Github user pvillard31 commented on a diff in the pull request:
https://github.com/apache/nifi/pull/1328#discussion_r95008090
--- Diff:
nifi-nar-bundles/nifi-stateful-analysis-bundle/nifi-stateful-analysis-processors/src/main/java/org/apache/nifi/processors/stateful/analysis/AttributeRollingWindow.java
---
@@ -0,0 +1,325 @@
+/*
+ * 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.processors.stateful.analysis;
+
+import org.apache.nifi.annotation.behavior.InputRequirement;
+import org.apache.nifi.annotation.behavior.Stateful;
+import org.apache.nifi.annotation.behavior.TriggerSerially;
+import org.apache.nifi.annotation.behavior.WritesAttribute;
+import org.apache.nifi.annotation.behavior.WritesAttributes;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.annotation.lifecycle.OnScheduled;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.state.Scope;
+import org.apache.nifi.components.state.StateManager;
+import org.apache.nifi.components.state.StateMap;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+import org.apache.nifi.processor.util.StandardValidators;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+
+import static
org.apache.nifi.processors.stateful.analysis.AttributeRollingWindow.ROLLING_WINDOW_COUNT_KEY;
+import static
org.apache.nifi.processors.stateful.analysis.AttributeRollingWindow.ROLLING_WINDOW_VALUE_KEY;
+
+@TriggerSerially
+@InputRequirement(InputRequirement.Requirement.INPUT_REQUIRED)
+@Tags({"Attribute Expression Language", "state", "data science",
"rolling", "window"})
+@CapabilityDescription("Track a Rolling Window based on evaluating an
Expression Language expression on each FlowFile and add that value to the
processor's state. Each FlowFile will be emitted " +
+ "with the count of FlowFiles and total aggregate value of values
processed in the current time window.")
+@WritesAttributes({
+ @WritesAttribute(attribute = ROLLING_WINDOW_VALUE_KEY, description
= "The rolling window value (sum of all the values stored)."),
+ @WritesAttribute(attribute = ROLLING_WINDOW_COUNT_KEY, description
= "The count of the number of FlowFiles seen in the rolling window.")
+})
+@Stateful(scopes = {Scope.LOCAL}, description = "Store the values backing
the rolling window. This includes storing the individual values and their
time-stamps or the batches of values and their " +
+ "counts.")
+public class AttributeRollingWindow extends AbstractProcessor {
+
+ public static final String COUNT_KEY = "count";
+ public static final String ROLLING_WINDOW_VALUE_KEY =
"rolling_window_value";
+ public static final String ROLLING_WINDOW_COUNT_KEY =
"rolling_window_count";
+
+ public static final String CURRENT_MICRO_BATCH_STATE_TS_KEY =
"start_curr_batch_ts";
+ public static final String BATCH_APPEND_KEY = "_batch";
+ public static final String COUNT_APPEND_KEY = "_count";
+ public static final int COUNT_APPEND_KEY_LENGTH = 6;
+
+ static final PropertyDescriptor VALUE_TO_TRACK = new
PropertyDescriptor.Builder()
+ .name("Value to track")
+ .description("The expression on which to evaluate each
FlowFile. The result of the expression will be added to the rolling window
value.")
+ .expressionLanguageSupported(true)
+
.addValidator(StandardValidators.ATTRIBUTE_EXPRESSION_LANGUAGE_VALIDATOR)
+ .required(true)
+ .build();
+ static final PropertyDescriptor TIME_WINDOW = new
PropertyDescriptor.Builder()
+ .name("Time window")
+ .description("The time window on which to calculate the
rolling window.")
+ .addValidator(StandardValidators.TIME_PERIOD_VALIDATOR)
+ .required(true)
+ .build();
+ static final PropertyDescriptor SUB_WINDOW_LENGTH = new
PropertyDescriptor.Builder()
+ .name("Sub-window Length")
+ .description("When set, values will be batched into
sub-windows of the set length. This allows for much larger length total windows
to be set but sacrifices some precision. If this is " +
+ "not set (or is 0) then each value is stored in state
with the timestamp of when it was received. After the length of time stated in
" + TIME_WINDOW.getDisplayName() +
+ " elaspes the value will be removed. If this is set,
values will be batched together every X amount of time (where X is the time
period set for this property) and removed " +
+ "all at once.")
