[GitHub] ajschmidt commented on a change in pull request #2785: In Traffic Router Support Snapshots which only update Delivery Services

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ajschmidt commented on a change in pull request #2785: In Traffic Router Support Snapshots which only update Delivery Services
URL: https://github.com/apache/trafficcontrol/pull/2785#discussion_r239290158
 
 

 ##########
 File path: traffic_router/core/src/main/java/com/comcast/cdn/traffic_control/traffic_router/core/config/SnapshotEventsProcessor.java
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 @@ -0,0 +1,324 @@
+/*
+ *
+ * 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.
+ */
+
+package com.comcast.cdn.traffic_control.traffic_router.core.config;
+
+import com.comcast.cdn.traffic_control.traffic_router.core.cache.Cache;
+import com.comcast.cdn.traffic_control.traffic_router.core.cache.Cache.DeliveryServiceReference;
+import com.comcast.cdn.traffic_control.traffic_router.core.ds.DeliveryService;
+import com.comcast.cdn.traffic_control.traffic_router.core.util.JsonUtils;
+import com.comcast.cdn.traffic_control.traffic_router.core.util.JsonUtilsException;
+import com.fasterxml.jackson.databind.JsonNode;
+import org.apache.log4j.Logger;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.time.Instant;
+
+public class SnapshotEventsProcessor {
+	private static final Logger LOGGER = Logger.getLogger(SnapshotEventsProcessor.class);
+	final private Map<String, DeliveryService> creationEvents = new HashMap<>();
+	final private Map<String, DeliveryService> updateEvents = new HashMap<>();
+	final private Map<String, DeliveryService> deleteEvents = new HashMap<>();
+	final private Map<String, Cache> mappingEvents = new HashMap<>();
+	final private List<String> serverModEvents = new ArrayList<>();
+
+	public List<String> getDeleteCacheEvents() {
+		return deleteCacheEvents;
+	}
+
+	final private List<String> deleteCacheEvents = new ArrayList<>();
+	private JsonNode existingConfig = null;
+	private boolean loadall = false;
+
+	public static SnapshotEventsProcessor diffCrConfigs(final JsonNode newSnapDb,
+	                                                    final JsonNode existingDb) throws
+			JsonUtilsException, ParseException {
+		LOGGER.info("In diffCrConfigs");
+		final SnapshotEventsProcessor sepRet = new SnapshotEventsProcessor();
+
+		if (newSnapDb == null)
+		{
+			final String errstr = "Required parameter 'newSnapDb' was null";
+			LOGGER.error(errstr);
+			JsonUtils.throwException(errstr);
+		}
+		// Load the entire crConfig from the snapshot if there isn't one saved on the filesystem
+		if (existingDb == null || existingDb.size()< 1) {
+			sepRet.parseDeliveryServices(newSnapDb);
+			sepRet.loadall = true;
+			return sepRet;
+		}
+		// Load the entire crConfig from the snapshot if it is not version a version supporting
+		// DS Snapshots
+		if (!sepRet.versionSupportsDsSnapshots(newSnapDb)){
+			LOGGER.info("In diffCrConfig got old version of crConfig.");
+			sepRet.parseDeliveryServices(newSnapDb);
+			sepRet.loadall = true;
+			return sepRet;
+		}
+		// Load the entire crConfig from the snapshot if the load flag is set in the snapshot
+		final JsonNode config = JsonUtils.getJsonNode(newSnapDb, ConfigHandler.configKey);
+		if (Instant.parse(JsonUtils.optString(config, "modified", "1970-01-01T00:00:00Z")).isAfter(ConfigHandler.getLastSnapshotInstant())) {
+			sepRet.parseDeliveryServices(newSnapDb);
+			sepRet.loadall = true;
+			return sepRet;
+		}
