+1, awesome summary Connor! In the future, maybe someone wants to take a look at doing something with inotify, i.e. https://github.com/manos/python-inotify-tail_example/blob/master/tail-F_inotify.py and inode information to create a reliable "tail" implementation that is aware of file rolling and keeps track of which files have been processed (and how much) based on their inodes. It could post to the HTTP source as an integration point. Or it could be written in C/C++, or using JNI in Java. Sadly it would likely not be portable between most OSes.
Such a thing cannot be written reliably in pure Java, because at least JDK6 does not have access to inode information, so you end up with really nasty race conditions. Without reliability guarantees, you may as well use tail -F. Regards, Mike On Fri, Jan 18, 2013 at 1:13 AM, Connor Woodson <[email protected]>wrote: > The Spooling Directory Source is best used for sending old data / backups > through Flume, as opposed to trying to use it for realtime data (due to, as > you discovered, you aren't supposed to write directly to a file in that > directory but rather place closed files in there). You could implement > what Mike mentioned above about rolling the logs into the spooling > directory, but there are other options. > > If you are looking to pull data in real time, the Exec > Source<http://flume.apache.org/FlumeUserGuide.html#exec-source>mentioned > above does work. The one downside with this is that this source > is not the most reliable, as is mentioned in the red box in that link, and > you will have to monitor it to make sure it hasn't crashed. However, other > than the Spooling Directory source and any custom source you write, this is > the only other pulling source. > > But depending on how your system is set up, you could set up a system for > pushing your logs into Flume. Here are some options: > > If the log files you want to capture use Log4J, then there is a Log4JAppender > <http://flume.apache.org/FlumeUserGuide.html#log4j-appender>which will > send events directly to Flume. The benefit to this is that you let Flume > take control of the events right as they are generated; they are sent > through Avro to your specified host/ip where you will have a Flume agent > with an Avro > Source<http://flume.apache.org/FlumeUserGuide.html#flume-sources>running. > > Another alternative to the above if you don't use Log4J but you do have > direct control over the application is to use the Embedded Flume > Agent<https://github.com/apache/flume/blob/trunk/flume-ng-doc/sphinx/FlumeDeveloperGuide.rst#embedded-agent>. > This is even more powerful than the log4j appender as you have more control > over how it works and you are able to use the Flume channels with it. This > would end up pushing events via Avro to your Flume agent to then > collect/process/store. > > There are a variety of network methods that can communicate with Flume. > Flume has support for listening on a specified port with the Netcat > Source<http://flume.apache.org/FlumeUserGuide.html#netcat-source>, > getting events via HTTP > Post<http://flume.apache.org/FlumeUserGuide.html#http-source>messages, and if > your application uses Syslog that's > supported <http://flume.apache.org/FlumeUserGuide.html#syslog-sources> as > well. > > In summation, if you need to set up a pulling system you will need to > place a Flume agent on each of your servers and have it use a Spooling > Directory or Exec source; or if your system is configurable enough you will > be able to modify it in various possible ways to push the logs to Flume. > > I hope some of that was helpful, > > - Connor > > > On Fri, Jan 18, 2013 at 12:18 AM, Henry Ma <[email protected]>wrote: > >> We have an advertisement system, which owns hundreds of servers running >> service such as resin/nginx, and each of them generates log files to a >> local location every seconds. What we need is to collect all the log files >> in time to a central storage such as MooseFS for real-time analysis, and >> then archive them to HDFS by hour. >> >> We want to deploy Flume to collect log files as soon as they are >> generated from nearly