+ .addValidator(StandardValidators.TIME_PERIOD_VALIDATOR)
+ .required(false)
+ .build();
+
+
+ private final Set<Relationship> relationships;
+ private final List<PropertyDescriptor> properties;
+ private Long timeWindow;
+ private Long microBatchTime;
+ private static final Scope SCOPE = Scope.LOCAL;
+
+ // relationships
+ public static final Relationship REL_SUCCESS = new
Relationship.Builder()
+ .description("All FlowFiles are successfully processed are
routed here")
+ .name("success")
+ .build();
+ public static final Relationship REL_FAILURE = new
Relationship.Builder()
+ .name("set state fail")
+ .description("When state fails to save when processing a
certain FlowFile it is routed here.")
+ .build();
+
+ {
+ final Set<Relationship> relationshipSet = new HashSet<>();
+ relationshipSet.add(REL_SUCCESS);
+ relationshipSet.add(REL_FAILURE);
+ relationships = Collections.unmodifiableSet(relationshipSet);
+
+ final List<PropertyDescriptor> properties = new ArrayList<>();
+ properties.add(VALUE_TO_TRACK);
+ properties.add(TIME_WINDOW);
+ properties.add(SUB_WINDOW_LENGTH);
+ this.properties = Collections.unmodifiableList(properties);
+ }
+
+ @Override
+ public Set<Relationship> getRelationships() {
+ return relationships;
+ }
+
+ @Override
+ protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
+ return properties;
+ }
+
+ @OnScheduled
+ public void onScheduled(final ProcessContext context) throws
IOException {
+ timeWindow =
context.getProperty(TIME_WINDOW).asTimePeriod(TimeUnit.MILLISECONDS);
+ microBatchTime =
context.getProperty(SUB_WINDOW_LENGTH).asTimePeriod(TimeUnit.MILLISECONDS);
+
+ if(microBatchTime == null || microBatchTime == 0) {
+ StateManager stateManager = context.getStateManager();
+ StateMap state = stateManager.getState(SCOPE);
+ HashMap<String, String> tempMap = new HashMap<>();
+ tempMap.putAll(state.toMap());
+ if (!tempMap.containsKey(COUNT_KEY)) {
+ tempMap.put(COUNT_KEY, "0");
+ context.getStateManager().setState(tempMap, SCOPE);
+ }
+ }
+ }
+
+ @Override
+ public void onTrigger(ProcessContext context, ProcessSession session)
throws ProcessException {
+ FlowFile flowFile = session.get();
+ if (flowFile == null) {
+ return;
+ }
+
+ try {
+ Long currTime = System.currentTimeMillis();
+ if(microBatchTime == null){
+ noMicroBatch(context, session, flowFile, currTime);
+ } else{
+ microBatch(context, session, flowFile, currTime);
+ }
+
+ } catch (IOException e) {
+ getLogger().error("Failed to save the state for {} due to {}",
new Object[] { flowFile, e});
+ session.transfer(flowFile, REL_FAILURE);
+ }
+ }
+
+ private void noMicroBatch(ProcessContext context, ProcessSession
session, FlowFile flowFile, Long currTime) throws IOException {
+ final StateManager stateManager = context.getStateManager();
+
+ Map<String, String> state = new
HashMap<>(stateManager.getState(SCOPE).toMap());
+ Long count = Long.valueOf(state.get(COUNT_KEY));
+ count ++;
+
+ Set<String> keysToRemove = new HashSet<>();
+
+ for(String key: state.keySet()){
+ if(!key.equals(COUNT_KEY)){
+ Long timeStamp = Long.decode(key);
+
+ if(currTime - timeStamp > timeWindow) {
+ keysToRemove.add(key);
+ count --;
+
+ }
+ }
+ }
+ String countString = String.valueOf(count);
+
+ for(String key: keysToRemove){
+ state.remove(key);
+ }
+
+ Double aggregateValue = 0.0D;
+
+ for(Map.Entry<String,String> entry: state.entrySet()){
+ if(!entry.getKey().equals(COUNT_KEY)){
+ aggregateValue += Double.valueOf(entry.getValue());
+ }
+ }
+
+
+ final Double currentFlowFileValue =
context.getProperty(VALUE_TO_TRACK).evaluateAttributeExpressions(flowFile).asDouble();
--- End diff --
In case of NumberFormatException, I think that the flow file should be sent
to a specific relationship, otherwise it will remain in the input relationship.
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