+		// process only the changes to Delivery Services if none of the above conditions are met
+		sepRet.diffDeliveryServices(newSnapDb, existingDb);
+		sepRet.diffCacheMappings(newSnapDb, existingDb);
+		return sepRet;
+	}
+
+	private boolean versionSupportsDsSnapshots(final JsonNode snapDb) throws JsonUtilsException {
+		if (snapDb == null) {
+			return false;
+		}
+		return snapDb.has(ConfigHandler.versionKey);
+	}
+
+	private void diffCacheMappings(final JsonNode newSnapDb, final JsonNode existingDb) throws JsonUtilsException,
+			ParseException {
+		setExistingConfig(JsonUtils.getJsonNode(existingDb, ConfigHandler.configKey));
+		final JsonNode newServers = JsonUtils.getJsonNode(newSnapDb, ConfigHandler.contentServersKey);
+		final Iterator<String> newServersIter = newServers.fieldNames();
+		while (newServersIter.hasNext()) {
+			final String cid = newServersIter.next();
+			final JsonNode newCacheJo = newServers.get(cid);
+			if (!newCacheJo.has(ConfigHandler.deliveryServicesKey)) {
+				continue;
+			}
+			final Iterator<String> dsrKeys =
+					JsonUtils.getJsonNode(newCacheJo, ConfigHandler.deliveryServicesKey).fieldNames();
+			while (dsrKeys.hasNext()) {
+				final String dsrId = dsrKeys.next();
+				if (serverModEvents.contains(dsrId)) {
+					addMappingEvent(newCacheJo, cid);
+				}
+			}
+			if (dssLinkChangeDetected(cid, newCacheJo, existingDb)) {
+				addMappingEvent(newCacheJo, cid);
+			}
+		}
+
+		parseDeleteCacheEvents(JsonUtils.getJsonNode(existingDb, ConfigHandler.contentServersKey), newServers);
+	}
+
+	private boolean dssLinkChangeDetected(final String cid, final JsonNode newCacheJo, final JsonNode existingDb) throws
+			JsonUtilsException {
+		if (existingDb == null)
+		{
+			return true;
+		}
+		final JsonNode existingServers = JsonUtils.getJsonNode(existingDb,ConfigHandler.contentServersKey);
+		if (!existingServers.has(cid)) {
+		    return true;
+		}
+		final JsonNode existingCache = JsonUtils.getJsonNode(existingServers,cid);
+		if (newCacheJo.has(ConfigHandler.deliveryServicesKey) && !existingCache.has(ConfigHandler.deliveryServicesKey)) {
+			return true;
+		}
+		if (newCacheJo.has(ConfigHandler.deliveryServicesKey)) {
+			final JsonNode newDsLinks = JsonUtils.getJsonNode(newCacheJo, ConfigHandler.deliveryServicesKey);
+			return !newDsLinks.equals(JsonUtils.getJsonNode(existingCache, ConfigHandler.deliveryServicesKey));
+		} else {
+			return true;
+		}
+	}
+
+	private void addMappingEvent(final JsonNode newCacheJo, final String cid) throws JsonUtilsException, ParseException {
+		if (mappingEvents.keySet().contains(cid)) {
+			return;
+		}
+		final Cache modCache = new Cache(cid, cid, 1);
+		final List<DeliveryServiceReference> dsRefs = parseDsRefs(newCacheJo);
+		if (!dsRefs.isEmpty()) {
+			modCache.setDeliveryServices(dsRefs);
+		}
+		mappingEvents.put(cid, modCache);
+	}
+
+	private void parseDeleteCacheEvents(final JsonNode exCacheServers, final JsonNode newServers) {
+		final Iterator<String> exServersIter = exCacheServers.fieldNames();
+		exServersIter.forEachRemaining(cId->{
 
 Review comment:
   In most cases there are calls within the 'while' code block which throw exceptions. When you switch the code to a closure the exceptions get trapped inside it. The only way to handle it is to add a try/catch block inside the closure and add the exception to a 'final' container you defined outside the closure and then throw the exception once you have returned from the closure. Very messy.  

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