This new target can be called from the frontend or the backend. It
is evaluated just before the backend choice and just before the server
choice. So, the input stream or HTTP request can be forwarded to a
server or to an internal service.
This patch only declares the execution timeout variable. The applet
must be respect or ignore it. For example an applet who doing some
network accesses and doesn't control its execution yime should use
this timeout.
this patch adds init function for the applet. the HAProxy standard
applet (peers, stats, lua) have no standard way for the applet
initialisation. This new function pointer have for goal to try to
standardize the applet initialization.
This flag is used by custom actions to know that they're called for the
first time. The only case where it's not set is when they're resuming
from a yield. It will be needed to let them know when they have to
allocate some resources.
The garbage collector is a little bit heavy to run, and it was added
only for cosockets. This patch prevent useless executions when no
cosockets are used.
When the channel is down, the applet is waked up. Before this patch,
the applet closes the stream and the unread data are discarded.
After this patch, the stream is not closed except if the buffers are
empty.
It will be closed later by the close function, or by the garbage collector.
The HAProxy Lua socket respects the Lua Socket tcp specs. these specs
are a little bit limited, it not permits to connect to unix socket.
this patch extends a little it the specs. It permit to accept a
syntax that begin with "unix@", "ipv4@", "ipv6@", "fd@" or "abns@".
Actions may yield but must not do it during the final call from a ruleset
because it indicates there will be no more opportunity to complete or
clean up. This is indicated by ACT_FLAG_FINAL in the action's flags,
which must be passed to hlua_resume().
Thanks to this, an action called from a TCP ruleset is properly woken
up and possibly finished when the client disconnects.
In HTTP it's more difficult to know when to pass the flag or not
because all actions are supposed to be final and there's no inspection
delay. Also, the input channel may very well be closed without this
being an error. So we only set the flag when option abortonclose is
set and the input channel is closed, which is the only case where the
user explicitly wants to forward a close down the chain.
This new flag indicates to a custom action that it must not yield because
it will not be called anymore. This addresses an issue introduced by commit
bc4c1ac ("MEDIUM: http/tcp: permit to resume http and tcp custom actions"),
which made it possible to yield even after the last call and causes Lua
actions not to be stopped when the session closes. Note that the Lua issue
is not fixed yet at this point. Also only TCP rules were handled, for now
HTTP rules continue to let the action yield since we don't know whether or
not it is a final call.
Since commit bc4c1ac ("MEDIUM: http/tcp: permit to resume http and tcp
custom actions"), some actions may yield and be called back when new
information are available. Unfortunately some of them may continue to
yield because they simply don't know that it's the last call from the
rule set. For this reason we'll need to pass a flag to the custom
action to pass such information and possibly other at the same time.
When a thread stops this patch forces a garbage collection which
cleanup and free the memory.
The HAProxy Lua Socket class contains an HAProxy session, so it
uses a big amount of memory, in other this Socket class uses a
filedescriptor and maintain a connection open.
If the class Socket is stored in a global variable, the Socket stay
alive along of the life of the process (except if it is closed by the
other size, or if a timeout is reached). If the class Socket is stored
in a local variable, it must die with this variable.
The socket is closed by a call from the garbage collector. And the
portability and use of a variable is known by the same garbage collector.
so, running the GC just after the end of all Lua code ensure that the
heavy resources like the socket class are freed quickly.
Not having the target set on the connection causes it to be released
at the last moment, and the destination address to randomly be valid
depending on the data found in the memory at this moment. In practice
it works as long as memory poisonning is disabled. The deep reason is
that connect_server() doesn't expect to be called with SF_ADDR_SET and
an existing connection with !reuse. This causes the release of the
connection, its reallocation (!reuse), and taking the address from the
newly allocated connection. This should certainly be improved.
Commit d75cb0f ("BUG/MAJOR: lua: segfault after the channel data is
modified by some Lua action.") introduced a regression causing an
action run from a TCP rule in an HTTP proxy to end in HTTP error
if it terminated cleanly, because it didn't parse the HTTP request!
Relax the test so that it takes into account the opportunity for the
analysers to parse the message.
The lua code must the the appropriate wakeup mechanism for cosockets.
It wakes them up from outside the stream and outside the applet, so it
shouldn't use the applet's wakeup callback which is designed only for
use from within the applet itself. For now it didn't cause any trouble
(yet).
