Not all hlua "time" variables use the same time logic.
hlua->wake_time relies on ticks since its meant to be used in conjunction
with task scheduling. Thus, it should be stored as a signed int and
manipulated using the tick api.
Adding a few comments about that to prevent mixups with hlua internal
timer api which doesn't rely on the ticks api.
For non yieldable lua handlers (converters, fetches or yield
incompatible lua functions), current timeout detection relies on now_ms
thread local variable.
But within non-yieldable contexts, now_ms won't be updated if not by us
(because we're momentarily stuck in lua context so we won't
re-enter the polling loop, which is responsible for clock updates).
To circumvent this, clock_update_date(0, 1) was manually performed right
before now_ms is being read for the timeout checks.
But this fails to work consistently, because if no other concurrent
threads periodically run clock_update_global_date(), which do happen if
we're the only active thread (nbthread=1 or low traffic), our
clock_update_date() call won't reliably update our local now_ms variable
Moreover, clock_update_date() is not the right tool for this anyway, as
it was initially meant to be used from the polling context.
Using it could have negative impact on other threads relying on now_ms
to be stable. (because clock_update_date() performs global clock update
from time to time)
-> Introducing hlua multipurpose timer, which is internally based on
now_cpu_time_fast() that provides per-thread consistent clock readings.
Thanks to this new hlua timer API, hlua timeout logic is less error-prone
and more robust.
This allows the timeout detection to work as expected for both yieldable
and non-yieldable lua handlers.
This patch depends on commit "MINOR: clock: add now_cpu_time_fast() function"
While this could theorically be backported to all stable versions,
it is advisable to avoid backports unless we're confident enough
since it could cause slight behavior changes (timing related) in
existing setups.
Now that the event handler API is pretty mature, we can expose it in
the lua API.
Introducing the core.event_sub(<event_types>, <cb>) lua function that
takes an array of event types <event_types> as well as a callback
function <cb> as argument.
The function returns a subscription <sub> on success.
Subscription <sub> allows you to manage the subscription from anywhere
in the script.
To this day only the sub->unsub method is implemented.
The following event types are currently supported:
- "SERVER_ADD": when a server is added
- "SERVER_DEL": when a server is removed from haproxy
- "SERVER_DOWN": server states goes from up to down
- "SERVER_UP": server states goes from down to up
As for the <cb> function: it will be called when one of the registered
event types occur. The function will be called with 3 arguments:
cb(<event>,<data>,<sub>)
<event>: event type (string) that triggered the function.
(could be any of the types used in <event_types> when registering
the subscription)
<data>: data associated with the event (specific to each event family).
For "SERVER_" family events, server details such as server name/id/proxy
will be provided.
If the server still exists (not yet deleted), a reference to the live
server is provided to spare you from an additionnal lookup if you need
to have direct access to the server from lua.
<sub> refers to the subscription. In case you need to manage it from
within an event handler.
(It refers to the same subscription that the one returned from
core.event_sub())
Subscriptions are per-thread: the thread that will be handling the
event is the one who performed the subscription using
core.event_sub() function.
Each thread treats events sequentially, it means that if you have,
let's say SERVER_UP, then SERVER_DOWN in a short timelapse, then your
cb function will first be called with SERVER_UP, and once you're done
handling the event, your function will be called again with SERVER_DOWN.
This is to ensure event consitency when it comes to logging / triggering
logic from lua.
Your lua cb function may yield if needed, but you're pleased to process
the event as fast as possible to prevent the event queue from growing up
To prevent abuses, if the event queue for the current subscription goes
over 100 unconsumed events, the subscription will pause itself
automatically for as long as it takes for your handler to catch up.
This would lead to events being missed, so a warning will be emitted in
the logs to inform you about that. This is not something you want to let
happen too often, it may indicate that you subscribed to an event that
is occurring too frequently or/and that your callback function is too
slow to keep up the pace and you should review it.
If you want to do some parallel processing because your callback
functions are slow: you might want to create subtasks from lua using
core.register_task() from within your callback function to perform the
heavy job in a dedicated task and allow remaining events to be processed
more quickly.
Please check the lua documentation for more information.
This patch proposes to enumerate servers using internal HAProxy list.
Also, remove the flag SRV_F_NON_PURGEABLE which makes the server non
purgeable each time Lua uses the server.
