App config Revision retry after (Azure#20108)

* Adds dependency to add boostrap support in Spring Boot 2.4

* Fixed spacing

* Adding Retry after for revisions endpoint.

* Updated to reuse clients, updated to use HttpSatus for status code.

* Added check for revisions returning at least 1 result

Author: mrm9084

sdk/appconfiguration/spring-cloud-azure-appconfiguration-config/src/main/java/com/microsoft/azure/spring/cloud/config/stores/ClientStore.java

@@ -8,20 +8,23 @@
 import java.io.IOException;
 import java.time.Duration;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
-import java.util.stream.Collectors;
 
 import org.apache.commons.lang3.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.http.HttpStatus;
 import org.springframework.lang.NonNull;
 import org.springframework.lang.Nullable;
 
 import com.azure.core.credential.TokenCredential;
+import com.azure.core.http.HttpHeader;
 import com.azure.core.http.policy.ExponentialBackoff;
 import com.azure.core.http.policy.RetryPolicy;
+import com.azure.core.http.rest.PagedResponse;
 import com.azure.data.appconfiguration.ConfigurationAsyncClient;
 import com.azure.data.appconfiguration.ConfigurationClientBuilder;
 import com.azure.data.appconfiguration.models.ConfigurationSetting;
@@ -45,21 +48,27 @@ public class ClientStore {
 
     private ConfigurationClientBuilderSetup clientProvider;
 
+    private HashMap<String, ConfigurationAsyncClient> clients;
+
     public ClientStore(AppConfigurationProviderProperties appProperties, ConnectionPool pool,
-            AppConfigurationCredentialProvider tokenCredentialProvider,
-            ConfigurationClientBuilderSetup clientProvider) {
+        AppConfigurationCredentialProvider tokenCredentialProvider,
+        ConfigurationClientBuilderSetup clientProvider) {
         this.appProperties = appProperties;
         this.pool = pool;
         this.tokenCredentialProvider = tokenCredentialProvider;
         this.clientProvider = clientProvider;
+        this.clients = new HashMap<String, ConfigurationAsyncClient>();
     }
 
     private ConfigurationAsyncClient buildClient(String store) throws IllegalArgumentException {
+        if (clients.containsKey(store)) {
+            return clients.get(store);
+        }
         ConfigurationClientBuilder builder = getBuilder();
         ExponentialBackoff retryPolicy = new ExponentialBackoff(appProperties.getMaxRetries(),
-                Duration.ofMillis(800), Duration.ofSeconds(8));
+            Duration.ofMillis(800), Duration.ofSeconds(8));
         builder = builder.addPolicy(new BaseAppConfigurationPolicy()).retryPolicy(new RetryPolicy(
-                retryPolicy));
+            retryPolicy));
 
         TokenCredential tokenCredential = null;
         Connection connection = pool.get(store);
@@ -72,26 +81,26 @@ private ConfigurationAsyncClient buildClient(String store) throws IllegalArgumen
             tokenCredential = tokenCredentialProvider.getAppConfigCredential(endpoint);
         }
         if ((tokenCredential != null
-                || (connection.getClientId() != null && StringUtils.isNotEmpty(connection.getClientId())))
-                && (connection != null && StringUtils.isNotEmpty(connection.getConnectionString()))) {
+            || (connection.getClientId() != null && StringUtils.isNotEmpty(connection.getClientId())))
+            && (connection != null && StringUtils.isNotEmpty(connection.getConnectionString()))) {
             throw new IllegalArgumentException(
-                    "More than 1 Conncetion method was set for connecting to App Configuration.");
+                "More than 1 Conncetion method was set for connecting to App Configuration.");
         } else if (tokenCredential != null && connection != null && connection.getClientId() != null
-                && StringUtils.isNotEmpty(connection.getClientId())) {
+            && StringUtils.isNotEmpty(connection.getClientId())) {
             throw new IllegalArgumentException(
-                    "More than 1 Conncetion method was set for connecting to App Configuration.");
+                "More than 1 Conncetion method was set for connecting to App Configuration.");
         }
 