When an action or a fetch modify the channel data, the http request parser
pointer become inconsistent. This patch detects the modification and call
again the parser.
The function lua_settable uses the metatable for acessing data,
so in the C part, we want to index value in the real table and
not throught the meta-methods. It's much faster this way.
When we call the function smp_prefetch_http(), if the txn is not initialized,
it doesn't work. This patch fix this. Now, smp_prefecth_http() permits to use
http with any proxy mode.
While the SI_ST_DIS state is set *after* doing the close on a connection,
it was set *before* calling release on an applet. Applets have no internal
flags contrary to connections, so they have no way to detect they were
already released. Because of this it happened that applets were closed
twice, once via si_applet_release() and once via si_release_endpoint() at
the end of a transaction. The CLI applet could perform a double free in
this case, though the situation to cause it is quite hard because it
requires that the applet is stuck on output in states that produce very
few data.
In order to solve this, we now assign the SI_ST_DIS state *after* calling
->release, and we refrain from doing so if the state is already assigned.
This makes applets work much more like connections and definitely avoids
this double release.
In the future it might be worth making applets have their own flags like
connections to carry their own state regardless of the stream interface's
state, especially when dealing with connection reuse.
No backport is needed since this issue was caused by the rearchitecture
in 1.6.
It's dangerous to call this on internal state error, because it risks
to perform a double-free. This can only happen when a state is not
handled. Note that the switch/case currently doesn't offer any option
for missed states since they're all declared. Better fix this anyway.
The fix was tested by commenting out some entries in the switch/case.
Due to the code inherited from the early CLI mode with the non-interactive
code, the SHUTR status was only considered while waiting for a request,
which prevents the connection from properly being closed during a dump,
and the connection used to remain established. This issue didn't happen
in 1.5 because while this part was missed, the resynchronization performed
in process_session() would detect the situation and handle the cleanup.
No backport is needed.
If an error happens during a dump on the CLI, an explicit call to
cli_release_handler() is performed. This is not needed anymore since
we introduced ->release() in the applet which is called upon error.
Let's remove this confusing call which can even be risky in some
situations.
If an applet tries to write to a closed connection, it hangs forever.
This results in some "get map" commands on the CLI to leave orphaned
connections alive.
Now the applet wakeup function detects that the applet still wants to
write while the channel is closed for reads, which is the equivalent
to the common "broken pipe" situation. In this case, an error is
reported on the stream interface, just as it happens with connections
trying to perform a send() in a similar situation.
With this fix the stats socket is properly released.
This function is a callback made only for calls from the applet handler.
Rename it to remove confusion. It's currently called from the Lua code
but that's not correct, we should call the notify and update functions
instead otherwise it will not enable the applet again.
This one is not needed anymore as what it used to do is either
completely covered by the new stream_int_notify() function, or undesired
and inherited from the past as a side effect of introducing the
connections.
This update is theorically never called since it's assigned only when
nothing is connected to the stream interface. However a test has been
added to si_update() to stay safe if some foreign code decides to call
si_update() in unsafe situations.
The code to report completion after a connection update or an applet update
was almost the same since applets stole it from the connection. But the
differences made them hard to maintain and prevented the creation of new
functions doing only one part of the work.
This patch replaces the common code from the si_conn_wake_cb() and
si_applet_wake_cb() with a single call to stream_int_notify() which only
notifies the stream (si+channels+task) from the outside.
No functional change was made beyond this.
stream_int_notify() was taken from the common part between si_conn_wake_cb()
and si_applet_done(). It is designed to report activity to a stream from
outside its handler. It'll generally be used by lower layers to report I/O
completion but may also be used by remote streams if the buffer processing
is shared.
The condition to release the SI_FL_WAIT_ROOM flag was abnormally
complicated because it was inherited from 6 years ago before we used
to check for the buffer's emptiness. The CF_READ_PARTIAL flag had to be
removed, and the complex test was replaced with a simpler one checking
if *some* data were moved out or not.
The reason behind this change is to have a condition compatible with
both connections and applets, as applets currently don't work very
well in this area. Specifically, some optimizations on the applet
side cause them not to release the flag above until the buffer is
empty, which may prevent applets from taking together (eg: peers
over large haproxy buffers and small kernel buffers).
