xDS: add version gauge

docs/configuration/cluster_manager/cds.rst

@@ -59,6 +59,8 @@ CDS has a statistics tree rooted at *cluster_manager.cds.* with the following st
   :header: Name, Type, Description
   :widths: 1, 1, 2
 
+  config_reload, Counter, Total API fetches that resulted in a config reload due to a different config
   update_attempt, Counter, Total API fetches attempted
   update_success, Counter, Total API fetches completed successfully
   update_failure, Counter, Total API fetches that failed (either network or schema errors)
+  version, Gauge, Hash of the contents from the last successful API fetch

docs/configuration/cluster_manager/cluster_stats.rst

@@ -61,9 +61,11 @@ Every cluster has a statistics tree rooted at *cluster.<name>.* with the followi
   membership_healthy, Gauge, Current cluster healthy total (inclusive of both health checking and outlier detection)
   membership_total, Gauge, Current cluster membership total
   retry_or_shadow_abandoned, Counter, Total number of times shadowing or retry buffering was canceled due to buffer limits.
+  config_reload, Counter, Total API fetches that resulted in a config reload due to a different config
   update_attempt, Counter, Total cluster membership update attempts
   update_success, Counter, Total cluster membership update successes
   update_failure, Counter, Total cluster membership update failures
+  version, Gauge, Hash of the contents from the last successful API fetch
   max_host_weight, Gauge, Maximum weight of any host in the cluster
   bind_errors, Counter, Total errors binding the socket to the configured source address.
 

docs/configuration/http_conn_man/rds.rst

@@ -69,7 +69,9 @@ will only perform a full reload if the hash value changes.
 Statistics
 ----------
 
-RDS has a statistics tree rooted at *http.<stat_prefix>.rds.* with the following statistics:
+RDS has a statistics tree rooted at *http.<stat_prefix>.rds.<route_config_name>.*.
+Any ``:`` character in the ``route_config_name`` name gets replaced with ``_`` in the
+stats tree. The stats tree contains the following statistics:
 
 .. csv-table::
   :header: Name, Type, Description
@@ -79,3 +81,4 @@ RDS has a statistics tree rooted at *http.<stat_prefix>.rds.* with the following
   update_attempt, Counter, Total API fetches attempted
   update_success, Counter, Total API fetches completed successfully
   update_failure, Counter, Total API fetches that failed (either network or schema errors)
+  version, Gauge, Hash of the contents from the last successful API fetch

docs/configuration/listeners/lds.rst

@@ -77,6 +77,8 @@ LDS has a statistics tree rooted at *listener_manager.lds.* with the following s
   :header: Name, Type, Description
   :widths: 1, 1, 2
 
+  config_reload, Counter, Total API fetches that resulted in a config reload due to a different config
   update_attempt, Counter, Total API fetches attempted
   update_success, Counter, Total API fetches completed successfully
   update_failure, Counter, Total API fetches that failed (either network or schema errors)
+  version, Gauge, Hash of the contents from the last successful API fetch

include/envoy/config/subscription.h

@@ -75,18 +75,19 @@ template <class ResourceType> class Subscription {
  * Per subscription stats. @see stats_macros.h
  */
 // clang-format off
-#define ALL_SUBSCRIPTION_STATS(COUNTER) \
-  COUNTER(update_attempt)               \
-  COUNTER(update_success)               \
-  COUNTER(update_failure)               \
-  COUNTER(update_rejected)
+#define ALL_SUBSCRIPTION_STATS(COUNTER, GAUGE) \
+  COUNTER(update_attempt)                      \
+  COUNTER(update_success)                      \
+  COUNTER(update_failure)                      \
+  COUNTER(update_rejected)                     \
+  GAUGE(version)
 // clang-format on
 
 /**
  * Struct definition for per subscription stats. @see stats_macros.h
  */
 struct SubscriptionStats {
-  ALL_SUBSCRIPTION_STATS(GENERATE_COUNTER_STRUCT)
+  ALL_SUBSCRIPTION_STATS(GENERATE_COUNTER_STRUCT, GENERATE_GAUGE_STRUCT)
 };
 
 } // namespace Config

include/envoy/upstream/upstream.h

@@ -235,7 +235,8 @@ class HostSet {
   COUNTER(update_attempt)                                                                          \
   COUNTER(update_success)                                                                          \
   COUNTER(update_failure)                                                                          \
-  COUNTER(update_empty)
+  COUNTER(update_empty)                                                                            \
+  GAUGE(version)
 
