[syslog-ng] extracting jSON from $MESSAGE

Jorge Pereira jpereiran at gmail.com
Mon Jul 4 15:02:53 CEST 2016 

Hi Robert,

On Sun, Jul 3, 2016 at 2:26 PM, Fekete, Róbert <robert.fekete at balabit.com>
wrote:

> Hi Jorge,
>
> This seems to be a bit tricky message. If I see it correctly, after the
> syslog header, you have:
>
>  * some additional info that ends with [captcha] (is that literally
> [captcha], or it changes with every message?)
>

this value is dinamic.


>  * then you have some JSON
>  * "while logging request," string
>  * and finally some key:value pairs.
>
>
exactly!


> As a first try, I would use the csv-parser() to separate the message to
> the four blocks I listed above. Use syslog-ng OSE 3.7, because then you can
> use strings as delimiters (see
> https://www.balabit.com/sites/default/files/documents/syslog-ng-ose-latest-guides/en/syslog-ng-ose-guide-admin/html/reference-parsers-csv.html#csv-parser-delimiter).
> For example, you can use the ] character and the "while logging request,"
> string as delimiters.
> Then you can run the json-parser on the macro containing the JSON-part of
> the message, and a kv-parser with the : delimiter to parse the last block
> if needed. (Note that for kv-parser part you need a recent development
> version of syslog-ng).
>
>
Currently, I'm using the version 3.5.6. I will update.


> Make sure to use the prefix() option in the json-parser, because as I see
> the key:value block seems to have some of the same keys that the json block.
>
> BTW, is this a publicly available application that emits such a log
> message? It seems ideal to showcase the wide range of available syslog-ng
> parsers :)
>
>
yep! these are errors generated by OpenResty/Nginx. today I noticed that we
have another kind of error like the below sample.

2016/07/04 08:40:56 [error] 14011#0: *410 lua entry thread aborted:
runtime error: /usr/local/openresty/lua-my
<http://www.kipras.com/>/share/src/my
<http://www.kipras.com/>/util.lua:42: attempt to get length of local
'str' (a nil value)
stack traceback:
coroutine 0:
    /usr/local/openresty/lua-my <http://www.kipras.com/>/share/src/my
<http://www.kipras.com/>/util.lua: in function 'string_split'
    /usr/local/openresty/lua-my <http://www.kipras.com/>/my
<http://www.kipras.com/>/edge/upstream.lua:235: in function
'extract_peer'
    /usr/local/openresty/lua-my <http://www.kipras.com/>/my
<http://www.kipras.com/>/edge/upstream.lua:264: in function 'connect'
    /usr/local/openresty/lua-my <http://www.kipras.com/>/my
<http://www.kipras.com/>/edge/upstream.lua:147: in function 'request'
    /usr/local/openresty/lua-my <http://www.kipras.com/>/my
<http://www.kipras.com/>/edge/init.lua:85: in function
</usr/local/openresty/lua-my <http://www.kipras.com/>/my
<http://www.kipras.com/>/edge/init.lua:75>
    /usr/local/openresty/lua-my <http://www.kipras.com/>/my
<http://www.kipras.com/>/edge/init.lua:153: in function 'handler'
    /usr/local/openresty/lua-my <http://www.kipras.com/>/my
<http://www.kipras.com/>/edge/init.lua:166: in function 'content'
    .../openresty/nginx/../lua-my
<http://www.kipras.com/>/handlers/src/content.lua:1: in function
<.../openresty/nginx/../lua-my
<http://www.kipras.com/>/handlers/src/content.lua:1>, client:
192.168.33.1, server: www. <http://www.kipras.com/>my
<http://www.kipras.com/>.com <http://www.kipras.com/>, request: "GET
/favicon.ico HTTP/1.1", host: "www.my.com <http://www.kipras.com/>"


Now for me looks to be impossible to handler this... do you have some idea?
because, I receive this from nginx it over unix-stream and need to send to
a remote syslog-ng (collector) saving like:

/var/log/syslog-ng/www.my.com_error.log


> Regards,
> Robert
>
> On Sun, Jul 3, 2016 at 3:32 PM, Jorge Pereira <jpereiran at gmail.com> wrote:
>
>> Hi,
>>
>>     I am not sure about the best approach and way to fix my problem,
>> below more information.
>>
>> 1) I receive the below packet sent from a nginx/openresty instance.
>>
>> 2016/07/02 01:17:04 [emerg] 19081#0: *13163 [lua] init.lua:115: [captcha]
>> {"fail_count":"","response_code":200,"client_ip":"192.168.1.22","hostname":"server-lab01","request_id":"2016-07-02T01:17:03Z|9175f93c0c||i0Xb3BuBWV","host":"
>> www.mytest.com","http_request":{"verb":"GET","url":"\/","user-agent":"Mozilla\/5.0
>> (pc-x86_64-linux-gnu) Siege\/3.0.8","http_version":"1.1","all":"{\"host\":\"
>> www.mytest.com\",\"x-country-code\":\"US\",\"connection\":\"close\",\"accept\":\"*\\\/*\",\"x-client-ip\":\"192.168.1.22\",\"user-agent\":\"Mozilla\\\/5.0
>> (pc-x86_64-linux-gnu)
>> Siege\\\/3.0.8\",\"accept-encoding\":\"gzip\"}"},"geoip":{"location":"-90.5334,38.6500","city_name":"Chesterfield","country_name":"United
>> States","longitude":-90.5334,"area_code":314,"latitude":38.65,"country_code2":"US","country_code3":"USA"},"got":"","action":"show","expected":"h1szmM","webapp_domain":"
>> www.mytest.com"} while logging request, client: 192.168.1.22, server:
>> www.mytest.com, request: "GET / HTTP/1.1", host: "www.mytest.com"
>>
>> 2) In my server side, I need to save the logs following a value of *host:
>> "www.mytest.com <http://www.mytest.com>"* like:
>>
>> /var/log/syslog-ng/www.mytest.com.log
>>
>> 3) The problem is because the packet received has a part being a jSON,
>> but I can't use the *json-parser().*
>>
>> 4) What is the best approach? I have used:
>>
>> # Extracting only the jSON payload
>> rewrite p_nginx_wb_error_log_clean {
>>     subst(".*captcha] ", "", value("MESSAGE"), flags("global"));
>>     subst(" while logging request.*$", "", value("MESSAGE"),
>> flags("global"));
>> };
>>
>> parser p_nginx_wb_error_log_json {
>>     json-parser(
>>         marker("")
>>         prefix("j.")
>>     );
>> };
>>
>> destination d_nginx_wb_error_log {
>>
>> file("/var/log/syslog-ng/nginx/${j.webapp_domain:-unknow-payload}_error.log"
>>
>>
>>
>>          create_dirs(yes)
>>          owner("root")
>>          group("root")
>>          perm(0644)
>>          dir_perm(0755)
>>          template("${MSG}\n")
>>     );
>> };
>>
>> --
>> Jorge Pereira
>>
>>
>> ______________________________________________________________________________
>> Member info: https://lists.balabit.hu/mailman/listinfo/syslog-ng
>> Documentation:
>> http://www.balabit.com/support/documentation/?product=syslog-ng
>> FAQ: http://www.balabit.com/wiki/syslog-ng-faq
>>
>>
>>
>
>
> ______________________________________________________________________________
> Member info: https://lists.balabit.hu/mailman/listinfo/syslog-ng
> Documentation:
> http://www.balabit.com/support/documentation/?product=syslog-ng
> FAQ: http://www.balabit.com/wiki/syslog-ng-faq
>
>
>
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