Github user markap14 commented on a diff in the pull request:
https://github.com/apache/nifi/pull/2876#discussion_r202719634
--- Diff:
nifi-nar-bundles/nifi-extension-utils/nifi-processor-utils/src/main/java/org/apache/nifi/processor/util/list/ListedEntityTracker.java
---
@@ -0,0 +1,322 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.nifi.processor.util.list;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.apache.nifi.components.AllowableValue;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.ValidationContext;
+import org.apache.nifi.components.ValidationResult;
+import org.apache.nifi.components.state.Scope;
+import org.apache.nifi.distributed.cache.client.Deserializer;
+import org.apache.nifi.distributed.cache.client.DistributedMapCacheClient;
+import org.apache.nifi.distributed.cache.client.Serializer;
+import org.apache.nifi.expression.ExpressionLanguageScope;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.exception.ProcessException;
+import org.apache.nifi.processor.util.StandardValidators;
+import org.apache.nifi.util.StringUtils;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.Supplier;
+import java.util.stream.Collectors;
+import java.util.zip.GZIPInputStream;
+import java.util.zip.GZIPOutputStream;
+
+import static java.lang.String.format;
+import static
org.apache.nifi.processor.util.list.AbstractListProcessor.REL_SUCCESS;
+
+public class ListedEntityTracker<T extends ListableEntity> {
+
+ private ObjectMapper objectMapper = new ObjectMapper();
+ private volatile Map<String, ListedEntity> alreadyListedEntities;
+
+ private static final String NOTE = "Used by 'Tracking Entities'
strategy.";
+ public static final PropertyDescriptor TRACKING_STATE_CACHE = new
PropertyDescriptor.Builder()
+ .name("et-state-cache")
+ .displayName("Entity Tracking State Cache")
+ .description(format("Listed entities are stored in the
specified cache storage" +
+ " so that this processor can resume listing across
NiFi restart or in case of primary node change." +
+ " 'Tracking Entities' strategy require tracking
information of all listed entities within the last 'Tracking Time Window'." +
+ " To support large number of entities, the strategy
uses DistributedMapCache instead of managed state." +
+ " Cache key format is
'ListedEntityTracker::{processorId}(::{nodeId})'." +
+ " If it tracks per node listed entities, then the
optional '::{nodeId}' part is added to manage state separately." +
+ " E.g. cluster wide cache key =
'ListedEntityTracker::8dda2321-0164-1000-50fa-3042fe7d6a7b'," +
+ " per node cache key =
'ListedEntityTracker::8dda2321-0164-1000-50fa-3042fe7d6a7b::nifi-node3'" +
+ " The stored cache content is Gzipped JSON string." +
+ " The cache key will be deleted when target listing
configuration is changed." +
+ " %s", NOTE))
+ .identifiesControllerService(DistributedMapCacheClient.class)
+ .build();
+
+ public static final PropertyDescriptor TRACKING_TIME_WINDOW = new
PropertyDescriptor.Builder()
+ .name("et-time-window")
+ .displayName("Entity Tracking Time Window")
+ .description(format("Specify how long this processor should
track already-listed entities." +
+ " 'Tracking Entities' strategy can pick any entity
whose timestamp is inside the specified time window." +
+ " For example, if set to '30 minutes', any entity
having timestamp in recent 30 minutes will be the listing target when this
processor runs." +
+ " A listed entity is considered 'new/updated' and a
FlowFile is emitted if one of following condition meets:" +
+ " 1. does not exist in the already-listed entities," +
+ " 2. has newer timestamp than the cached entity," +
+ " 3. has different size than the cached entity." +
+ " If a cached entity's timestamp becomes older than
specified time window, that entity will be removed from the cached
already-listed entities." +
+ " %s", NOTE))
+ .addValidator(StandardValidators.TIME_PERIOD_VALIDATOR)
+
.expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
+ .defaultValue("3 hours")
+ .build();
+
+ private static final AllowableValue INITIAL_LISTING_TARGET_ALL = new
AllowableValue("all", "All Available",
+ "Regardless of entities timestamp, all existing entities will
be listed at the initial listing activity.");
+ private static final AllowableValue INITIAL_LISTING_TARGET_WINDOW =
new AllowableValue("window", "Tracking Time Window",
+ "Ignore entities having timestamp older than the specified
'Tracking Time Window' at the initial listing activity.");
+
+ public static final PropertyDescriptor INITIAL_LISTING_TARGET = new
PropertyDescriptor.Builder()
+ .name("et-initial-listing-target")
+ .displayName("Entity Tracking Initial Listing Target")
+ .description(format("Specify how initial listing should be
handled." +
+ " %s", NOTE))
+ .allowableValues(INITIAL_LISTING_TARGET_WINDOW,
INITIAL_LISTING_TARGET_ALL)
+ .defaultValue(INITIAL_LISTING_TARGET_WINDOW.getValue())
+ .build();
+
+ public static final PropertyDescriptor NODE_IDENTIFIER = new
PropertyDescriptor.Builder()
+ .name("et-node-identifier")
+ .displayName("Entity Tracking Node Identifier")
+ .description(format("The configured value will be appended to
the cache key" +
+ " so that listing state can be tracked per NiFi node
rather than cluster wide" +
+ " when tracking state is scoped to LOCAL. %s", NOTE))
+ .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
+
.expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
+ .defaultValue("${hostname()}")
+ .build();
+
+ private static Supplier<Long> CURRENT_TIMESTAMP =
System::currentTimeMillis;
+
+ private Serializer<String> stringSerializer = (v, o) ->
o.write(v.getBytes(StandardCharsets.UTF_8));
+ private Serializer<Map<String, ListedEntity>> listedEntitiesSerializer
+ = (v, o) -> objectMapper.writeValue(new GZIPOutputStream(o),
v);
+ private Deserializer<Map<String, ListedEntity>>
listedEntitiesDeserializer
+ = v -> (v == null || v.length == 0) ? null
+ : objectMapper.readValue(new GZIPInputStream(new
ByteArrayInputStream(v)), new TypeReference<Map<String, ListedEntity>>() {});
+
+ private final String componentId;
+ private final ComponentLog logger;
+ private final Scope scope;
+
+ /*
+ * The nodeId and mapCacheClient being used at the previous
trackEntities method execution is captured,
+ * so that it can be used when resetListedEntities is called.
