side and propagate to server.
* Context propagation from client to server.
* Context propagation between different server interceptors and the
server handler.
## Use:
1. Start server: `python3 -m async_greeter_server_with_interceptor`
2. Start client: `python3 -m async_greeter_client`
### Expected Logs:
* On client side:
```
Sending request with rpc id: 73bb98beff10c2dd7b9f2252a1e2039e
Greeter client received: Hello, you!
```
* On server side:
```
INFO:root:Starting server on [::]:50051
INFO:root:Interceptor1 called with rpc_id: default
INFO:root:Interceptor2 called with rpc_id: Interceptor1-default
INFO:root:Handle rpc with id Interceptor2-Interceptor1-73bb98beff10c2dd7b9f2252a1e2039e in server handler.
```
Oops I missed important changes from
https://github.com/grpc/grpc/pull/32712. And it turned out that there
are two problems that I couldn't fix at this point.
- Windows Bazel RBE Linker Error: This may be caused by how new Bazel 6
invokes build tools chain but it's not clear. I put workaround to use
Bazel 5 by using `OVERRIDE_BAZEL_VERSION=5.4.1`
- Rule `rules_pods` to fetch CronetFramework from CocoaPod has
incompatibility with sort of built-in apple toolchain.
(https://github.com/bazel-xcode/PodToBUILD/issues/232): I couldn't find
a workaround to fix this so I ended up disabling all tests depending
this target.
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I'm opening this PR to (hopefully!) stimulate a discussion. In brief,
I'd like to amend the gRPC-Web protocol docs to encourage
implementations to follow HTTP semantics and compare HTTP field names
case-insensitively.
The gRPC-Web specification is a nicely-designed way for proxies to
expose standard HTTP/2 gRPC servers to clients using less
tightly-controlled HTTP stacks, such as web browsers. To serve that
goal, it seems valuable to have the gRPC-Web specification follow [RFC
9110 (HTTP
Semantics)](https://www.rfc-editor.org/rfc/rfc9110.html#name-field-names).
Like previous RFCs, 9110 specifies that "field names are
case-insensitive." However, the current gRPC-Web specification requires
that servers and proxies "use lower-case header/trailer names" on the
wire. In principle, mandating casing on the wire is normal for HTTP/2
and fine (if unusual) for HTTP/1.1; however, it encourages
implementations to violate HTTP semantics and require lower-case names
when _reading_ headers and trailers.
I'd like to loosen the gRPC-Web specification to permit any casing on
the wire for HTTP/1.1. I'd also like to emphasize that gRPC-Web
implementations ought to follow standard HTTP semantics when _reading_
fields and compare names case-insensitively. Implementations that can't
treat names case-insensitively without breaking backward compatibility
should instead normalize field names to lowercase. Among the
Google-maintained gRPC implementations, at least `grpc-go` and
`grpc-java` already compare names case-insensitively (even though
they're HTTP/2-only). `grpc-dart` does the opposite and compares names
case-sensitively. `grpc-web` is sometimes case-insensitive (when reading
`grpc-status` and `grpc-message` from trailers-only responses) and
sometimes case-sensitive (when hand-parsing a block of length-prefixed
trailers).
The proposed amendment does not affect the correctness of Envoy (which
may continue to use lower-case field names). It partially affects
`grpc-web`, which would require a small patch to always normalize names.
(Both patched and unpatched versions of `grpc-web` would work with
Envoy.) `grpc-dart` would need to either begin treating field names
case-insensitively or normalize names, depending on what's possible in
Dart without breaking backward compatibility.
Relates to https://github.com/improbable-eng/grpc-web/issues/228,
https://github.com/bufbuild/connect-go/issues/453/, and
https://github.com/grpc/grpc-dart/issues/594.
cc @markdroth
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* WRR: port StaticStrideScheduler to OSS
* WIP
* Automated change: Fix sanity tests
* fix build
* remove unused aliases
* fix another type mismatch
* remove unnecessary include
* move benchmarks to their own file, and don't run it on windows
* Automated change: Fix sanity tests
* add OOB reporting
* generate_projects
* clang-format
* add config parser test
* clang-tidy and minimize lock contention
* add config defaults
* add oob_reporting_period config field and add basic test
* Automated change: Fix sanity tests
* fix test
* change test to use basic RR
* WIP: started exposing peer address to LB policy API
* first WRR test passing!
* small cleanup
* port RR fix to WRR
* test helper refactoring
* more test helper refactoring
* WIP: trying to fix test to have the right weights
* more WIP -- need to make pickers DualRefCounted
* fix timer ref handling and get tests working
* clang-format
* iwyu and generate_projects
* fix build
* add test for OOB reporting
* keep only READY subchannels in the picker
* add file missed in a previous commit
* fix sanity
* iwyu
* add weight expiration period
* add tests for weight update period and OOB reporting period
* Automated change: Fix sanity tests
* lower bound for timer interval
* consistently apply grpc_test_slowdown_factor()
* cache time in test
* add blackout_period tests
* avoid some unnecessary copies
* clang-format
* add field to config test
* simplify orca watcher tracking
* attempt to fix build
* iwyu
* generate_projects
* add "_experimental" suffix to policy name
* WRR: update tests to cover qps plumbing
* WIP
* more WIP
* basic WRR e2e test working
* add OOB test
* fix sanity
* ignore duplicate addresses
* Automated change: Fix sanity tests
* add new tracer to doc/environment_variables.md
* retain scheduler state across pickers
* Automated change: Fix sanity tests
* use separate mutexes for scheduler and timer
* sort addresses to avoid index churn
* remove fetch_sub for wrap around in RR case
Co-authored-by: markdroth <markdroth@users.noreply.github.com>
Xuan Wang
Mark D. Roth
Yash Tibrewal
Esun Kim
Eugene Ostroukhov
Stanley Cheung
Terry Wilson
Akshay Shah
Terry Wilson
Sergii Tkachenko
AJ Heller
Craig Tiller
Jan Tattermusch
Clément Jean
Richard Belleville
Cheng-Yu Chung
tony
Michael Lumish
apolcyn
ktr
Jundol
yifeizhuang