 // clang-format on
 

source/common/config/filesystem_subscription_impl.h

@@ -63,6 +63,7 @@ class FilesystemSubscriptionImpl : public Config::Subscription<ResourceType>,
       config_update_available = true;
       callbacks_->onConfigUpdate(typed_resources);
       version_info_ = message.version_info();
+      stats_.version_.set(HashUtil::xxHash64(version_info_));
       stats_.update_success_.inc();
       ENVOY_LOG(debug, "Filesystem config update accepted for {}: {}", path_,
                 message.DebugString());

source/common/config/grpc_mux_subscription_impl.h

@@ -55,6 +55,7 @@ class GrpcMuxSubscriptionImpl : public Subscription<ResourceType>,
     stats_.update_success_.inc();
     stats_.update_attempt_.inc();
     version_info_ = version_info;
+    stats_.version_.set(HashUtil::xxHash64(version_info_));
     ENVOY_LOG(debug, "gRPC config for {} accepted with {} resources", type_url_, resources.size());
 
 #ifndef NVLOG

source/common/config/http_subscription_impl.h

@@ -83,6 +83,7 @@ class HttpSubscriptionImpl : public Http::RestApiFetcher,
     try {
       callbacks_->onConfigUpdate(typed_resources);
       request_.set_version_info(message.version_info());
+      stats_.version_.set(HashUtil::xxHash64(request_.version_info()));
       stats_.update_success_.inc();
     } catch (const EnvoyException& e) {
       ENVOY_LOG(warn, "REST config update rejected: {}", e.what());

source/common/config/utility.h

@@ -5,6 +5,7 @@
 #include "envoy/json/json_object.h"
 #include "envoy/local_info/local_info.h"
 #include "envoy/registry/registry.h"
+#include "envoy/stats/stats.h"
 #include "envoy/upstream/cluster_manager.h"
 
 #include "common/common/assert.h"
@@ -59,11 +60,15 @@ class Utility {
   }
 
   /**
-   * Legacy APIs uses JSON and do not have an explicit version. Hash the body and append
-   * a user-friendly prefix.
+   * Legacy APIs uses JSON and do not have an explicit version.
+   * @param input the input to hash.
+   * @return std::pair<std::string, uint64_t> the string is the hash converted into
+   *         a hex string, pre-pended by a user friendly prefix. The uint64_t is the
+   *         raw hash.
    */
-  static std::string computeHashedVersion(const std::string& input) {
-    return "hash_" + Hex::uint64ToHex(HashUtil::xxHash64(input));
+  static std::pair<std::string, uint64_t> computeHashedVersion(const std::string& input) {
+    uint64_t hash = HashUtil::xxHash64(input);
+    return std::make_pair("hash_" + Hex::uint64ToHex(hash), hash);
   }
 
   /**
@@ -149,7 +154,7 @@ class Utility {
    * @return SubscriptionStats for scope.
    */
   static SubscriptionStats generateStats(Stats::Scope& scope) {
-    return {ALL_SUBSCRIPTION_STATS(POOL_COUNTER(scope))};
+    return {ALL_SUBSCRIPTION_STATS(POOL_COUNTER(scope), POOL_GAUGE(scope))};
   }
 
   /**

source/common/router/rds_impl.cc

@@ -47,7 +47,8 @@ RdsRouteConfigProviderImpl::RdsRouteConfigProviderImpl(
     const std::string& stat_prefix, ThreadLocal::SlotAllocator& tls,
     RouteConfigProviderManagerImpl& route_config_provider_manager)
     : runtime_(runtime), cm_(cm), tls_(tls.allocateSlot()),
-      route_config_name_(rds.route_config_name()), scope_(scope.createScope(stat_prefix + "rds.")),
+      route_config_name_(rds.route_config_name()),
+      scope_(scope.createScope(stat_prefix + "rds." + route_config_name_ + ".")),
       stats_({ALL_RDS_STATS(POOL_COUNTER(*scope_))}),
       route_config_provider_manager_(route_config_provider_manager),
       manager_identifier_(manager_identifier) {

source/common/router/rds_subscription.cc

@@ -49,7 +49,10 @@ void RdsSubscription::parseResponse(const Http::Message& response) {
   Envoy::Config::RdsJson::translateRouteConfiguration(*response_json, *resources.Add());
   resources[0].set_name(route_config_name_);
   callbacks_->onConfigUpdate(resources);
-  version_info_ = Envoy::Config::Utility::computeHashedVersion(response_body);
+  std::pair<std::string, uint64_t> hash =
+      Envoy::Config::Utility::computeHashedVersion(response_body);
+  version_info_ = hash.first;
+  stats_.version_.set(hash.second);
   stats_.update_success_.inc();
 }
 

