Github user markap14 commented on a diff in the pull request:
https://github.com/apache/nifi/pull/2130#discussion_r137852844
--- Diff:
nifi-nar-bundles/nifi-standard-services/nifi-lookup-services-bundle/nifi-lookup-services/src/main/java/org/apache/nifi/lookup/CSVRecordLookupService.java
---
@@ -0,0 +1,232 @@
+/*
+ * 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 org.apache.commons.csv.CSVFormat;
+import org.apache.commons.csv.CSVParser;
+import org.apache.commons.csv.CSVRecord;
+import org.apache.commons.lang3.StringUtils;
+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.controller.AbstractControllerService;
+import org.apache.nifi.controller.ConfigurationContext;
+import org.apache.nifi.controller.ControllerServiceInitializationContext;
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.processor.util.StandardValidators;
+import org.apache.nifi.reporting.InitializationException;
+import org.apache.nifi.serialization.SimpleRecordSchema;
+import org.apache.nifi.serialization.record.MapRecord;
+import org.apache.nifi.serialization.record.Record;
+import org.apache.nifi.serialization.record.RecordField;
+import org.apache.nifi.serialization.record.RecordFieldType;
+import org.apache.nifi.serialization.record.RecordSchema;
+import org.apache.nifi.util.file.monitor.LastModifiedMonitor;
+import org.apache.nifi.util.file.monitor.SynchronousFileWatcher;
+
+import java.io.FileNotFoundException;
+import java.io.FileReader;
+import java.io.IOException;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+@Tags({"lookup", "cache", "enrich", "join", "csv", "reloadable", "key",
"value", "record"})
+@CapabilityDescription("A reloadable CSV file-based lookup service. When
the lookup key is found in the CSV file, the remaining columns are returned as
a Record.")
+public class CSVRecordLookupService extends AbstractControllerService
implements RecordLookupService {
+
+ private static final String KEY = "key";
+
+ private static final Set<String> REQUIRED_KEYS =
Collections.unmodifiableSet(Stream.of(KEY).collect(Collectors.toSet()));
+
+ public static final PropertyDescriptor CSV_FILE =
+ new PropertyDescriptor.Builder()
+ .name("csv-file")
+ .displayName("CSV File")
+ .description("A CSV file.")
+ .required(true)
+ .addValidator(StandardValidators.FILE_EXISTS_VALIDATOR)
+ .expressionLanguageSupported(true)
+ .build();
+
+ static final PropertyDescriptor CSV_FORMAT = new
PropertyDescriptor.Builder()
+ .name("CSV Format")
+ .description("Specifies which \"format\" the CSV data is in,
or specifies if custom formatting should be used.")
+ .expressionLanguageSupported(false)
+
.allowableValues(Arrays.asList(CSVFormat.Predefined.values()).stream().map(e ->
e.toString()).collect(Collectors.toSet()))
+ .defaultValue(CSVFormat.Predefined.Default.toString())
+ .required(true)
+ .build();
+
+ public static final PropertyDescriptor LOOKUP_KEY_COLUMN =
+ new PropertyDescriptor.Builder()
+ .name("lookup-key-column")
+ .displayName("Lookup Key Column")
+ .description("Lookup key column.")
+ .required(true)
+ .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
+ .expressionLanguageSupported(true)
+ .build();
+
+ public static final PropertyDescriptor IGNORE_DUPLICATES =
+ new PropertyDescriptor.Builder()
+ .name("ignore-duplicates")
+ .displayName("Ignore Duplicates")
+ .description("Ignore duplicate keys for records in the
CSV file.")
+ .addValidator(StandardValidators.BOOLEAN_VALIDATOR)
+ .allowableValues("true", "false")
+ .defaultValue("true")
+ .required(true)
+ .build();
+
+ private List<PropertyDescriptor> properties;
+
+ private volatile ConcurrentMap<String, Map<String, Object>> cache;
+
+ private volatile String csvFile;
+
+ private volatile CSVFormat csvFormat;
+
+ private volatile String lookupKeyColumn;
+
+ private volatile boolean ignoreDuplicates;
+
+ private volatile SynchronousFileWatcher watcher;
+
+ private final ReentrantLock lock = new ReentrantLock();
+
+ private void loadCache() throws IllegalStateException, IOException {
+ if (lock.tryLock()) {
+ try {
+ final ComponentLog logger = getLogger();
+ if (logger.isDebugEnabled()) {
+ logger.debug("Loading lookup table from file: " +
csvFile);
+ }
+
+ final FileReader reader = new FileReader(csvFile);
+ final CSVParser records =
csvFormat.withFirstRecordAsHeader().parse(reader);
+ this.cache = new ConcurrentHashMap<>();
--- End diff --
I think we've got a threading bug here. As-is, if we have one thread
reloading the cache, another thread could be performing a lookup and access
this.cache when it has nothing in it, so it will get back an empty Optional
even if it should be returning a value. Instead, I think we need to create the
map as a local variable and only assign to this.cache once we've finished
populating the Map.
---
