I thought you didn’t want to write to a file? The Chronicle stuff Remko is linking to is also worth exploring.
Ralph > On Sep 26, 2016, at 5:04 PM, Gary Gregory <garydgreg...@gmail.com> wrote: > > oh... what about our own > http://logging.apache.org/log4j/2.x/manual/appenders.html#MemoryMappedFileAppender > > <http://logging.apache.org/log4j/2.x/manual/appenders.html#MemoryMappedFileAppender> > > ? > > Gary > > On Mon, Sep 26, 2016 at 4:59 PM, Remko Popma <remko.po...@gmail.com > <mailto:remko.po...@gmail.com>> wrote: > In addition to the Flume based solution, here is another alternative idea: > use Peter Lawrey's Chronicle[1] library to store log events in a memory > mapped file. > > The appender can just keep adding events without worrying about overflowing > the memory. > > The client that reads from this file can be in a separate thread (even a > separate process by the way) and can read as much as it wants, and send it to > the server. > > Serialization: You can either serialize log events to the target format > before storing them in Chronicle (so you have binary blobs in each Chronicle > excerpt), client reads these blobs and sends them to the server as is. Or you > can use the Chronicle Log4j2 appender[2] to store the events in Chronicle > format. The tests[3] show how to read LogEvent objects from the memory mapped > file, and the client would be responsible for serializing these log events to > the target format before sending data to the server. > > [1]: https://github.com/peter-lawrey/Java-Chronicle > <https://github.com/peter-lawrey/Java-Chronicle> > [2]: https://github.com/OpenHFT/Chronicle-Logger > <https://github.com/OpenHFT/Chronicle-Logger> > [3]: > https://github.com/OpenHFT/Chronicle-Logger/blob/master/logger-log4j-2/src/test/java/net/openhft/chronicle/logger/log4j2/Log4j2IndexedChronicleTest.java > > <https://github.com/OpenHFT/Chronicle-Logger/blob/master/logger-log4j-2/src/test/java/net/openhft/chronicle/logger/log4j2/Log4j2IndexedChronicleTest.java> > > Remko > > Sent from my iPhone > > On 2016/09/27, at 5:57, Gary Gregory <garydgreg...@gmail.com > <mailto:garydgreg...@gmail.com>> wrote: > >> Please allow me to restate the use case I have for the CollectionAppender, >> which is separate from any Flume-based or Syslog-based solution, use cases I >> also have. Well, I have a Syslog use case, and whether or not Flume is in >> the picture will really be a larger discussion in my organization due to the >> requirement to run a Flume Agent.) >> >> A program (like a JDBC driver already using Log4j) communicates with another >> (like a DBMS, not written in Java). The client and server communicate over a >> proprietary socket protocol. The client sends a list of buffers (in one go) >> to the server to perform one or more operations. One kind of buffer this >> protocol defines is a log buffer (where each log event is serialized in a >> non-Java format.) This allows each communication from the client to the >> server to say "This is what's happened up to now". What the server does with >> the log buffers is not important for this discussion. >> >> What is important to note is that the log buffer and other buffers go to the >> server in one BLOB; which is why I cannot (in this use case) send log events >> by themselves anywhere. >> >> I see that something (a CollectionAppender) must collect log events until >> the client is ready to serialize them and send them to the server. Once the >> events are drained out of the Appender (in one go by just getting the >> collection), events can collect in a new collection. A synchronous drain >> operation would create a new collection and return the old one. >> >> The question becomes: What kind of temporary location can the client use to >> buffer log event until drain time? A Log4j Appender is a natural place to >> collect log events since the driver uses Log4j. The driver will make its >> business to drain the appender and work with the events at the right time. I >> am thinking that the Log4j Appender part is generic enough for inclusion in >> Log4j. >> >> Further thoughts? >> >> Thank you all for reading this far! >> Gary >> >> On Sun, Sep 25, 2016 at 1:20 PM, Ralph Goers <ralph.go...