[jira] [Updated] (NIFI-11971) FlowFile content is corrupted across the whole NiFi instance throughout ProcessSession::write with omitting writing any byte to OutputStream

["Serhii Nesterov (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/NIFI-11971?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Serhii Nesterov updated NIFI-11971:
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    Attachment: image-2023-08-20-19-31-16-598.png

> FlowFile content is corrupted across the whole NiFi instance throughout ProcessSession::write with omitting writing any byte to OutputStream
> --------------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: NIFI-11971
>                 URL: https://issues.apache.org/jira/browse/NIFI-11971
>             Project: Apache NiFi
>          Issue Type: Bug
>    Affects Versions: 1.23.0, 1.23.1
>            Reporter: Serhii Nesterov
>            Priority: Critical
>         Attachments: image-2023-08-20-19-31-16-598.png
>
>
> One of the scenarios for ProcessSession::write was broken after recent code refactoring within the following pull request: [https://github.com/apache/nifi/pull/7363/files]
> The issue is located in StandardContentClaimWriteCache.java in the write(final ContentClaim claim) method that returns an OutputStream used in the OutputStreamCallback interface to let NiFi processors write flowfile content through the ProcessSession::write method.
> If a processor calls session.write but does not write any data to the output stream, then none of the write methods in the OutputStream is invoked, hence the length of the content claim is not recomputed which means the length will have the default value that is equal to -1. Because of the latest refactoring changes that are based on creating a new content claim on each ProcessSession::write invocation the following formula gives the wrong result:
> previous offset + previous length = new offset.
> For example, if the previous offset was 1000 and nothing was written to the stream (length is -1), then 1000 + (-1) will give us 999 which means that the offset is shifted back by one, hence the next content will have an extra character from the previous content at the beginning and will lose the last character at the end, and all other FlowFiles anywhere in NiFi will be corrupted by this defect until the NiFi instance is restarted.
>  
> The following steps can be taken to reproduce the issue (critical in our commercial project):
>  * Create an empty text file (“a.txt”);
>  * Create a text file with any text (“b.txt”);
>  * Package these files into a .zip archive;
>  * Put it into a file system on Azure Cloud (we use ADLS Gen2);
>  * Read the zip file and unpack it content on the NiFi Canvas using FetchAzureDataLakeStorage and UnpackContent processors;
>  * Start a flow with the GenerateFlowFile processor. See the results. The empty file must be extracted before the non-empty file, otherwise the issue won’t reproduce. You’ll see that the second FlowFile content will be corrupted – the first character is an unreadable character from the zip archive (last character of the content with zip) fetched with FetchAzureDataLakeStorage and the last character will be lost. Starting from this point, NiFi cannot be used at all because any other processors will lead to FlowFile content corruption across the entire NiFi instance due to the shifted offset.
>  



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