+ */
+ private String nodeId;
+ private DistributedMapCacheClient mapCacheClient;
+
+ ListedEntityTracker(String componentId, ComponentLog logger, Scope
scope) {
+ this.componentId = componentId;
+ this.logger = logger;
+ this.scope = scope;
+ }
+
+ static void validateProperties(ValidationContext context,
Collection<ValidationResult> results, Scope scope) {
+ final Consumer<PropertyDescriptor> validateRequiredProperty =
property -> {
+ if (!context.getProperty(property).isSet()) {
+ final String displayName = property.getDisplayName();
+ results.add(new ValidationResult.Builder()
+ .subject(displayName)
+ .explanation(format("'%s' is required to use '%s'
listing strategy", displayName,
AbstractListProcessor.BY_ENTITIES.getDisplayName()))
+ .valid(false)
+ .build());
+ }
+ };
+
validateRequiredProperty.accept(ListedEntityTracker.TRACKING_STATE_CACHE);
+
validateRequiredProperty.accept(ListedEntityTracker.TRACKING_TIME_WINDOW);
+
+ if (Scope.LOCAL.equals(scope)) {
+ if
(StringUtils.isEmpty(context.getProperty(NODE_IDENTIFIER).evaluateAttributeExpressions().getValue()))
{
+ results.add(new ValidationResult.Builder()
+ .subject(NODE_IDENTIFIER.getDisplayName())
+ .explanation(format("'%s' is required to use local
scope with '%s' listing strategy",
+ NODE_IDENTIFIER.getDisplayName(),
AbstractListProcessor.BY_ENTITIES.getDisplayName()))
+ .build());
+ }
+ }
+ }
+
+ static void setCurrentTimestampSupplier(Supplier<Long> supplier) {
+ CURRENT_TIMESTAMP = supplier;
+ }
+
+ private String getCacheKey() {
+ switch (scope) {
+ case LOCAL:
+ return format("%s::%s::%s", getClass().getSimpleName(),
componentId, nodeId);
+ case CLUSTER:
+ return format("%s::%s", getClass().getSimpleName(),
componentId);
+ }
+ throw new IllegalArgumentException("Unknown scope: " + scope);
+ }
+
+ private void persistListedEntities(Map<String, ListedEntity>
listedEntities) throws IOException {
+ final String cacheKey = getCacheKey();
+ logger.debug("Persisting listed entities: {}={}", new
Object[]{cacheKey, listedEntities});
+ mapCacheClient.put(cacheKey, listedEntities, stringSerializer,
listedEntitiesSerializer);
+ }
+
+ private Map<String, ListedEntity> fetchListedEntities() throws
IOException {
+ final String cacheKey = getCacheKey();
+ final Map<String, ListedEntity> listedEntities =
mapCacheClient.get(cacheKey, stringSerializer, listedEntitiesDeserializer);
+ logger.debug("Fetched listed entities: {}={}", new
Object[]{cacheKey, listedEntities});
+ return listedEntities;
+ }
+
+ void clearListedEntities() throws IOException {
+ alreadyListedEntities = null;
+ if (mapCacheClient != null) {
+ final String cacheKey = getCacheKey();
+ logger.debug("Removing listed entities from cache storage:
{}", new Object[]{cacheKey});
+ mapCacheClient.remove(cacheKey, stringSerializer);
+ }
+ }
+
+ public void trackEntities(ProcessContext context, ProcessSession
session,
+ boolean justElectedPrimaryNode,
+ Function<Long, Collection<T>> listEntities,
+ Function<T, Map<String, String>>
createAttributes) throws ProcessException {
+
+ boolean initialListing = false;
+ mapCacheClient =
context.getProperty(TRACKING_STATE_CACHE).asControllerService(DistributedMapCacheClient.class);
+ if (Scope.LOCAL.equals(scope)) {
+ nodeId =
context.getProperty(ListedEntityTracker.NODE_IDENTIFIER).evaluateAttributeExpressions().getValue();
+ }
+
+ if (alreadyListedEntities == null || justElectedPrimaryNode) {
+ logger.info(justElectedPrimaryNode
+ ? "Just elected as Primary node, restoring
already-listed entities."
