Hi Jose,
On Fri, Aug 07, 2015 at 01:28:13PM -0400, Jose Nunez wrote:
> Hi,
>
> I need to express something similar to this:
>
> http-request set-header X-REQUEST-START t=%[Ts]%[ms]000
>
> (to append three "0"s at the end of the timestamp with milliseconds).
>
> I have tried with other ways to append the three "0"s at the end:
>
> http-request set-header X-REQUEST-START t=%Ts%[ms]\x30\x30\x30
>
> and
>
> http-request set-header X-REQUEST-START t=%Ts%ms\x30\x30\x30
>
> and no avail either.
You've met the limits of the log format which is not a language and
which requires some delimiters to be detected. Unfortunately it doesn't
have any delimiter which doesn't appear in the output. I found a way to
abuse it using %[] to mark a new word (since %[] detects the end of the
current block using the closing bracket). Using just "%[]" emits a warning
and does exactly what you want. A cleaner method in 1.6 consists in emitting
an empty string as a delimitor : %[str()]. In 1.5, there is no str(), but
you can use %[env()] which will retrieve the contents of the environment
variable with no name, it doesn't exist so it returns an empty string. Yes
I know that's ugly, but the log format has gone far beyond its design goals
already!
Thus it will give you this in 1.5 :
http-request set-header X-REQUEST-START t=%Ts%ms%[env()]000
In 1.6 you can also do that :
http-request set-header X-REQUEST-START t=%Ts%ms%[str(000)]
Also, please note that what you're doing above only works because %ms is
left-padded with zeroes. I'm not seeing this documented anywhere though.
Willy
