[round robin] delegate to pick_first instead of creating subchannels …

…directly (grpc#32692) More work on the dualstack backend design: - Change round_robin to delegate to pick_first instead of creating subchannels directly. - Change pick_first such that when it is the child of a petiole policy, it will unconditionally start a health watch. - Change the client-side health checking code such that if client-side health checking is not enabled, it will return the subchannel's raw connectivity state. - As part of this, we introduce a new endpoint_list library to be used by petiole policies, which is intended to replace the existing subchannel_list library. The only policy that will still directly interact with subchannels is pick_first, so the relevant parts of the subchannel_list functionality have been copied directly into that policy. The subchannel_list library will be removed after all petiole policies are updated to delegate to pick_first.
alexeykudinkin · Jun 27, 2023 · 27a778f · 27a778f
1 parent 875b7fd
commit 27a778f
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diff --git a/CMakeLists.txt b/CMakeLists.txt
diff --git a/Makefile b/Makefile
diff --git a/Package.swift b/Package.swift
@@ -148,6 +148,8 @@ let package = Package(
         "src/core/ext/filters/client_channel/lb_policy/backend_metric_data.h",
         "src/core/ext/filters/client_channel/lb_policy/child_policy_handler.cc",
         "src/core/ext/filters/client_channel/lb_policy/child_policy_handler.h",
+        "src/core/ext/filters/client_channel/lb_policy/endpoint_list.cc",
+        "src/core/ext/filters/client_channel/lb_policy/endpoint_list.h",
         "src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.cc",
         "src/core/ext/filters/client_channel/lb_policy/grpclb/client_load_reporting_filter.h",
         "src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc",
@@ -167,6 +169,7 @@ let package = Package(
         "src/core/ext/filters/client_channel/lb_policy/outlier_detection/outlier_detection.cc",
         "src/core/ext/filters/client_channel/lb_policy/outlier_detection/outlier_detection.h",
         "src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc",
+        "src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.h",
         "src/core/ext/filters/client_channel/lb_policy/priority/priority.cc",
         "src/core/ext/filters/client_channel/lb_policy/ring_hash/ring_hash.cc",
         "src/core/ext/filters/client_channel/lb_policy/ring_hash/ring_hash.h",

diff --git a/build_autogenerated.yaml b/build_autogenerated.yaml
diff --git a/config.m4 b/config.m4
diff --git a/config.w32 b/config.w32
diff --git a/gRPC-C++.podspec b/gRPC-C++.podspec
diff --git a/gRPC-Core.podspec b/gRPC-Core.podspec
diff --git a/grpc.gemspec b/grpc.gemspec
diff --git a/grpc.gyp b/grpc.gyp
diff --git a/package.xml b/package.xml