one hundred servers (the server list may be added or >> removed at any time) to a central location, and then archive to HDFS each >> hour. >> >> By now the log files cannot be pushed to any collecting system. We want >> to the collecting system can PULL all of them remotely. >> >> Can you give me some guide? Thanks! >> >> >> On Fri, Jan 18, 2013 at 3:45 PM, Mike Percy <[email protected]> wrote: >> >>> Can you provide more detail about what kinds of services? >>> >>> If you roll the logs every 5 minutes or so then you can configure the >>> spooling source to pick them up once they are rolled by either rolling them >>> into a directory for immutable files or using the trunk version of the >>> spooling file source to specify a filter to ignore files that don't match a >>> "rolled" pattern. >>> >>> You could also use exec source with "tail -F" but that is much more >>> unreliable than the spooling file source. >>> >>> Regards, >>> Mike >>> >>> >>> On Thu, Jan 17, 2013 at 10:23 PM, Henry Ma <[email protected]>wrote: >>> >>>> OK, thank you very much, now I know why the problem occurs. >>>> >>>> I am a new comer of Flume. Here is my scenario: using Flume to >>>> collecting from hundreds of directories from dozens of servers to a central >>>> storage. It seems that spooling directory source may not be the best >>>> choice. Can someone give me some advice about how to design the >>>> architecture? Which type of source and sink can fit? >>>> >>>> Thanks! >>>> >>>> >>>> On Fri, Jan 18, 2013 at 2:05 PM, Mike Percy <[email protected]> wrote: >>>> >>>>> Hi Henry, >>>>> The files must be immutable before putting them into the spooling >>>>> directory. So if you copy them from a different file system then you can >>>>> run into this issue. The right way to do it is to copy them to the same >>>>> file system and then atomically move them into the spooling directory. >>>>> >>>>> Regards, >>>>> Mike >>>>> >>>>> >>>>> On Thu, Jan 17, 2013 at 9:59 PM, Henry Ma <[email protected]>wrote: >>>>> >>>>>> Thank you very much! I clean all the related dir and restart again. I >>>>>> keep the source spooling dir empty, then start Flume, and then put some >>>>>> file into the spooling dir. But this time a new error occured: >>>>>> >>>>>> 13/01/18 13:44:24 INFO avro.SpoolingFileLineReader: Preparing to move >>>>>> file >>>>>> /disk2/mahy/FLUME_TEST/source/sspstat.log.20130118112700-20130118112800.hs016.ssp >>>>>> to /disk2/mahy/FLUME_TEST/ >>>>>> source/sspstat.log.20130118112700-20130118112800.hs016.ssp.COMPLETED >>>>>> 13/01/18 13:44:24 ERROR source.SpoolDirectorySource: Uncaught >>>>>> exception in Runnable >>>>>> java.lang.IllegalStateException: File has changed size since being >>>>>> read: >>>>>> /disk2/mahy/FLUME_TEST/source/sspstat.log.20130118112700-20130118112800.hs016.ssp >>>>>> at >>>>>> org.apache.flume.client.avro.SpoolingFileLineReader.retireCurrentFile(SpoolingFileLineReader.java:241) >>>>>> at >>>>>> org.apache.flume.client.avro.SpoolingFileLineReader.readLines(SpoolingFileLineReader.java:185) >>>>>> at >>>>>> org.apache.flume.source.SpoolDirectorySource$SpoolDirectoryRunnable.run(SpoolDirectorySource.java:135) >>>>>> at >>>>>> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441) >>>>>> at >>>>>> java.util.concurrent.FutureTask$Sync.innerRunAndReset(FutureTask.java:317) >>>>>> at >>>>>> java.util.concurrent.FutureTask.runAndReset(FutureTask.java:150) >>>>>> at >>>>>> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$101(ScheduledThreadPoolExecutor.java:98) >>>>>> at >>>>>> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.runPeriodic(ScheduledThreadPoolExecutor.java:180) >>>>>> at >>>>>> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:204) >>>>>> at >>>>>> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) >>>>>> at >>>>>> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) >>>>>> at java.lang.Thread.run(Thread.java:662) >>>>>> 13/01/18 13:44:24 ERROR source.SpoolDirectorySource: Uncaught >>>>>> exception in Runnable >>>>>> java.io.IOException: Stream closed >>>>>> at java.io.BufferedReader.ensureOpen(BufferedReader.java:97) >>>>>> at java.io.BufferedReader.readLine(BufferedReader.java:292) >>>>>> at