Fetch configuration from CBS

- Fix memory leak.
- Add reactive configuration fetching from Consul. Now configuration is updated when any change in VES configuration has been done in Consul.

Change-Id: I9cd42e04844c9e99d4d03951185523b569dc9483
Issue-ID: DCAEGEN2-2495
Signed-off-by: Zebek Bogumil <bogumil.zebek@nokia.com>
(cherry picked from commit 1599617246f0ffec1b1c7840f9c7c42318183dcd)

1 files changed, 109 insertions, 0 deletions

diff --git a/src/main/java/org/onap/dcae/configuration/ConfigurationHandler.java b/src/main/java/org/onap/dcae/configuration/ConfigurationHandler.java
new file mode 100644
index 00000000..ebdf0474
--- /dev/null
+++ b/src/main/java/org/onap/dcae/configuration/ConfigurationHandler.java
@@ -0,0 +1,109 @@
+/*
+ * ============LICENSE_START=======================================================
+ * VES Collector
+ * ================================================================================
+ * Copyright (C) 2020 Nokia. All rights reserved.s
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+package org.onap.dcae.configuration;
+
+import com.google.gson.JsonObject;
+import io.vavr.control.Option;
+import org.json.JSONObject;
+import org.onap.dcae.configuration.cbs.CbsClientConfigurationProvider;
+import org.onap.dcaegen2.services.sdk.rest.services.cbs.client.api.CbsClient;
+import org.onap.dcaegen2.services.sdk.rest.services.cbs.client.api.CbsClientFactory;
+import org.onap.dcaegen2.services.sdk.rest.services.cbs.client.api.CbsRequests;
+import org.onap.dcaegen2.services.sdk.rest.services.cbs.client.model.CbsClientConfiguration;
+import org.onap.dcaegen2.services.sdk.rest.services.cbs.client.model.CbsRequest;
+import org.onap.dcaegen2.services.sdk.rest.services.model.logging.RequestDiagnosticContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import reactor.core.Disposable;
+import reactor.core.publisher.Mono;
+
+import java.time.Duration;
+
+/**
+ * ConfigurationHandler is responsible for receiving configuration updates from Consul.
+ * Any change made in the Consul will be reported as a notification.
+ */
+public class ConfigurationHandler {
+
+    private static Logger log = LoggerFactory.getLogger(ConfigurationHandler.class);
+    private static final String CONFIG_DICT = "config";
+
+    private final CbsClientConfigurationProvider cbsClientConfigurationProvider;
+    private final ConfigUpdater configUpdater;
+
+    /**
+     * Constructor
+     * @param cbsClientConfigurationProvider provides configuration to connect with Consul
+     * @param configUpdater for updating application configuration
+     */
+    public ConfigurationHandler(CbsClientConfigurationProvider cbsClientConfigurationProvider, ConfigUpdater configUpdater) {
+        this.cbsClientConfigurationProvider = cbsClientConfigurationProvider;
+        this.configUpdater = configUpdater;
+    }
+
+    /**
+     * Start listen for application configuration notifications with configuration changes
+     * @param interval defines period of time when notification can come
+     * @return {@link Disposable} handler to close Consul listener at the end
+     */
+    public Disposable startListen(Duration interval) {
+
+        log.info("Start listening for configuration from Consul ...");
+        log.info(String.format("Consul configuration will be fetched in %s period.", interval));
+
+        // Polling properties
+        final Duration initialDelay = Duration.ofSeconds(5);
+        final Duration period = interval;
+
+        final CbsRequest request = createCbsRequest();
+        final CbsClientConfiguration cbsClientConfiguration = cbsClientConfigurationProvider.get();
+
+        return createCbsClient(cbsClientConfiguration)
+                .flatMapMany(cbsClient -> cbsClient.updates(request, initialDelay, period))
+                .subscribe(
+                        this::handleConfigurationFromConsul,
+                        this::handleError
+                );
+    }
+
+    Mono<CbsClient> createCbsClient(CbsClientConfiguration cbsClientConfiguration) {
+        return CbsClientFactory.createCbsClient(cbsClientConfiguration);
+    }
+
+    void handleConfigurationFromConsul(JsonObject jsonObject) {
+        log.info("Configuration update from Consul {}", jsonObject);
+        if(jsonObject.has(CONFIG_DICT)) {
+            JsonObject config = jsonObject.getAsJsonObject(CONFIG_DICT);
+            JSONObject jObject = new JSONObject(config.toString());
+            configUpdater.updateConfig(Option.of(jObject));
+        } else {
+            throw new IllegalArgumentException(String.format("Invalid application configuration: %s ", jsonObject));
+        }
+    }
+
+    private void handleError(Throwable throwable) {
+        log.error("Unexpected error occurred during fetching configuration from Consul", throwable);
+    }
+
+    private CbsRequest createCbsRequest() {
+        RequestDiagnosticContext diagnosticContext = RequestDiagnosticContext.create();
+        return CbsRequests.getAll(diagnosticContext);
+    }
+}