Use listening mode for Apollo configuration. (#11186)

Author: weixiang1862

docs/en/changes/changes.md

@@ -65,7 +65,8 @@
 * Remove ElasticSearch 6.3.2 from our client lib tests.
 * Bump up ElasticSearch server 8.8.1 to 8.9.0 for latest e2e testing. 8.1.0, 7.16.3 and 7.17.10 are still tested.
 * Add OpenSearch 2.8.0 to our client lib tests.
-* Apply MQE on RabbitMQ Dashboards
+* Apply MQE on RabbitMQ Dashboards.
+* Use listening mode for apollo implementation of dynamic configuration.
 
 
 #### UI

docs/en/setup/backend/configuration-vocabulary.md

@@ -273,7 +273,6 @@ The Configuration Vocabulary lists all available configurations provided by `app
 | -                       | -             | apolloCluster                                                                                                                                                            | `apollo.cluster` in Apollo.                                                                                                                                                                                                                                                                                                                                                                                                                                                | SW_CONFIG_APOLLO_CLUSTER                              | default                                                                                      |
 | -                       | -             | apolloEnv                                                                                                                                                                | `env` in Apollo.                                                                                                                                                                                                                                                                                                                                                                                                                                                           | SW_CONFIG_APOLLO_ENV                                  | -                                                                                            |
 | -                       | -             | appId                                                                                                                                                                    | `app.id` in Apollo.                                                                                                                                                                                                                                                                                                                                                                                                                                                        | SW_CONFIG_APOLLO_APP_ID                               | skywalking                                                                                   |
-| -                       | -             | period                                                                                                                                                                   | The period of data sync (in seconds).                                                                                                                                                                                                                                                                                                                                                                                                                                      | SW_CONFIG_APOLLO_PERIOD                               | 60                                                                                           |
 | -                       | zookeeper     | namespace                                                                                                                                                                | The namespace (represented by root path) that isolates the configurations in the Zookeeper.                                                                                                                                                                                                                                                                                                                                                                                | SW_CONFIG_ZK_NAMESPACE                                | `/`, root path                                                                               |
 | -                       | -             | hostPort                                                                                                                                                                 | Hosts and ports of Zookeeper Cluster.                                                                                                                                                                                                                                                                                                                                                                                                                                      | SW_CONFIG_ZK_HOST_PORT                                | localhost:2181                                                                               |
 | -                       | -             | baseSleepTimeMs                                                                                                                                                          | The period of Zookeeper client between two retries (in milliseconds).                                                                                                                                                                                                                                                                                                                                                                                                      | SW_CONFIG_ZK_BASE_SLEEP_TIME_MS                       | 1000                                                                                         |

docs/en/setup/backend/dynamic-config-apollo.md

@@ -10,7 +10,6 @@ configuration:
     apolloCluster: ${SW_CONFIG_APOLLO_CLUSTER:default}
     apolloEnv: ${SW_CONFIG_APOLLO_ENV:""}
     appId: ${SW_CONFIG_APOLLO_APP_ID:skywalking}
-    period: ${SW_CONFIG_APOLLO_PERIOD:60}
 ```
 
 ## Config Storage

oap-server/analyzer/agent-analyzer/src/test/java/org/apache/skywalking/oap/server/analyzer/provider/trace/TraceSamplingPolicyWatcherTest.java

@@ -25,6 +25,7 @@
 import org.apache.skywalking.oap.server.configuration.api.ConfigChangeWatcher;
 import org.apache.skywalking.oap.server.configuration.api.ConfigTable;
 import org.apache.skywalking.oap.server.configuration.api.ConfigWatcherRegister;
+import org.apache.skywalking.oap.server.configuration.api.FetchingConfigWatcherRegister;
 import org.apache.skywalking.oap.server.configuration.api.GroupConfigTable;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.BeforeEach;
@@ -121,7 +122,7 @@ public void testTraceLatencyThresholdNotify() {
             "  duration: 800");
     }
 
-    public static class TraceLatencyThresholdMockConfigWatcherRegister extends ConfigWatcherRegister {
+    public static class TraceLatencyThresholdMockConfigWatcherRegister extends FetchingConfigWatcherRegister {
 
         public TraceLatencyThresholdMockConfigWatcherRegister(long syncPeriod) {
             super(syncPeriod);
@@ -205,7 +206,7 @@ public void testDefaultSampleRateNotify() {
             "  rate: 500");
     }
 
-    public static class DefaultSampleRateMockConfigWatcherRegister extends ConfigWatcherRegister {
+    public static class DefaultSampleRateMockConfigWatcherRegister extends FetchingConfigWatcherRegister {
 
         public DefaultSampleRateMockConfigWatcherRegister(long syncPeriod) {
             super(syncPeriod);
@@ -335,7 +336,7 @@ public void testServiceSampleRateNotify() {
 
     }
 
-    public static class ServiceMockConfigWatcherRegister extends ConfigWatcherRegister {
+    public static class ServiceMockConfigWatcherRegister extends FetchingConfigWatcherRegister {
 
         public ServiceMockConfigWatcherRegister(long syncPeriod) {
             super(syncPeriod);