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https://issues.apache.org/jira/browse/NIFI-4982?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16433987#comment-16433987
]
ASF GitHub Bot commented on NIFI-4982:
--------------------------------------
Github user mattyb149 commented on a diff in the pull request:
https://github.com/apache/nifi/pull/2558#discussion_r180771987
--- Diff:
nifi-nar-bundles/nifi-standard-services/nifi-lookup-services-bundle/nifi-lookup-services/src/main/java/org/apache/nifi/lookup/DistributedMapCacheLookupService.java
---
@@ -0,0 +1,127 @@
+/*
+ * 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.lookup;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.annotation.lifecycle.OnEnabled;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.Validator;
+import org.apache.nifi.controller.AbstractControllerService;
+import org.apache.nifi.controller.ConfigurationContext;
+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.distributed.cache.client.exception.DeserializationException;
+import
org.apache.nifi.distributed.cache.client.exception.SerializationException;
+
+@Tags({"lookup", "enrich", "key", "value", "map", "cache", "distributed"})
+@CapabilityDescription("Allows to choose a distributed map cache client to
retrieve the value associated to a key. "
+ + "The coordinates that are passed to the lookup must contain the key
'key'.")
+public class DistributedMapCacheLookupService extends
AbstractControllerService implements StringLookupService {
+ private static final String KEY = "key";
+ private static final Set<String> REQUIRED_KEYS =
Stream.of(KEY).collect(Collectors.toSet());
+
+ private volatile DistributedMapCacheClient cache;
+ private final Serializer<String> keySerializer = new
StringSerializer();
+ private final Deserializer<String> valueDeserializer = new
StringDeserializer();
+
+ public static final PropertyDescriptor PROP_DISTRIBUTED_CACHE_SERVICE
= new PropertyDescriptor.Builder()
+ .name("distributed-map-cache-service")
+ .displayName("Distributed Cache Service")
+ .description("The Controller Service that is used to get the
cached values.")
+ .required(true)
+ .identifiesControllerService(DistributedMapCacheClient.class)
+ .build();
+
+ @Override
+ protected PropertyDescriptor
getSupportedDynamicPropertyDescriptor(final String propertyDescriptorName) {
+ return new PropertyDescriptor.Builder()
+ .name(propertyDescriptorName)
+ .required(false)
+ .dynamic(true)
+ .addValidator(Validator.VALID)
+ .expressionLanguageSupported(true)
+ .build();
+ }
+
+ @OnEnabled
+ public void cacheConfiguredValues(final ConfigurationContext context) {
+ cache =
context.getProperty(PROP_DISTRIBUTED_CACHE_SERVICE).asControllerService(DistributedMapCacheClient.class);
+ }
+
+ @Override
+ protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
+ final List<PropertyDescriptor> descriptors = new ArrayList<>();
+ descriptors.add(PROP_DISTRIBUTED_CACHE_SERVICE);
+ return descriptors;
+ }
+
+ @Override
+ public Optional<String> lookup(final Map<String, Object> coordinates) {
+ if (coordinates == null) {
+ return Optional.empty();
+ }
+
+ final String key = coordinates.get(KEY).toString();
+ if (key == null) {
+ return Optional.empty();
+ }
+
+ try {
+ return Optional.ofNullable(cache.get(key, keySerializer,
valueDeserializer));
+ } catch (IOException e) {
+ getLogger().error("Error while trying to get the value from
distributed map cache with key = " + key, e);
+ return Optional.empty();
+ }
+ }
+
+ @Override
+ public Set<String> getRequiredKeys() {
+ return REQUIRED_KEYS;
+ }
+
+ public static class StringDeserializer implements Deserializer<String>
{
--- End diff --
Should these be moved up to a utilities class or API package? Also, do we
support character sets other than UTF-8?
> Add a DistributedMapCacheLookupService
> --------------------------------------
>
> Key: NIFI-4982
> URL: https://issues.apache.org/jira/browse/NIFI-4982
> Project: Apache NiFi
> Issue Type: New Feature
> Components: Extensions
> Reporter: Pierre Villard
> Assignee: Pierre Villard
> Priority: Major
> Attachments: distributedMapCacheLookup.xml
>
>
> Add a new lookup controller service that takes a Distributed Map Cache client
> to lookup for values based on a key. This allows users to leverage the
> internal Disitributed Map Cache server and/or the Redis to perform lookup
> access (with LookupRecord processor for instance).
> Attached is a template to test the PR.
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