[ 
https://issues.apache.org/jira/browse/NIFI-3792?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16655412#comment-16655412
 ] 

ASF GitHub Bot commented on NIFI-3792:
--------------------------------------

Github user patricker commented on a diff in the pull request:

    https://github.com/apache/nifi/pull/3090#discussion_r226343311
  
    --- Diff: 
nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/RetryCount.java
 ---
    @@ -0,0 +1,210 @@
    +/*
    + * 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.standard;
    +
    +import org.apache.nifi.annotation.behavior.InputRequirement;
    +import org.apache.nifi.annotation.behavior.ReadsAttribute;
    +import org.apache.nifi.annotation.behavior.SideEffectFree;
    +import org.apache.nifi.annotation.behavior.SupportsBatching;
    +import org.apache.nifi.annotation.behavior.WritesAttribute;
    +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.flowfile.FlowFile;
    +import org.apache.nifi.processor.AbstractProcessor;
    +import org.apache.nifi.processor.DataUnit;
    +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.util.ArrayList;
    +import java.util.Collections;
    +import java.util.HashSet;
    +import java.util.List;
    +import java.util.Optional;
    +import java.util.Set;
    +
    +import static 
org.apache.nifi.processors.standard.RetryCount.RETRY_COUNT_ATTRIBUTE_KEY;
    +import static 
org.apache.nifi.annotation.behavior.InputRequirement.Requirement.INPUT_REQUIRED;
    +import static 
org.apache.nifi.expression.ExpressionLanguageScope.VARIABLE_REGISTRY;
    +
    +/**
    + * Created by jpercivall on 3/17/17.
    + */
    +@SupportsBatching
    +@SideEffectFree
    +@InputRequirement(INPUT_REQUIRED)
    +@Tags({"penalize", "retry", "penalize"})
    +@CapabilityDescription("Used to facilitate retrying a FlowFile a set 
number of times before considering the FlowFile 'failed'. Can also be used as a 
utility to penalize FlowFiles.")
    +@WritesAttribute(attribute = RETRY_COUNT_ATTRIBUTE_KEY, description = "The 
number of times this FlowFile has been routed to 'Retry'.")
    +@ReadsAttribute(attribute = RETRY_COUNT_ATTRIBUTE_KEY, description = "The 
number of times this FlowFile has been routed to 'Retry'.")
    +public class RetryCount extends AbstractProcessor {
    +
    +    public static final String RETRY_COUNT_ATTRIBUTE_KEY = 
"retryCountProcessor.timesRetried";
    +
    +    public static final PropertyDescriptor PROP_RETRY_LIMIT = new 
PropertyDescriptor.Builder()
    +            .name("Retry limit")
    +            .displayName("Retry limit")
    +            .description("The number of times to retry the FlowFile before 
considering it 'failed' and routing it to 'over limit'.")
    +            .expressionLanguageSupported(VARIABLE_REGISTRY)
    +            .required(true)
    +            .addValidator(StandardValidators.INTEGER_VALIDATOR)
    +            .defaultValue("3")
    +            .build();
    +
    +    public static final PropertyDescriptor PROP_PENALIZE_FLOWFILE = new 
PropertyDescriptor.Builder()
    +            .name("Penalize FlowFile")
    +            .displayName("Penalize FlowFile")
    +            .description("If true then the FlowFiles routed to 'retry' 
will be penalized.")
    +            .allowableValues("true", "false")
    +            .defaultValue("true")
    +            .build();
    +
    +    public static final PropertyDescriptor PROP_WARN_ON_OVER_LIMIT = new 
PropertyDescriptor.Builder()
    +            .name("Warn on 'over limit'")
    +            .displayName("Warn on 'over limit'")
    +            .description("If true then when a FlowFile is routed to 'over 
limit' a message will be logged at the level 'warn'.")
    +            .allowableValues("true", "false")
    +            .defaultValue("true")
    +            .build();
    +
    +    public static final PropertyDescriptor 
PROP_INPUT_QUEUE_DATA_SIZE_LIMIT = new PropertyDescriptor.Builder()
    +            .name("Input queue data size limit")
    +            .displayName("Input queue data size limit")
    +            .description("If the total input queue data size (a 
combination of all connections feeding this processor) is above this configured 
limit then any processed FlowFile is routed to " +
    +                    "'over limit'. This is necessary to avoid a 
back-pressure deadlock caused by with circular back-pressure. The default 
values are set to be half of what the default " +
    +                    "configuration values are for connections 
back-pressure.")
    +            .addValidator(StandardValidators.DATA_SIZE_VALIDATOR)
    +            .expressionLanguageSupported(VARIABLE_REGISTRY)
    +            .defaultValue("500 mb")
    +            .build();
    +
    +    public static final PropertyDescriptor PROP_INPUT_QUEUE_COUNT_LIMIT = 
new PropertyDescriptor.Builder()
    +            .name("Input queue count limit")
    +            .displayName("Input queue count limit")
    +            .description("If the total input queue FlowFile count (a 
combination of all connections feeding this processor) is above this configured 
limit then any processed FlowFile is routed to " +
    +                    "'over limit'. This is necessary to avoid a 
back-pressure deadlock caused by with circular back-pressure. The default 
values are set to be half of what the default " +
    +                    "configuration values are for connections 
back-pressure.")
    +            .addValidator(StandardValidators.POSITIVE_INTEGER_VALIDATOR)
    +            .expressionLanguageSupported(VARIABLE_REGISTRY)
    +            .defaultValue("5000")
    --- End diff --
    
    Same feedback for count limit as for size limit.


> A processor to facilitate retrying FlowFiles
> --------------------------------------------
>
>                 Key: NIFI-3792
>                 URL: https://issues.apache.org/jira/browse/NIFI-3792
>             Project: Apache NiFi
>          Issue Type: New Feature
>            Reporter: Joseph Percivall
>            Assignee: Joseph Percivall
>            Priority: Major
>
> When dealing with processor failures in production, potentially related to 
> network issues, the current best practice is to retry the flowfile a couple 
> times before declaring it a failure[1]. This currently requires multiple 
> processors and penalizing the flowfile isn't possible. Also if the flow is 
> not fast enough, back-pressure can cause a livelocked state which requires 
> manual intervention.
> A new processor should be added to not only encourage best practices but also 
> offer configuration options to deal with un-optimal situations.
> [1] 
> https://community.hortonworks.com/questions/77336/nifi-best-practices-for-error-handling.html



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