[wildfly-dev] Design Proposal: Log Viewer

[Scott Marlow]

On 06/11/2014 11:01 AM, James R. Perkins wrote:
>
> On 06/10/2014 06:53 PM, Scott Marlow wrote:
>> Any concern about the number of users viewing the server logs at the
>> same time and the impact that could have on a system under load?  For
>> example, if a bunch of users arrive at work around the same time and
>> they are all curious about how things went last night.  They all could
>> make a request to show the last 1000 lines of the server.log file (which
>> could peg the CPU).  You might ask why a large number of users have
>> access to view the logs but the problem is still worth considering.
> Actually it's not something I've thought of. Though I suppose this could
> be an issue with any operation that returns large results.

Would be good to have feedback on how many users are likely to 
concurrently view logs.  I suspect the count will be higher than we 
might expect (depending on which users have access for a particular 
deployment).

One possible solution could be a 
http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/Semaphore.html 
that is configured for the maximum number of users allowed to view logs 
concurrently.  For example, if the number of Semaphore permits is 
configured for five and eighty users are trying to view logs at the same 
time, logs will be returned for five users at a time (until all users 
have received their logs or a timeout occurs).

There are probably other ways to deal with this as well.

>>
>>
>> On 06/10/2014 07:33 PM, James R. Perkins wrote:
>>> While there wasn't a huge talk about this at the Brno meeting I know
>>> Heiko brought it up as part of the extended metrics. It's on some future
>>> product road maps as well too. I figured I might as well bring it up
>>> here and get opinions on it.
>>>
>>> This design proposal covers how capturing log messages. The "viewer"
>>> will likely be an operation that returns an object list of log record
>>> details. The design of how a GUI view would look/work is beyond the
>>> scope of this proposal.
>>>
>>> There is currently an operation to view a log file. This has several
>>> limitations. The file must be defined as a known file handler. There is
>>> also no way to filter results, e.g. errors only. If per-deployment
>>> logging is used, those log messages are not viewable as the files are
>>> not accessible.
>>>
>>> For the list of requirements I'm going to be lazy and just give the link
>>> the wiki page https://community.jboss.org/wiki/LogViewerDesign.
>>>
>>> Implementation:
>>>
>>> 1) There will be a new resource on the logging subsystem resource that
>>> can be enabled or disabled, currently called log-collector. Probably
>>> some attributes, but I'm not sure what will need to be configurable at
>>> this point. This will likely act like a handler and be assignable only
>>> to loggers and not the async-handler.
>>>
>>> 2) If a deployment uses per-deployment logging then a separate
>>> log-collector will need to be added to the deployments log context
>>>
>>> 3) Logging profiles will also have their own log-collector.
>>>
>>> 4) The messages should be written asynchronously and to a file in some
>>> kind of formatted structure. The structure will likely be JSON.
>>>
>>> 5) An operation to query the messages will need to be create. This
>>> operation should allow the results to be filtered on various fields as
>>> well as limit the data set returned and allow for a starting position.
>>>
>>> 6) All operations associated with view the log should use RBAC to
>>> control the access.
>>>
>>> 7) Audit logs will eventually need to be viewable and queryable. This
>>> might be separate from the logging subsystem as it is now, but it will
>>> need to be done.
>>>
>>>
>>> There are things like how long or how many records should we keep that
>>> needs to be determined. This could possibly be configurable via
>>> attributes on the resource.
>>>
>>> This is about all I've got at this point. I'd appreciate any feedback.
>>>
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