@dslextreme.com >> <mailto:ralph.go...@dslextreme.com>> wrote: >> I guess I am not understanding your use case quite correctly. I am thinking >> you have a driver that is logging and you want those logs delivered to some >> other location to actually be written. If that is your use case then the >> driver needs a log4j2.xml that configures the FlumeAppender with either the >> memory or file channel (depending on your needs) and points to the server(s) >> that is/are to receive the events. The FlumeAppender handles sending them in >> batches with whatever size you want (but will send them in smaller amounts >> if they are in the channel too long). Of course you would need the >> log4j-flume and flume jars. So on the driver side you wouldn’t need to write >> anything, just configure the appender and make sure the jars are there. >> >> For the server that receives them you would also need Flume. Normally this >> would be a standalone component, but it really wouldn’t be hard to >> incorporate it into some other application. The only thing you would have to >> write would be the sink that writes the events to the database or whatever. >> To incorporate it into an application you would have to look at the main() >> method of flume and covert that to be a thread that you kick off. >> >> Ralph >> >> >> >>> On Sep 25, 2016, at 12:01 PM, Gary Gregory <garydgreg...@gmail.com >>> <mailto:garydgreg...@gmail.com>> wrote: >>> >>> Hi Ralph, >>> >>> Thanks for your feedback. Flume is great in the scenarios that do not >>> involve sending a log buffer from the driver itself. >>> >>> I can't require a Flume Agent to be running 'on the side' for the use case >>> where the driver chains a log buffer at the end of the train of database IO >>> buffer. For completeness talking about this Flume scenario, if I read you >>> right, I also would need to write a custom Flume sink, which would also be >>> in memory, until the driver is ready to drain it. Or, I could query some >>> other 'safe' and 'reliable' Flume sink that the driver could then drain of >>> events when it needs to. >>> >>> Narrowing down on the use case where the driver chains a log buffer at the >>> end of the train of database IO buffer, I'll think I have to see about >>> converting the Log4j ListAppender into a more robust and flexible version. >>> I think I'll call it a CollectionAppender and allow various Collection >>> implementations to be plugged in. >>> >>> Gary >>> >>> Gary >>> >>> On Sat, Sep 24, 2016 at 3:44 PM, Ralph Goers <ralph.go...@dslextreme.com >>> <mailto:ralph.go...@dslextreme.com>> wrote: >>> If you are buffering events in memory you run the risk of losing events if >>> something should fail. >>> >>> That said, if I had your requirements I would use the FlumeAppender. It has >>> either an in-memory option to buffer as you are suggesting or it can write >>> to a local file to prevent data loss if that is a requirement. It already >>> has the configuration options you are looking for and has been well tested. >>> The only downside is that you need to have either a Flume instance >>> receiving the messages are something that can receive Flume events over >>> Avro, but it is easier just to use Flume and write a custom sink to do what >>> you want with the data. >>> >>> Ralph >>> >>>> On Sep 24, 2016, at 3:13 PM, Gary Gregory <garydgreg...@gmail.com >>>> <mailto:garydgreg...