[jira] [Updated] (FLUME-3352) Unnecessary canary test will block on readonly spooldir while another trackerdir is set.

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

     [ https://issues.apache.org/jira/browse/FLUME-3352?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

taoyang updated FLUME-3352:
---------------------------
    Attachment: FLUME-3352-0.patch

> Unnecessary canary test will block on readonly spooldir while another trackerdir is set.
> ----------------------------------------------------------------------------------------
>
>                 Key: FLUME-3352
>                 URL: https://issues.apache.org/jira/browse/FLUME-3352
>             Project: Flume
>          Issue Type: Bug
>          Components: Sinks+Sources
>    Affects Versions: 1.9.0
>            Reporter: taoyang
>            Priority: Blocker
>              Labels: patch, pull-request-available
>             Fix For: 1.10.0
>
>         Attachments: FLUME-3352-0.patch
>
>
> *Phenomenon*
> In many cases, we have just read permission on spoolDir and write permission on trackerDir.
> However whenever flume starts for spooldir source , it will always try to create a '.canary' file in the spooling directory.
> Then it leads to the failure of some processing unnecessarily.
> *Recur*
> (Usually spooldir is mounted readonly from a nas in production and this time we create a readonly directory instead.)
> First we create the spoolDir by root user and create a file in it and it is readonly for others by default.
> {code:java}
> su root
> mkdir /home/hadoop/testspooldir
> echo 'foo' > /home/hadoop/testspooldir/bar{code}
> Then switch to another user (hadoop) who runs flume and make sure it has read permission for the spooldir.
> {code:java}
> su hadoop
> mkdir /home/hadoop/testtrackerdir
> ll /home/hadoop/testspooldir
> >> total 4-rw-r--r-- 1 root root 4 Jan 16 19:15 bar{code}
> now create the example.conf:
> {code:java}
> a1.sources = r1
> a1.sinks = k1
> a1.channels = c1
> a1.sources.r1.type = spooldir
> a1.sources.r1.deletePolicy = never
> a1.sources.r1.spoolDir = /home/hadoop/testspooldir
> a1.sources.r1.trackerDir = /home/hadoop/testtrackerdir
> a1.sources.r1.trackingPolicy = tracker_dir
> a1.sinks.k1.type = logger
> a1.channels.c1.type = memory
> a1.channels.c1.capacity = 1000
> a1.channels.c1.transactionCapacity = 100
> a1.sources.r1.channels = c1
> a1.sinks.k1.channel = c1
> {code}
> and start flume with it
> {code:java}
> bin/flume-ng agent --conf conf --conf-file conf/example.conf --name a1 -Dflume.root.logger=INFO,console{code}
> then the IOException is thrown.
> {code:java}
> 2020-01-16 19:16:12,777 (lifecycleSupervisor-1-0) [ERROR - org.apache.flume.lifecycle.LifecycleSupervisor$MonitorRunnable.run(LifecycleSupervisor.java:251)] Unabl2020-01-16 19:16:12,777 (lifecycleSupervisor-1-0) [ERROR - org.apache.flume.lifecycle.LifecycleSupervisor$MonitorRunnable.run(LifecycleSupervisor.java:251)] Unable to start EventDrivenSourceRunner: { source:Spool Directory source r1: { spoolDir: /home/hadoop/testspooldir } } - Exception follows.org.apache.flume.FlumeException: Unable to read and modify files in the spooling directory: /home/hadoop/testspooldir at org.apache.flume.client.avro.ReliableSpoolingFileEventReader.<init>(ReliableSpoolingFileEventReader.java:195) at org.apache.flume.client.avro.ReliableSpoolingFileEventReader.<init>(ReliableSpoolingFileEventReader.java:89) at org.apache.flume.client.avro.ReliableSpoolingFileEventReader$Builder.build(ReliableSpoolingFileEventReader.java:882) at org.apache.flume.source.SpoolDirectorySource.start(SpoolDirectorySource.java:111) at org.apache.flume.source.EventDrivenSourceRunner.start(EventDrivenSourceRunner.java:44) at org.apache.flume.lifecycle.LifecycleSupervisor$MonitorRunnable.run(LifecycleSupervisor.java:249) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)Caused by: java.io.IOException: Permission denied at java.io.UnixFileSystem.createFileExclusively(Native Method) at java.io.File.createTempFile(File.java:2024) at org.apache.flume.client.avro.ReliableSpoolingFileEventReader.<init>(ReliableSpoolingFileEventReader.java:185) ... 12 more{code}
> *Fix*
> We just add the condition where this trick is necessary.
> The pr/patch will be submitted as as shown below.
> Or let it still exist and using warning log instead of exception thrown is better?



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