9.1. Trace

filter trace [name ] [random-parsing] [random-forwarding] [hexdump]

Arguments:

<name>               is an arbitrary name that will be reported in
                     messages. If no name is provided, "TRACE" is used.
 
<random-parsing>     enables the random parsing of data exchanged between
                     the client and the server. By default, this filter
                     parses all available data. With this parameter, it
                     only parses a random amount of the available data.
 
<random-forwarding>  enables the random forwarding of parsed data. By
                     default, this filter forwards all previously parsed
                     data. With this parameter, it only forwards a random
                     amount of the parsed data.
 
<hexdump>             dumps all forwarded data to the server and the client.

This filter can be used as a base to develop new filters. It defines all
callbacks and print a message on the standard error stream (stderr) with useful
information for all of them. It may be useful to debug the activity of other
filters or, quite simply, HAProxy's activity.
 
Using <random-parsing> and/or <random-forwarding> parameters is a good way to
tests the behavior of a filter that parses data exchanged between a client and
a server by adding some latencies in the processing.