@gmail.com>> wrote: >>>> >>>> Hi All, >>>> >>>> I can't believe it, but through a convoluted use-case, I actually need an >>>> in-memory list appender, very much like our test-only ListAppender. >>>> >>>> The requirement is as follows. >>>> >>>> We have a JDBC driver and matching proprietary database that specializes >>>> in data virtualization of mainframe resources like DB2, VSAM, IMS, and all >>>> sorts of non-SQL data sources >>>> (http://www.rocketsoftware.com/products/rocket-data/rocket-data-virtualization >>>> >>>> <http://www.rocketsoftware.com/products/rocket-data/rocket-data-virtualization>) >>>> >>>> >>>> The high level requirement is to merge the driver log into the server's >>>> log for full-end to end tractability and debugging. >>>> >>>> When the driver is running on the z/OS mainframe, it can be configured >>>> with a z/OS specific Appender that can talk to the server log module >>>> directly. >>>> >>>> When the driver is running elsewhere, it can talk to the database via a >>>> Syslog socket Appender. This requires more set up on the server side and >>>> for the server to do special magic to know how the incoming log events >>>> match up with server operations. Tricky. >>>> >>>> The customer should also be able to configure the driver such that anytime >>>> the driver communicates to the database, it sends along whatever log >>>> events have accumulated since the last client-server roundtrip. This >>>> allows the server to match exactly the connection and operations the >>>> client performed with the server's own logging. >>>> >>>> In order to do that I need to buffer all log events in an Appender and >>>> when it's time, I need to get the list of events and reset the appender to >>>> a new empty list so events can keep accumulating. >>>> >>>> My proposal is to either turn our ListAppender into such an appender. For >>>> sanity, the appender could be configured with various sizing policies: >>>> >>>> - open: the list grows unbounded >>>> - closed: the list grows to a given size and _new_ events are dropped on >>>> the floor beyond that >>>> - latest: the list grows to a given size and _old_ events are dropped on >>>> the floor beyond that >>>> >>>> Thoughts? >>>> >>>> Gary >>>> >>>> -- >>>> E-Mail: garydgreg...@gmail.com <mailto:garydgreg...@gmail.com> | >>>> ggreg...@apache.org <mailto:ggreg...@apache.org> >>>> Java Persistence with Hibernate, Second Edition >>>> <http://www.manning.com/bauer3/> >>>> JUnit in Action, Second Edition <http://www.manning.com/tahchiev/> >>>> Spring Batch in Action <http://www.manning.com/templier/> >>>> Blog: http://garygregory.wordpress.com <http://garygregory.wordpress.com/> >>>> Home: http://garygregory.com/ <http://garygregory.com/> >>>> Tweet! http://twitter.com/GaryGregory <http://twitter.com/GaryGregory> >>> >>> >>> >>> -- >>> E-Mail: garydgreg...@gmail.com <mailto:garydgreg...@gmail.com> | >>> ggreg...@apache.org <mailto:ggreg...@apache.org> >>> Java Persistence with Hibernate, Second Edition >>> <http://www.manning.com/bauer3/> >>> JUnit in Action, Second Edition <http://www.manning.com/tahchiev/> >>> Spring Batch in Action <http://www.manning.com/templier/> >>> Blog: http://garygregory.wordpress.com <http://garygregory.wordpress.com/> >>> Home: http://garygregory.com/ <http://garygregory.com/> >>> Tweet! http://twitter.com/GaryGregory <http://twitter.com/GaryGregory> >> >> >> >> -- >> E-Mail: garydgreg...@gmail.com <mailto:garydgreg...@gmail.com> | >> ggreg...@apache.org <mailto:ggreg...@apache.org> >> Java Persistence with Hibernate, Second Edition >> <http://www.manning.com/bauer3/> >> JUnit in Action, Second Edition <http://www.manning.com/tahchiev/> >> Spring Batch in Action <http://www.manning.com/templier/> >> Blog: http://garygregory.wordpress.com <http://garygregory.wordpress.com/> >> Home: http://garygregory.com/ <http://garygregory.com/> >> Tweet! http://twitter.com/GaryGregory <http://twitter.com/GaryGregory> > > > -- > E-Mail: garydgreg...@gmail.com <mailto:garydgreg...@gmail.com> | > ggreg...@apache.org <mailto:ggreg...@apache.org> > Java Persistence with Hibernate, Second Edition > <http://www.manning.com/bauer3/> > JUnit in Action, Second Edition <http://www.manning.com/tahchiev/> > Spring Batch in Action <http://www.manning.com/templier/> > Blog: http://garygregory.wordpress.com <http://garygregory.wordpress.com/> > Home: http://garygregory.com/ <http://garygregory.com/> > Tweet! http://twitter.com/GaryGregory <http://twitter.com/GaryGregory>