Removing reg-tests/cli_delete_server_lua.vtc since this test is no
longer relevant (we don't set the SRV_F_NON_PURGEABLE flag anymore)
and we already have a more generic test:
reg-tests/server/cli_delete_server.vtc
Co-authored-by: Aurelien DARRAGON <adarragon@haproxy.com>
When HAproxy is loaded with a lot of frontends/backends (tested with 300k),
it is slow to start and it uses a lot of memory just for indexing backends
in the lua tables.
This patch uses the internal frontend/backend index of HAProxy in place of
lua table.
HAProxy startup is now quicker as each frontend/backend object is created
on demand and not at init.
This has to come with some cost: the execution of Lua will be a little bit
slower.
In bb581423b ("BUG/MEDIUM: httpclient/lua: crash when the lua task timeout
before the httpclient"), a new logic was implemented to make sure that
when a lua ctx destroyed, related httpclients are correctly destroyed too
to prevent a such httpclients from being resuscitated on a destroyed lua ctx.
This was implemented by adding a list of httpclients within the lua ctx,
and a new function, hlua_httpclient_destroy_all(), that is called under
hlua_ctx_destroy() and runs through the httpclients list in the lua context
to properly terminate them.
This was done with the assumption that no concurrent Lua garbage collection
cycles could occur on the same ressources, which seems OK since the "lua"
context is about to be freed and is not explicitly being used by other threads.
But when 'lua-load' is used, the main lua stack is shared between multiple
OS threads, which means that all lua ctx in the process are linked to the
same parent stack.
Yet it seems that lua GC, which can be triggered automatically under
lua_resume() or manually through lua_gc(), does not limit itself to the
"coroutine" stack (the stack referenced in lua->T) when performing the cleanup,
but is able to perform some cleanup on the main stack plus coroutines stacks
that were created under the same main stack (via lua_newthread()) as well.
This can be explained by the fact that lua_newthread() coroutines are not meant
to be thread-safe by design.
Source: http://lua-users.org/lists/lua-l/2011-07/msg00072.html (lua co-author)
It did not cause other issues so far because most of the time when using
'lua-load', the global lua lock is taken when performing critical operations
that are known to interfere with the main stack.
But here in hlua_httpclient_destroy_all(), we don't run under the global lock.
Now that we properly understand the issue, the fix is pretty trivial:
We could simply guard the hlua_httpclient_destroy_all() under the global
lua lock, this would work but it could increase the contention over the
global lock.
Instead, we switched 'lua->hc_list' which was introduced with bb581423b
from simple list to mt_list so that concurrent accesses between
hlua_httpclient_destroy_all and hlua_httpclient_gc() are properly handled.
The issue was reported by @Mark11122 on Github #2037.
This must be backported with bb581423b ("BUG/MEDIUM: httpclient/lua: crash
when the lua task timeout before the httpclient") as far as 2.5.
When the lua task finished before the httpclient that are associated to
it, there is a risk that the httpclient try to task_wakeup() the lua
task which does not exist anymore.
To fix this issue the httpclient used in a lua task are stored in a
list, and the httpclient are destroyed at the end of the lua task.
Must be backported in 2.5 and 2.6.
The CertCache.set() function allows to update an SSL certificate file
stored in the memory of the HAProxy process. This function does the same
as "set ssl cert" + "commit ssl cert" over the CLI.
This could be used to update the crt and key, as well as the OCSP, the
SCTL, and the OSCP issuer.
The implementation does yield every 10 ckch instances, the same way the
"commit ssl cert" do.
With this feature the lua implementation of the httpclient is now able
to stream a payload larger than an haproxy buffer.
The hlua_httpclient_send() function is now split into:
hlua_httpclient_send() which initiate the httpclient and parse the lua
parameters
hlua_httpclient_snd_yield() which will send the request and be called
again to stream the request if the body is larger than an haproxy buffer
hlua_httpclient_rcv_yield() which will receive the response and store it
in the lua buffer.
Flags used to set the execution context of a lua txn are used as an enum. It is
not uncommon but there are few flags otherwise. So to remove ambiguities, a
comment and a _NONE value are added to have a clear definition of supported
values.
This patch should fix the issue #1429. No backport needed.
No need to include the full tree management code, type files only
need the definitions. Doing so reduces the whole code size by around
3.6% and the build time is down to just 6s.
This commit provides an hlua_httpclient object which is a bridge between
the httpclient and the lua API.