source/common/upstream/cds_subscription.cc

@@ -52,7 +52,10 @@ void CdsSubscription::parseResponse(const Http::Message& response) {
   }
 
   callbacks_->onConfigUpdate(resources);
-  version_info_ = Config::Utility::computeHashedVersion(response_body);
+  std::pair<std::string, uint64_t> hash =
+      Envoy::Config::Utility::computeHashedVersion(response_body);
+  version_info_ = hash.first;
+  stats_.version_.set(hash.second);
   stats_.update_success_.inc();
 }
 

source/common/upstream/sds_subscription.cc

@@ -73,7 +73,10 @@ void SdsSubscription::parseResponse(const Http::Message& response) {
   }
 
   callbacks_->onConfigUpdate(resources);
-  version_info_ = Config::Utility::computeHashedVersion(response_body);
+  std::pair<std::string, uint64_t> hash =
+      Envoy::Config::Utility::computeHashedVersion(response_body);
+  version_info_ = hash.first;
+  stats_.version_.set(hash.second);
   stats_.update_success_.inc();
 }
 

source/server/lds_subscription.cc

@@ -52,7 +52,10 @@ void LdsSubscription::parseResponse(const Http::Message& response) {
   }
 
   callbacks_->onConfigUpdate(resources);
-  version_info_ = Config::Utility::computeHashedVersion(response_body);
+  std::pair<std::string, uint64_t> hash =
+      Envoy::Config::Utility::computeHashedVersion(response_body);
+  version_info_ = hash.first;
+  stats_.version_.set(hash.second);
   stats_.update_success_.inc();
 }
 

test/common/config/filesystem_subscription_impl_test.cc

@@ -12,19 +12,19 @@ class FilesystemSubscriptionImplTest : public FilesystemSubscriptionTestHarness,
 // Validate that the client can recover from bad JSON responses.
 TEST_F(FilesystemSubscriptionImplTest, BadJsonRecovery) {
   startSubscription({"cluster0", "cluster1"});
-  verifyStats(1, 0, 0, 0);
+  verifyStats(1, 0, 0, 0, 0);
   EXPECT_CALL(callbacks_, onConfigUpdateFailed(_));
   updateFile(";!@#badjso n");
-  verifyStats(2, 0, 0, 1);
+  verifyStats(2, 0, 0, 1, 0);
   deliverConfigUpdate({"cluster0", "cluster1"}, "0", true);
-  verifyStats(3, 1, 0, 1);
+  verifyStats(3, 1, 0, 1, 7148434200721666028);
 }
 
 // Validate that a file that is initially available results in a successful update.
 TEST_F(FilesystemSubscriptionImplTest, InitialFile) {
   updateFile("{\"versionInfo\": \"0\", \"resources\": []}", false);
   startSubscription({"cluster0", "cluster1"});
-  verifyStats(1, 1, 0, 0);
+  verifyStats(1, 1, 0, 0, 7148434200721666028);
 }
 
 } // namespace

test/common/config/filesystem_subscription_test_harness.h

@@ -83,11 +83,11 @@ class FilesystemSubscriptionTestHarness : public SubscriptionTestHarness {
     EXPECT_EQ(version_, subscription_.versionInfo());
   }
 
-  void verifyStats(uint32_t attempt, uint32_t success, uint32_t rejected,
-                   uint32_t failure) override {
+  void verifyStats(uint32_t attempt, uint32_t success, uint32_t rejected, uint32_t failure,
+                   uint64_t version) override {
     // The first attempt always fail unless there was a file there to begin with.
     SubscriptionTestHarness::verifyStats(attempt, success, rejected,
-                                         failure + (file_at_start_ ? 0 : 1));
+                                         failure + (file_at_start_ ? 0 : 1), version);
   }
 
   const std::string path_;

test/common/config/grpc_subscription_impl_test.cc

@@ -17,54 +17,54 @@ TEST_F(GrpcSubscriptionImplTest, StreamCreationFailure) {
   EXPECT_CALL(callbacks_, onConfigUpdateFailed(_));
   EXPECT_CALL(*timer_, enableTimer(_));
   subscription_->start({"cluster0", "cluster1"}, callbacks_);
-  verifyStats(2, 0, 0, 1);
+  verifyStats(2, 0, 0, 1, 0);
   // Ensure this doesn't cause an issue by sending a request, since we don't
   // have a gRPC stream.
   subscription_->updateResources({"cluster2"});
   // Retry and succeed.
   EXPECT_CALL(*async_client_, start(_, _)).WillOnce(Return(&async_stream_));
   expectSendMessage({"cluster2"}, "");
   timer_cb_();
-  verifyStats(3, 0, 0, 1);
+  verifyStats(3, 0, 0, 1, 0);
 }
 