java.io.BufferedReader.readLine(BufferedReader.java:362) >>>>>> at >>>>>> org.apache.flume.client.avro.SpoolingFileLineReader.readLines(SpoolingFileLineReader.java:180) >>>>>> at >>>>>> org.apache.flume.source.SpoolDirectorySource$SpoolDirectoryRunnable.run(SpoolDirectorySource.java:135) >>>>>> at >>>>>> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441) >>>>>> at >>>>>> java.util.concurrent.FutureTask$Sync.innerRunAndReset(FutureTask.java:317) >>>>>> at >>>>>> java.util.concurrent.FutureTask.runAndReset(FutureTask.java:150) >>>>>> at >>>>>> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$101(ScheduledThreadPoolExecutor.java:98) >>>>>> at >>>>>> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.runPeriodic(ScheduledThreadPoolExecutor.java:180) >>>>>> at >>>>>> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:204) >>>>>> at >>>>>> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) >>>>>> at >>>>>> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) >>>>>> at java.lang.Thread.run(Thread.java:662) >>>>>> 13/01/18 13:44:25 ERROR source.SpoolDirectorySource: Uncaught >>>>>> exception in Runnable >>>>>> java.io.IOException: Stream closed >>>>>> at java.io.BufferedReader.ensureOpen(BufferedReader.java:97) >>>>>> >>>>>> >>>>>> I think it is a typical scenario: Flume is watching some dirs and >>>>>> collecting new arriving files. I don't know why the exception " File has >>>>>> changed size since being read" was throwed and how to avoid it. Can you >>>>>> give some advice and guide? Thanks! >>>>>> >>>>>> >>>>>> On Fri, Jan 18, 2013 at 1:48 PM, Patrick Wendell >>>>>> <[email protected]>wrote: >>>>>> >>>>>>> Hey Henry, >>>>>>> >>>>>>> The Spooling source assumes that each file is uniquely named. If it >>>>>>> sees that new file name has arrived that it already processed (and >>>>>>> has >>>>>>> rolled over to a COMPLETED file), it throws an error and shuts down. >>>>>>> This is to try and prevent sending duplicate data downstream. >>>>>>> >>>>>>> Probably the best idea is to clear out the COMPLETED file (and the >>>>>>> original file, if they are indeed the same one) and restart. >>>>>>> >>>>>>> - Patrick >>>>>>> >>>>>>> On Thu, Jan 17, 2013 at 9:31 PM, Brock Noland <[email protected]> >>>>>>> wrote: >>>>>>> > Hmm, I think this is probaly the root cause. Looks like their was a >>>>>>> > file with that name already used. >>>>>>> > >>>>>>> > 13/01/18 13:16:59 ERROR source.SpoolDirectorySource: Uncaught >>>>>>> > exception in Runnable >>>>>>> > java.lang.IllegalStateException: File name has been re-used with >>>>>>> > different files. Spooling assumption violated for >>>>>>> > >>>>>>> /disk2/mahy/FLUME_TEST/source/sspstat.log.20130118100000-20130118100100.hs009.ssp.COMPLETED >>>>>>> > at >>>>>>> org.apache.flume.client.avro.SpoolingFileLineReader.retireCurrentFile(SpoolingFileLineReader.java:272) >>>>>>> > at >>>>>>> org.apache.flume.client.avro.SpoolingFileLineReader.readLines(SpoolingFileLineReader.java:185) >>>>>>> > at >>>>>>> org.apache.flume.source.SpoolDirectorySource$SpoolDirectoryRunnable.run(SpoolDirectorySource.java:135) >>>>>>> > at >>>>>>> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441) >>>>>>> > at >>>>>>> java.util.concurrent.FutureTask$Sync.innerRunAndReset(FutureTask.java:317) >>>>>>> > at >>>>>>> java.util.concurrent.FutureTask.runAndReset(FutureTask.java:150) >>>>>>> > at >>>>>>> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$101(ScheduledThreadPoolExecutor.java:98) >>>>>>> > at >>>>>>> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.runPeriodic(ScheduledThreadPoolExecutor.java:180) >>>>>>> > at >>>>>>> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:204) >>>>>>> > at >>>>>>> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) >>>>>>> > at >>>>>>> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) >>>>>>> > at java.lang.Thread.run(Thread.java:662) >>>>>>> > >>>>>>> > On Thu, Jan 17, 2013 at 9:22 PM, Henry Ma <[email protected]> >>>>>>> wrote: >>>>>>> >> attached is the log file. >>>>>>> >> >>>>>>> >> the content of conf file: >>>>>>> >> # Name the components on this agent >>>>>>> >> a1.sources = r1 >>>>>>> >> a1.sinks = k1 >>>>>>> >> a1.channels = c1 >>>>>>> >> >>>>>>> >> # Describe/configure the source >>>>>>> >> a1.sources.r1.type = spooldir >>>>>>> >> a1.sources.r1.spoolDir = /disk2/mahy/FLUME_TEST/source >>>>>>> >> a1.sources.r1.channels = c1 >>>>>>> >> >>>>>>> >> # Describe the sink >>>>>>> >> a1.sinks.k1.type = file_roll >>>>>>> >> a1.sinks.k1.sink.directory = /disk2/mahy/FLUME_TEST/sink >>>>>>> >> a1.sinks.k1.sink.rollInterval = 0 >>>>>>> >> >>>>>>> >> # Use a channel which buffers events in memory >>>>>>> >> a1.channels.c1.type = memory >>>>>>> >> a1.channels.c1.capacity = 99999 >>>>>>> >> #a1.channels.c1. = /disk2/mahy/FLUME_TEST/check >>>>>>> >> #a1.channels.c1.dataDirs = /disk2/mahy/FLUME_TEST/channel-data >>>>>>> >> >>>>>>> >> # Bind the source and sink to the channel >>>>>>> >> a1.sources.r1.channels = c1 >>>>>>> >> a1.sinks.k1.channel = c1 >>>>>>> >> >>>>>>> >> >>>>>>> >> On Fri, Jan 18, 2013 at 12:39 PM, Brock Noland < >>>>>>> [email protected]> wrote: >>>>>>> >>> >>>>>>> >>> Hi, >>>>>>> >>> >>>>>>> >>> Would you mind turning logging to debug and then posting your >>>>>>> full >>>>>>> >>> log/config? >>>>>>> >>> >>>>>>> >>> Brock >>>>>>> >>> >>>>>>> >>> On Thu, Jan 17, 2013 at 8:24 PM, Henry Ma < >>>>>>> [email protected]> wrote: >>>>>>> >>> > Hi, >>>>>>> >>> > >>>>>>> >>> > When using Spooling Directory Source in Flume NG 1.3.1, this >>>>>>> exception >>>>>>> >>> > happens: >>>>>>> >>> > >>>>>>> >>> > 13/01/18 11:37:09 ERROR source.SpoolDirectorySource: Uncaught >>>>>>> exception >>>>>>> >>> > in >>>>>>> >>> > Runnable >>>>>>> >>> > java.io.IOException: Stream closed >>>>>>> >>> > at java.io.BufferedReader.ensureOpen(BufferedReader.java:97) >>>>>>> >>> > at java.io.BufferedReader.readLine(BufferedReader.java:292) >>>>>>> >>> > at java.io.BufferedReader.readLine(BufferedReader.java:362) >>>>>>> >>> > at >>>>>>> >>> > >>>>>>> >>> > >>>>>>> org.apache.flume.client.avro.SpoolingFileLineReader.readLines(SpoolingFileLineReader.java:180) >>>>>>> >>> > at >>>>>>> >>> > >>>>>>> >>> > >>>>>>> org.apache.flume.source.SpoolDirectorySource$SpoolDirectoryRunnable.run(SpoolDirectorySource.java:135) >>>>>>> >>> > at >>>>>>> >>> > >>>>>>> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441) >>>>>>> >>> > at >>>>>>> >>> > >>>>>>> >>> > >>>>>>> java.util.concurrent.FutureTask$Sync.innerRunAndReset(FutureTask.java:317) >>>>>>> >>> > at >>>>>>> java.util.concurrent.FutureTask.runAndReset(FutureTask.java:150) >>>>>>> >>> > at >>>>>>> >>> > >>>>>>> >>> > >>>>>>> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$101(ScheduledThreadPoolExecutor.java:98) >>>>>>> >>> > at >>>>>>> >>> > >>>>>>> >>> > >>>>>>> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.runPeriodic(ScheduledThreadPoolExecutor.java:180) >>>>>>> >>> > at >>>>>>> >>> > >>>>>>> >>> > >>>>>>> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:204) >>>>>>> >>> > at >>>>>>> >>> > >>>>>>> >>> > >>>>>>> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) >>>>>>> >>> > at >>>>>>> >>> > >>>>>>> >>> > >>>>>>> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) >>>>>>> >>> > at java.lang.Thread.run(Thread.java:662) >>>>>>> >>> > >>>>>>> >>> > It usually happened when dropping some new files into the >>>>>>> spooling dir, >>>>>>> >>> > and >>>>>>> >>> > stop collecting file. Does someone know the reason and how to >>>>>>> avoid it? >>>>>>> >>> > >>>>>>> >>> > Thanks very much! >>>>>>> >>> > -- >>>>>>> >>> > Best Regards, >>>>>>> >>> > Henry Ma >>>>>>> >>> >>>>>>> >>> >>>>>>> >>> >>>>>>> >>> -- >>>>>>> >>> Apache MRUnit - Unit testing MapReduce - >>>>>>> >>> http://incubator.apache.org/mrunit/ >>>>>>> >> >>>>>>> >> >>>>>>> >> >>>>>>> >> >>>>>>> >> -- >>>>>>> >> Best Regards, >>>>>>> >> Henry Ma >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> > -- >>>>>>> > Apache MRUnit - Unit testing MapReduce - >>>>>>> http://incubator.apache.org/mrunit/ >>>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> Henry Ma >>>>>> >>>>> >>>>> >>>> >>>> >>>> -- >>>> Henry Ma >>>> >>> >>> >> >> >> -- >> Best Regards, >> 马环宇 >> 网易有道 EAD-Platform >> POPO: [email protected] >> MSN: [email protected] >> MOBILE: 18600601996 >> > >
