[wildfly-dev] Reading Logs from Web Console

[Ondrej Zizka]

1) Could it have a "read-log-file()" without name= specified, which 
would read the "current" log file?
2) Regarding security - what, besides logs, do we expect to be in the 
log dir? Could the admin block it by setting write-only rights?

Ondra

On 25.9.2013 02:40, James R. Perkins wrote:
> I'm replying to this old thread to reopen this conversation about 
> reading log files. I've complete some work [1] on reading log files 
> via an operation. This is not exactly like the JIRA suggests where it 
> would only read the last 10 error messages. All this change allows is 
> the raw contents of the file to be read. The idea is this could be 
> used to read the entire contents of the log file as a whole, or in chunks.
>
> What I've done is added two new operations list-log-files and 
> read-log-file.
>
> The list-log-files simply lists all files in the jboss.server.log.dir. 
> This may or may not be a good idea really. I can see some potential 
> security risks here mainly just seeing files that may contain 
> sensitive data. One way I've thought of to get around that is read the 
> logging subsystem model and only show files from known types like the 
> file-handlers. The main issue with that is there is no good way to get 
> this to work for custom-handlers.
>
> The read-log-file simple does what it says and reads the contents of a 
> log file line by line. Reading line by line should work for the most 
> part unless the an non-standard line delimiter is used. There are 5 
> options for this option;
>
>   * name (required): the name of the log file to read
>   * encoding: the encoding for the log file
>   * lines: the number of lines to read, defaults to 10
>   * skip: the number of lines to skip before adding the results
>   * tail: true to read from the bottom up, default is true
>
> The result of this is just a list of lines with the \n or \r\n 
> stripped. Just to clarify too a line means a line in the file, not a 
> log record e.g. stack traces are generally composed of multiple lines.
>
> So this begs the question, will this work for what we want? What 
> concerns does anyone else have?
>
> I have not yet submitted a PR yet as I wanted to get some feedback 
> before we bake it in.
>
>
> [1]: https://github.com/jamezp/wildfly/compare/WFLY-280-read
>
>
> On 08/14/2013 10:03 AM, James R. Perkins wrote:
>> I had posted this to another list, but this is a more appropriate 
>> place for it. I think there needs to be a general discussion around 
>> this as it's been mentioned, at least to me, a few times here and 
>> there and I know Heiko raised the issue some time a go now.
>>
>> The original JIRA, WFLY-280[1], is to display the last 10 error 
>> messages only. To be honest I wouldn't find that very useful. To me 
>> if I'm looking for logs I want to see all logs, but that's not always 
>> so easy. Like the syslog-handler which doesn't log to a file so there 
>> is no way to read those messages back.
>>
>> The current plan for the last 10 error messages is we store messages 
>> in a queue that can be accessed via an operation. This works fine 
>> until the error message you're interested in is 11 or you want to see 
>> warning messages.
>>
>> Another option I had come up with is reading back the contents of the 
>> file, for example the server.log. This could be problematic too in 
>> that there is no way to filter information like only see error 
>> messages or only see warning messages. To solve this I have 
>> considered creating a JSON formatter so the results could be queried, 
>> but I don't think it should be a default which would mean it's not 
>> reliable for the console to assume it's getting back JSON.
>>
>> I've also thought about, haven't tested this and it may not work at 
>> all, creating a handler that uses websockets to send messages. I'm 
>> not sure how well this would work and it's possible it may not even 
>> work for bootstrap logging.
>>
>> With regards to audit logging, we're probably going to have to do 
>> something totally different from what we'll do in the logging 
>> subsystem since it doesn't use standard logging.
>>
>> I guess the bottom line is what does the console want to see? Do you 
>> want to see all raw text log messages? Do you want all messages but 
>> in a format like JSON that you can query/filter? Do you really want 
>> only the last 10 error messages only? All or none of these might be 
>> possible, but I really need to understand the needs before I can 
>> explore more in depth what the best option would be.
>>
>> [1]: https://issues.jboss.org/browse/WFLY-280
>> -- 
>> James R. Perkins
>> Red Hat JBoss Middleware
>
> -- 
> James R. Perkins
> Red Hat JBoss Middleware
>
>
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