It does the opposite of 'set-var' action/converter. It is really useful for
per-process variables. But, it can be used for any scope.
The lua function 'unset_var' has also been added.
This function, unsurprisingly, sets a variable value only if it already
exists. In other words, this function will succeed only if the variable was
found somewhere in the configuration during HAProxy startup.
It will be used by SPOE filter. So an agent will be able to set a value only for
existing variables. This prevents an agent to create a very large number of
unused variables to flood HAProxy and exhaust the memory reserved to variables..
This is the continuation of previous patch called "BUG/MAJOR: samples:
check smp->strm before using it".
It happens that variables may have a session-wide scope, and that their
session is retrieved by dereferencing the stream. But nothing prevents them
from being used from a streamless context such as tcp-request connection,
thus crashing the process. Example :
tcp-request connection accept if { src,set-var(sess.foo) -m found }
In order to fix this, we have to always ensure that variable manipulation
only happens via the sample, which contains the correct owner and context,
and that we never use one from a different source. This results in quite a
large change since a lot of functions are inderctly involved in the call
chain, but the change is easy to follow.
This fix must be backported to 1.6, and requires the last two patches.
This patch adds two functions used for variable acces using the
variable full name. If the variable doesn't exists in the variable
pool name, it is created.
This patch adds support of variables during the processing of each stream. The
variables scope can be set as 'session', 'transaction', 'request' or 'response'.
The variable type is the type returned by the assignment expression. The type
can change while the processing.
The allocated memory can be controlled for each scope and each request, and for
the global process.
Christopher Faulet
Willy Tarreau
Thierry FOURNIER