The HTTPClient is callable in lua this way:
local httpclient = core.httpclient()
local response = httpclient:get("http://127.0.0.1:9000/?s=9999")
core.Debug("Status: ".. res.status .. ", Reason : " .. res.reason .. ", Len:" .. string.len(res.body) .. "\n")
The resulting response object will provide a "status" field which
contains the status code, a "reason" string which contains the reason
string, and a "body" field which contains the response body.
The implementation uses the httpclient callback to wake up the lua task
which yield each time it pushes some data. The httpclient works in the
same thread as the lua task.
This new class exposes methods to manipulate HTTP messages from a filter
written in lua. Like for the HTTP class, there is a bunch of methods to
manipulate the message headers. But there are also methods to manipulate the
message payload. This part is similar to what is available in the Channel
class. Thus the payload can be duplicated, erased, modified or
forwarded. For now, only DATA blocks can be retrieved and modified because
the current API is limited. No HTTPMessage method is able to yield. Those
manipulating the headers are always called on messages containing all the
headers, so there is no reason to yield. Those manipulating the payload are
called from the http_payload filters callback function where yielding is
forbidden.
When an HTTPMessage object is instantiated, the underlying Channel object
can be retrieved via the ".channel" field.
For now this class is not used because the HTTP filtering is not supported
yet. It will be the purpose of another commit.
There is no documentation for now.
A lua TXN can be created when a sample fetch, an action or a filter callback
function is executed. A flag is now used to track the execute context.
Respectively, HLUA_TXN_SMP_CTX, HLUA_TXN_ACT_CTX and HLUA_TXN_FLT_CTX. The
filter flag is not used for now.
When a script is executed, a flag is used to allow it to yield. An error is
returned if a lua function yield, explicitly or not. But there is no way to
get this capability in C functions. So there is no way to choose to yield or
not depending on this capability.
To fill this gap, the flag HLUA_NOYIELD is introduced and added on the lua
context if the current script execution is not authorized to yield. Macros
to set, clear and test this flags are also added.
This feature will be usefull to fix some bugs in lua actions execution.
The goal is to allow execution of one main lua state per thread.
The array introduces storage of one reference per thread, because each
lua state can have different reference id for a same function. A function
returns the preferred state id according to configuration and current
thread id.
The goal is to allow execution of one main lua state per thread.
"state_from" is a pointer to the parent lua state. "state_id"
is the index of the parent state id in the reference lua states
array. "state_id" is better because the lock is a "== 0" test
which is quick than pointer comparison. In other way, the state_id
index could index other things the the Lua state concerned. I
think to the function references.
The goal is to allow execution of one main lua state per thread.
This function will initialize the struct with other things than 0.
With this function helper, the initialization is centralized and
it prevents mistakes. This patch also keeps a reference to each
declared function in a list. It will be useful in next patches to
control consistency of declared references.
The goal is to allow execution of one main lua state per thread.
The function hlua_ctx_init() now gets the original lua state from
its caller. This allows the initialisation of lua_thread (coroutines)
from any master lua state.
The parent lua state is stored in the hlua struct.
This patch is a temporary transition, it will be modified later.
The goal is to allow execution of one main lua state per thread.
Because this struct will be filled after the configuration parser, we
cannot copy the content. The actual state of the Haproxy code doesn't
justify this change, it is an update preparing next steps.
There are list definitions everywhere in the code, let's drop the need
for including list-t.h to declare them. The rest of the list manipulation
is huge however and not needed everywhere so using the list walking macros
still requires to include list.h.
This patch fixes all the leftovers from the include cleanup campaign. There
were not that many (~400 entries in ~150 files) but it was definitely worth
doing it as it revealed a few duplicates.
extern struct dict server_name_dict was moved from the type file to the
main file. A handful of inlined functions were moved at the bottom of
the file. Call places were updated to use server-t.h when relevant, or
to simply drop the entry when not needed.
This one is particularly difficult to split because it provides all the
functions used to manipulate a proxy state and to retrieve names or IDs
for error reporting, and as such, it was included in 73 files (down to
68 after cleanup). It would deserve a small cleanup though the cut points
are not obvious at the moment given the number of structs involved in
the struct proxy itself.
It was moved without any change, however many callers didn't need it at
all. This was a consequence of the split of proto_http.c into several
parts that resulted in many locations to still reference it.
The stktable_types[] array declaration was moved to the main file as
it had nothing to do in the types. A few declarations were reordered
in the types file so that defines were before the structs. Thread-t
was added since there are a few __decl_thread(). The loss of peers.h
revealed that cfgparse-listen needed it.