+ : "At the first onTrigger, restoring already-listed
entities.");
+ try {
+ alreadyListedEntities = fetchListedEntities();
+ if (alreadyListedEntities == null) {
+ alreadyListedEntities = new HashMap<>();
+ initialListing = true;
+ }
+ } catch (IOException e) {
+ throw new ProcessException("Failed to restore
already-listed entities due to " + e, e);
+ }
+ }
+
+ final long currentTimeMillis = CURRENT_TIMESTAMP.get();
+ final long watchWindowMillis =
context.getProperty(TRACKING_TIME_WINDOW).evaluateAttributeExpressions().asTimePeriod(TimeUnit.MILLISECONDS);
+
+ final String initialListingTarget =
context.getProperty(INITIAL_LISTING_TARGET).getValue();
+ final long minTimestampToList = (initialListing &&
INITIAL_LISTING_TARGET_ALL.getValue().equals(initialListingTarget))
+ ? -1 : currentTimeMillis - watchWindowMillis;
+
+ final Collection<T> listedEntities =
listEntities.apply(minTimestampToList);
+
+ if (listedEntities.size() == 0) {
+ logger.debug("No entity is listed. Yielding.");
+ context.yield();
+ return;
+ }
+
+ final List<T> updatedEntities =
listedEntities.stream().filter(entity -> {
+ final String identifier = entity.getIdentifier();
+
+ if (entity.getTimestamp() < minTimestampToList) {
+ logger.trace("Skipped {} having older timestamp than the
minTimestampToList {}.", new Object[]{identifier, entity.getTimestamp(),
minTimestampToList});
+ return false;
+ }
+
+ final ListedEntity alreadyListedEntity =
alreadyListedEntities.get(identifier);
+ if (alreadyListedEntity == null) {
+ logger.trace("Picked {} being newly found.", new
Object[]{identifier});
+ return true;
+ }
+
+ if (entity.getTimestamp() >
alreadyListedEntity.getTimestamp()) {
+ logger.trace("Picked {} having newer timestamp {} than
{}.",
+ new Object[]{identifier, entity.getTimestamp(),
alreadyListedEntity.getTimestamp()});
+ return true;
+ }
+
+ if (entity.getSize() != alreadyListedEntity.getSize()) {
+ logger.trace("Picked {} having different size {} than {}.",
+ new Object[]{identifier, entity.getSize(),
alreadyListedEntity.getSize()});
+ return true;
+ }
+
+ logger.trace("Skipped {}, not changed.", new
Object[]{identifier, entity.getTimestamp(), minTimestampToList});
+ return false;
+ }).collect(Collectors.toList());
+
+ // Find old enough entries.
+ final List<String> oldEntityIds =
alreadyListedEntities.entrySet().stream()
+ .filter(entry -> entry.getValue().getTimestamp() <
minTimestampToList).map(Map.Entry::getKey)
+ .collect(Collectors.toList());
+
+ if (updatedEntities.isEmpty() && oldEntityIds.isEmpty()) {
+ logger.debug("None of updated or old entity was found.
Yielding.");
+ context.yield();
+ return;
+ }
+
+ // Remove old entries.
+ oldEntityIds.forEach(oldEntityId ->
alreadyListedEntities.remove(oldEntityId));
+
+ // Emit updated entities.
+ updatedEntities.forEach(updatedEntity -> {
+ FlowFile flowFile = session.create();
+ flowFile = session.putAllAttributes(flowFile,
createAttributes.apply(updatedEntity));
+ session.transfer(flowFile, REL_SUCCESS);
+ // In order to reduce object size, discard meta data captured
at the sub-classes.
+ final ListedEntity listedEntity = new ListedEntity();
+ listedEntity.setTimestamp(updatedEntity.getTimestamp());
+ listedEntity.setSize(updatedEntity.getSize());
+ alreadyListedEntities.put(updatedEntity.getIdentifier(),
listedEntity);
+ });
+
+ // Commit ProcessSession before persisting listed entities.
+ // In case persisting listed entities failure, same entities may
be listed again, but better than not listing.
+ session.commit();
+ try {
+ logger.debug("Removed old entities count: {}, Updated entities
count: {}",
+ new Object[]{oldEntityIds.size(),
updatedEntities.size()});
+ if (logger.isTraceEnabled()) {
+ logger.trace("\"Removed old entities: {}, Updated
entities: {}",
--- End diff --
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