Add keepalive params to Envoy alts transport socket (#40195)

Commit Message: Add keepalive params to Envoy alts transport socket
Additional Description:
Add environment variable-protected gRPC keepalive params for the ALTS
handshake client.

Risk Level: low
Testing: N/A
Docs Changes: N/A
Release Notes: N/A
Platform Specific Features: N/A

---------

Signed-off-by: Luwei Ge <[email protected]>

Author: rockspore

changelogs/current.yaml

@@ -370,5 +370,8 @@ new_features:
     flag to HTTP Dynamic Forward Proxy filter. When enabled, the filter will check for ``envoy.upstream.dynamic_host`` and
     ``envoy.upstream.dynamic_port`` filter state values before using the HTTP Host header, providing consistency with SNI
     and UDP DFP filters. When disabled (default), maintains backward compatibility by using the HTTP Host header directly.
+- area: alts
+  change: |
+    Added environment variable-protected gRPC keepalive params to the ALTS handshaker client.
 
 deprecated:

source/extensions/transport_sockets/alts/alts_channel_pool.cc

@@ -1,6 +1,7 @@
 #include "source/extensions/transport_sockets/alts/alts_channel_pool.h"
 
 #include <algorithm>
+#include <cstring>
 #include <memory>
 #include <string>
 #include <utility>
@@ -20,13 +21,25 @@ namespace Alts {
 
 // TODO(matthewstevenson88): Extend this to be configurable through API.
 constexpr std::size_t ChannelPoolSize = 10;
+constexpr char UseGrpcExperimentalAltsHandshakerKeepaliveParams[] =
+    "GRPC_EXPERIMENTAL_ALTS_HANDSHAKER_KEEPALIVE_PARAMS";
+
+// 10 seconds
+constexpr int ExperimentalKeepAliveTimeoutMs = 10 * 1000;
+// 10 minutes
+constexpr int ExperimentalKeepAliveTimeMs = 10 * 60 * 1000;
 
 std::unique_ptr<AltsChannelPool>
 AltsChannelPool::create(absl::string_view handshaker_service_address) {
   std::vector<std::shared_ptr<grpc::Channel>> channel_pool;
   channel_pool.reserve(ChannelPoolSize);
   grpc::ChannelArguments channel_args;
   channel_args.SetInt(GRPC_ARG_USE_LOCAL_SUBCHANNEL_POOL, 1);
+  const char* keep_alive = std::getenv(UseGrpcExperimentalAltsHandshakerKeepaliveParams);
+  if (keep_alive != nullptr && std::strcmp(keep_alive, "true") == 0) {
+    channel_args.SetInt(GRPC_ARG_KEEPALIVE_TIMEOUT_MS, ExperimentalKeepAliveTimeoutMs);
+    channel_args.SetInt(GRPC_ARG_KEEPALIVE_TIME_MS, ExperimentalKeepAliveTimeMs);
+  }
   for (std::size_t i = 0; i < ChannelPoolSize; ++i) {
     channel_pool.push_back(grpc::CreateCustomChannel(
         std::string(handshaker_service_address), grpc::InsecureChannelCredentials(), channel_args));

test/extensions/transport_sockets/alts/alts_channel_pool_test.cc

@@ -1,3 +1,5 @@
+#include <stdlib.h>
+
 #include <memory>
 #include <string>
 #include <thread>
@@ -115,6 +117,32 @@ TEST_P(AltsChannelPoolTest, SuccessWithDefaultChannels) {
   }
 }
 
+TEST_P(AltsChannelPoolTest, SuccessWithDefaultChannelsWithKeepAliveParams) {
+  startFakeHandshakerService();
+
+  setenv("GRPC_EXPERIMENTAL_ALTS_HANDSHAKER_KEEPALIVE_PARAMS", "true", 1);
+  // Create a channel pool and check that it has the correct dimensions.
+  auto channel_pool = AltsChannelPool::create(serverAddress());
+  EXPECT_THAT(channel_pool, NotNull());
+  EXPECT_THAT(channel_pool->getChannel(), NotNull());
+  EXPECT_EQ(channel_pool->getChannelPoolSize(), 10);
+
+  // Check that we can write to and read from the channel multiple times.
+  for (int i = 0; i < 10; ++i) {
+    auto channel = channel_pool->getChannel();
+    EXPECT_THAT(channel, NotNull());
+    grpc::ClientContext client_context;
+    auto stub = HandshakerService::NewStub(channel);
+    auto stream = stub->DoHandshake(&client_context);
+    HandshakerReq request;
+    EXPECT_TRUE(stream->Write(request));
+    HandshakerResp response;
+    EXPECT_TRUE(stream->Read(&response));
+  }
+
+  unsetenv("GRPC_EXPERIMENTAL_ALTS_HANDSHAKER_KEEPALIVE_PARAMS");
+}
+
 } // namespace
 } // namespace Alts
 } // namespace TransportSockets