Verify committed global config via bgpd getRunningConfig RPC

The commit-path global-attribute tests asserted on the promoted
/etc/coop/bgpcpp/bgpcpp.conf, which only proves what the CLI wrote to disk.
Route ConfigBgpTestBase::setAndCommit() through a new
readRunningBgpConfigViaRpc() -- TBgpService::getRunningConfig against the local
bgpd -- so every positive ConfigBgpGlobalTest asserts its attribute in the
daemon's own view of its config, proving bgpd parsed and adopted the promoted
file after the commit-triggered restart.

The helper retries briefly on connection errors: systemd reports bgpd active as
soon as the process starts, but its thrift server binds the port a few seconds
later, so an RPC issued right after a restart races that window.

Test Plan:
- bazel build //fboss/cli/fboss2/test/integration_test:fboss2_integration_test
- fboss2_integration_test on a DUT with bgpd active: ConfigBgpGlobalTest 7/7
  pass (each attribute set+commit verified in bgpd's getRunningConfig view,
  plus the invalid-bool and negative-graceful-restart-time reject paths).

Author: hillol-nexthop

fboss/cli/fboss2/test/integration_test/BUCK

@@ -13,6 +13,7 @@ oncall("fboss_oss")
 #
 # Unlike the Python-based CLI tests, these C++ tests directly invoke the CLI
 # library code rather than spawning a subprocess.
+# bazelify: extra_dep = //neteng/fboss/bgp/if:bgp_thrift
 cpp_binary(
     name = "fboss2_integration_test",
     srcs = [

fboss/cli/fboss2/test/integration_test/ConfigBgpGlobalTest.cpp

@@ -5,9 +5,12 @@
  *
  * Scope: the BGP *global* tunables only. Each positive test stages the change
  * AND commits it, then asserts the value landed at the correct thrift field
- * path in the promoted system config (/etc/coop/bgpcpp/bgpcpp.conf) that the
- * bgpd daemon consumes. Session-lifecycle behavior (clear / diff / rollback /
- * commit-restart mechanics) lives in ConfigBgpSessionTest.
+ * path in bgpd's own running config — fetched over its getRunningConfig RPC
+ * (see ConfigBgpTestBase::setAndCommit) — which proves the daemon parsed and
+ * adopted the promoted /etc/coop/bgpcpp/bgpcpp.conf after the commit-triggered
+ * restart, not merely that the CLI wrote the file. Session-lifecycle behavior
+ * (clear / diff / rollback / commit-restart mechanics) lives in
+ * ConfigBgpSessionTest.
  *
  *   - count-confeds-in-as-path-len <true|false>
  *       -> BgpConfig.count_confeds_in_as_path_len

fboss/cli/fboss2/test/integration_test/ConfigBgpTestBase.h

@@ -28,6 +28,8 @@
 #include <thread>
 
 #include "fboss/cli/fboss2/test/integration_test/Fboss2IntegrationTest.h"
+#include "fboss/cli/fboss2/utils/CmdClientUtilsCommon.h"
+#include "neteng/fboss/bgp/if/gen-cpp2/TBgpService.h"
 
 namespace facebook::fboss {
 
@@ -78,6 +80,36 @@ class ConfigBgpTestBase : public Fboss2IntegrationTest {
     return folly::parseJson(content);
   }
 
+  // The running config as reported by the bgpd daemon itself, over its
+  // TBgpService::getRunningConfig thrift RPC. Unlike readSystemBgpConfig()
+  // (the promoted file on disk, which only proves what the CLI wrote), this
+  // proves the daemon parsed and adopted the config after the post-commit
+  // restart. Mirrors Fboss2IntegrationTest::getRunningConfig() for the agent.
+  //
+  // Retries on connection errors: systemd reports bgpd "active" as soon as
+  // the process starts, but the thrift server only binds its port a few
+  // seconds later — an RPC issued right after a commit-triggered restart
+  // would otherwise race that window and get ECONNREFUSED.
+  folly::dynamic readRunningBgpConfigViaRpc(
+      std::chrono::seconds timeout = std::chrono::seconds(30)) const {
+    auto deadline = std::chrono::steady_clock::now() + timeout;
+    while (true) {
+      try {
+        HostInfo hostInfo("localhost");
+        auto client = utils::createClient<apache::thrift::Client<
+            facebook::neteng::fboss::bgp::thrift::TBgpService>>(hostInfo);
+        std::string configStr;
+        client->sync_getRunningConfig(configStr);
+        return folly::parseJson(configStr);
+      } catch (const std::exception&) {
+        if (std::chrono::steady_clock::now() >= deadline) {
+          throw;
+        }
+        std::this_thread::sleep_for(std::chrono::seconds(1));
+      }
+    }
+  }
+
   // Root of the git repo that versions both the agent config (cli/agent.conf)
   // and the BGP config (bgpcpp/bgpcpp.conf).
   std::string coopRepoDir() const {
@@ -162,10 +194,19 @@ class ConfigBgpTestBase : public Fboss2IntegrationTest {
   }
 
   // Stage a global change, commit it, wait for bgpd to come back, and return
-  // the promoted system config (the authoritative post-commit location).
-  // A no-op commit (staged value already in the system config) yields no SHA
-  // and is fine: the caller's assertions on the returned config still verify
-  // the value; commit/restart mechanics are covered by ConfigBgpSessionTest.
+  // bgpd's own running config as reported over its getRunningConfig RPC.
+  //
+  // The returned config is the daemon's adopted view, which is strictly
+  // stronger than the promoted file on disk (readSystemBgpConfig): a value
+  // present here proves the commit promoted /etc/coop/bgpcpp/bgpcpp.conf AND
+  // that bgpd parsed and adopted it after the commit-triggered restart, not
+  // merely that the CLI wrote the file. The running config shares the same
+  // BgpConfig JSON schema as the promoted file, so callers assert the same
+  // field paths against it.
+  //
+  // A no-op commit (staged value already current) yields no SHA and is fine:
+  // the caller's assertions on the returned config still verify the value;
+  // commit/restart mechanics are covered by ConfigBgpSessionTest.
   folly::dynamic setAndCommit(const std::string& attr, const std::string& value)
       const {
     discardSession();
@@ -174,7 +215,7 @@ class ConfigBgpTestBase : public Fboss2IntegrationTest {
     EXPECT_TRUE(waitForBgpDaemonActive())
         << "bgpd did not return active after commit; state="
         << bgpDaemonActiveState();
-    return readSystemBgpConfig();
+    return readRunningBgpConfigViaRpc();
   }
 
   // Trailing-whitespace-trimmed stdout of a `systemctl` query for bgpd.