         if (tokenCredential != null) {
             // User Provided Token Credential
             LOGGER.debug("Connecting to " + endpoint + " using AppConfigurationCredentialProvider.");
             builder.credential(tokenCredential);
         } else if ((connection.getClientId() != null && StringUtils.isNotEmpty(connection.getClientId()))
-                && connection.getEndpoint() != null) {
+            && connection.getEndpoint() != null) {
             // User Assigned Identity - Client ID through configuration file.
             LOGGER.debug("Connecting to " + endpoint + " using Client ID from configuration file.");
             ManagedIdentityCredentialBuilder micBuilder = new ManagedIdentityCredentialBuilder()
-                    .clientId(connection.getClientId());
+                .clientId(connection.getClientId());
             builder.credential(micBuilder.build());
         } else if (StringUtils.isNotEmpty(connection.getConnectionString())) {
             // Connection String
@@ -101,7 +110,7 @@ private ConfigurationAsyncClient buildClient(String store) throws IllegalArgumen
             // System Assigned Identity. Needs to be checked last as all of the above
             // should have a Endpoint.
             LOGGER.debug("Connecting to " + endpoint
-                    + " using Azure System Assigned Identity or Azure User Assigned Identity.");
+                + " using Azure System Assigned Identity or Azure User Assigned Identity.");
             ManagedIdentityCredentialBuilder micBuilder = new ManagedIdentityCredentialBuilder();
             builder.credential(micBuilder.build());
         } else {
@@ -114,47 +123,75 @@ private ConfigurationAsyncClient buildClient(String store) throws IllegalArgumen
             clientProvider.setup(builder, endpoint);
         }
 
-        return builder.buildAsyncClient();
+        clients.put(store, builder.buildAsyncClient());
+        return clients.get(store);
     }
 
     /**
-     * Gets the latest Configuration Setting from the revisions given config store that
-     * match the Setting Selector criteria.
+     * Gets the latest Configuration Setting from the revisions given config store that match the Setting Selector
+     * criteria.
      *
-     * @param settingSelector Information on which setting to pull. i.e. number of
-     * results, key value...
+     * @param settingSelector Information on which setting to pull. i.e. number of results, key value...
      * @param storeName Name of the App Configuration store to query against.
      * @return List of Configuration Settings.
      */
     public final ConfigurationSetting getRevison(SettingSelector settingSelector, String storeName) {
+        PagedResponse<ConfigurationSetting> configurationRevision = null;
+        int retryCount = 0;
+
         ConfigurationAsyncClient client = buildClient(storeName);
-        return client.listRevisions(settingSelector).blockFirst();
+        while (retryCount <= appProperties.getMaxRetries()) {
+            configurationRevision = client.listRevisions(settingSelector).byPage().blockFirst();
+
+            if (configurationRevision != null
+                && configurationRevision.getStatusCode() == HttpStatus.TOO_MANY_REQUESTS.value()) {
+                HttpHeader retryAfterHeader = configurationRevision.getHeaders().get("retry-after-ms");
+
+                if (retryAfterHeader != null) {
+                    try {
+                        Integer retryAfter = Integer.valueOf(retryAfterHeader.getValue());
+
+                        Thread.sleep(retryAfter);
+                    } catch (NumberFormatException e) {
+                        LOGGER.warn("Unable to parse Retry After value.", e);
+                    } catch (InterruptedException e) {
+                        LOGGER.warn("Failed to wait after getting 429.", e);
+                    }
+                }
+
+                configurationRevision = null;
+            } else if (configurationRevision != null && configurationRevision.getItems().size() > 0) {
+                return configurationRevision.getItems().get(0);
+            } else {
+                return null;
+            }
+            retryCount++;
+        }
+        return null;
     }
 
     /**
-     * Gets a list of Configuration Settings from the given config store that match the
-     * Setting Selector criteria.
+     * Gets a list of Configuration Settings from the given config store that match the Setting Selector criteria.
      *
-     * @param settingSelector Information on which setting to pull. i.e. number of
-     * results, key value...
+     * @param settingSelector Information on which setting to pull. i.e. number of results, key value...
      * @param storeName Name of the App Configuration store to query against.
      * @return List of Configuration Settings.
      * @throws IOException thrown when failed to retrieve values.
      */
     public final List<ConfigurationSetting> listSettings(SettingSelector settingSelector, String storeName)
-            throws IOException {
+        throws IOException {
         ConfigurationAsyncClient client = buildClient(storeName);
 
         return client.listConfigurationSettings(settingSelector).collectList().block();
     }
 
     /**
-     * Composite watched key names separated by comma, the key names is made up of:
-     * prefix, context and key name pattern e.g., prefix: /config, context: /application,
-     * watched key: my.watch.key will return: /config/application/my.watch.key
+     * Composite watched key names separated by comma, the key names is made up of: prefix, context and key name pattern
+     * e.g., prefix: /config, context: /application, watched key: my.watch.key will return:
+     * /config/application/my.watch.key
      *
-     * The returned watched key will be one key pattern, one or multiple specific keys
-     * e.g., 1) * 2) /application/abc* 3) /application/abc 4) /application/abc,xyz
+     * The returned watched key will be one key pattern, one or multiple specific keys e.g., 1) * 2) /application/abc*
+     * 3) /application/abc 4) /application/abc,xyz
      *
      * @param store the {@code store} for which to composite watched key names
      * @param storeContextsMap map storing store name and List of context key-value pair