 // Validate that the client can recover from a remote stream closure via retry.
 TEST_F(GrpcSubscriptionImplTest, RemoteStreamClose) {
   startSubscription({"cluster0", "cluster1"});
-  verifyStats(1, 0, 0, 0);
+  verifyStats(1, 0, 0, 0, 0);
   Http::HeaderMapPtr trailers{new Http::TestHeaderMapImpl{}};
   subscription_->grpcMux().onReceiveTrailingMetadata(std::move(trailers));
   EXPECT_CALL(*timer_, enableTimer(_));
   EXPECT_CALL(callbacks_, onConfigUpdateFailed(_));
   subscription_->grpcMux().onRemoteClose(Grpc::Status::GrpcStatus::Canceled, "");
-  verifyStats(2, 0, 0, 1);
+  verifyStats(2, 0, 0, 1, 0);
   // Retry and succeed.
   EXPECT_CALL(*async_client_, start(_, _)).WillOnce(Return(&async_stream_));
   expectSendMessage({"cluster0", "cluster1"}, "");
   timer_cb_();
-  verifyStats(2, 0, 0, 1);
+  verifyStats(2, 0, 0, 1, 0);
 }
 
 // Validate that When the management server gets multiple requests for the same version, it can
 // ignore later ones. This allows the nonce to be used.
 TEST_F(GrpcSubscriptionImplTest, RepeatedNonce) {
   InSequence s;
   startSubscription({"cluster0", "cluster1"});
-  verifyStats(1, 0, 0, 0);
+  verifyStats(1, 0, 0, 0, 0);
   // First with the initial, empty version update to "0".
   updateResources({"cluster2"});
-  verifyStats(2, 0, 0, 0);
+  verifyStats(2, 0, 0, 0, 0);
   deliverConfigUpdate({"cluster0", "cluster2"}, "0", false);
-  verifyStats(3, 0, 1, 0);
+  verifyStats(3, 0, 1, 0, 0);
   deliverConfigUpdate({"cluster0", "cluster2"}, "0", true);
-  verifyStats(4, 1, 1, 0);
+  verifyStats(4, 1, 1, 0, 7148434200721666028);
   // Now with version "0" update to "1".
   updateResources({"cluster3"});
-  verifyStats(5, 1, 1, 0);
+  verifyStats(5, 1, 1, 0, 7148434200721666028);
   deliverConfigUpdate({"cluster3"}, "1", false);
-  verifyStats(6, 1, 2, 0);
+  verifyStats(6, 1, 2, 0, 7148434200721666028);
   deliverConfigUpdate({"cluster3"}, "1", true);
-  verifyStats(7, 2, 2, 0);
+  verifyStats(7, 2, 2, 0, 13237225503670494420U);
 }
 
 } // namespace

test/common/config/http_subscription_impl_test.cc

@@ -15,11 +15,11 @@ TEST_F(HttpSubscriptionImplTest, OnRequestReset) {
   EXPECT_CALL(*timer_, enableTimer(_));
   EXPECT_CALL(callbacks_, onConfigUpdateFailed(_));
   http_callbacks_->onFailure(Http::AsyncClient::FailureReason::Reset);
-  verifyStats(1, 0, 0, 1);
+  verifyStats(1, 0, 0, 1, 0);
   timerTick();
-  verifyStats(2, 0, 0, 1);
+  verifyStats(2, 0, 0, 1, 0);
   deliverConfigUpdate({"cluster0", "cluster1"}, "0", true);
-  verifyStats(3, 1, 0, 1);
+  verifyStats(3, 1, 0, 1, 7148434200721666028);
 }
 
 // Validate that the client can recover from bad JSON responses.
@@ -32,12 +32,12 @@ TEST_F(HttpSubscriptionImplTest, BadJsonRecovery) {
   EXPECT_CALL(*timer_, enableTimer(_));
   EXPECT_CALL(callbacks_, onConfigUpdateFailed(_));
   http_callbacks_->onSuccess(std::move(message));
-  verifyStats(1, 0, 0, 1);
+  verifyStats(1, 0, 0, 1, 0);
   request_in_progress_ = false;
   timerTick();
-  verifyStats(2, 0, 0, 1);
+  verifyStats(2, 0, 0, 1, 0);
   deliverConfigUpdate({"cluster0", "cluster1"}, "0", true);
-  verifyStats(3, 1, 0, 1);
+  verifyStats(3, 1, 0, 1, 7148434200721666028);
 }
 
 } // namespace