This commit introduces support for the "http-after-res" action in
hlua, enabling the invocation of a Lua function in a
"http-after-response" rule. With this enhancement, a Lua action can be
registered using the "http-after-res" action type:
core.register_action('myaction', {'http-after-res'}, myaction)
A new "lua.myaction" is created and can be invoked in a
"http-after-response" rule:
http-after-response lua.myaction
This addition provides greater flexibility and extensibility in
handling post-response actions using Lua.
This commit depends on:
- 4457783 ("MINOR: http_ana: position the FINAL flag for http_after_res execution")
Signed-off-by: Sébastien Gross <sgross@haproxy.com>
"converter" was used in place of "action" as a result of a copy-paste
error probably.
Also, rephrasing the "actions" keyword explanation to prevent confusion
between action name (which is the name of new action about to be created)
and action facilities where we want to expose the new action.
This could be backported to every stable versions.
Since f034139bc0 ("MINOR: lua: Allow reading "proc." scoped vars from
LUA core."), a new Sphinx warning is emitted when generating the lua doc:
"WARNING: Field list ends without a blank line; unexpected unindent."
This is due to a missing space after the line break continuation, sphinx
parser is very restrictive unfortunately!
Suppressing the warning and fixing the html output at the same time by
adding the missing space.
This adds the "core.get_var()" method allow the reading
of "proc." scoped variables outside of TXN or HTTP/TCPApplet.
Fixes: #2212
Signed-off-by: Daan van Gorkum <djvg@djvg.net>
As the example/lua/mailers.lua script does its best to mimic the c-mailer
implementation, it should support the "timeout mail" directive as well.
This could be backported in 2.8.
Despite the doc not mentionning it, core.{proxies,frontends,backends}
methods are also available from init context.
(through core.register_init() functions)
Updating the documentation to reflect this possibility.
Adding a new lua class: Queue.
This class provides a generic FIFO storage mechanism that may be shared
between multiple lua contexts to easily pass data between them, as stock
Lua doesn't provide easy methods for passing data between multiple
coroutines.
New Queue object may be obtained using core.queue()
(it works like core.concat() for a concat Class)
Lua documentation was updated (including some usage examples)
Proxy mailers, which are configured using "email-alert" directives
in proxy sections from the configuration, are now being exposed
directly in lua thanks to the proxy:get_mailers() method which
returns a class containing the various mailers settings if email
alerts are configured for the given proxy (else nil is returned).
Both the class and the proxy method were marked as LEGACY since this
feature relies on mailers configuration, and the goal here is to provide
the last missing bits of information to lua scripts in order to make
them capable of sending email alerts instead of relying on the soon-to-
be deprecated mailers implementation based on checks (see src/mailers.c)
Lua documentation was updated accordingly.
Exposing a new hlua function, available from body or init contexts, that
forcefully disables the sending of email alerts even if the mailers are
defined in haproxy configuration.
This will help for sending email directly from lua.
(prevent legacy email sending from intefering with lua)
Exposing SERVER_CHECK event through the lua API.
New lua class named ServerEventCheck was added to provide additional
data for SERVER_CHECK event.
Lua documentation was updated accordingly.
Server.get_pend_conn: number of pending connections to the server
Server.get_cur_sess: number of current sessions handled by the server
Lua documentation was updated accordingly.
'when' optional argument is provided to lua event handlers.
It is an integer representing the number of seconds elapsed since Epoch
and may be used in conjunction with lua `os.date()` function to provide
a custom format string.
Now that event_hdl api is properly implemented in hlua, we may add the
per-server event subscription in addition to the global event
subscription.
Per-server subscription allows to be notified for events related to
single server. It is useful to track a server UP/DOWN and DEL events.
It works exactly like core.event_sub() except that the subscription
will be performed within the server dedicated subscription list instead
of the global one.
The callback function will only be called for server events affecting
the server from which the subscription was performed.
Regarding the implementation, it is pretty trivial at this point, we add
more doc than code this time.
Usage examples have been added to the (lua) documentation.
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.
When building html documentation from doc/lua-api/index.rst, sphinx
complains about some unexpected indentations:
"doc/lua-api/index.rst:3221: WARNING: Unexpected indentation"
Silencing them without altering the original output format.
When building html documentation from doc/lua-api/index.rst, sphinx
complains about some literal blocks ending without a blank line:
"doc/lua-api/index.rst:534: WARNING: Literal block ends without a blank line; unexpected unindent."
Adding the missing blank lines to make sphinx happy
core.register_task(function) may now take up to 4 additional arguments
that will be passed as-is to the task function.
This could be convenient to spawn sub-tasks from existing functions
supporting core.register_task() without the need to use global
variables to pass some context to the newly created task function.
The new prototype is:
core.register_task(function[, arg1[, arg2[, ...[, arg4]]]])
Implementation remains backward-compatible with existing scripts.
Server revision ID was recently added to haproxy with 61e3894
("MINOR: server: add srv->rid (revision id) value")
Let's add it to the hlua server class.
Since ("MINOR: hlua_fcn: alternative to old proxy and server attributes"):
- s->name(), s->puid() are superseded by s->get_name() and s->get_puid()
- px->name(), px->uuid() are superseded by px->get_name() and
px->get_uuid()
And considering this is now the proper way to retrieve proxy name/uuid
and server name/puid from lua:
We're now removing such legacy attributes, but for retro-compatibility
purposes we will be emulating them and warning the user for some time
before completely dropping their support.
To do this, we first remove old legacy code.
Then we move server and proxy methods out of the metatable to allow
direct elements access without systematically involving the "__index"
metamethod.
This allows us to involve the "__index" metamethod only when the requested
key is missing from the table.
Then we define relevant hlua_proxy_index and hlua_server_index functions
that will be used as the "__index" metamethod to respectively handle
"name, uuid" (proxy) or "name, puid" (server) keys, in which case we
warn the user about the need to use the new getter function instead the
legacy attribute (to prepare for the potential upcoming removal), and we
call the getter function to return the value as if the getter function
was directly called from the script.
Note: Using the legacy variables instead of the getter functions results
in a slight overhead due to the "__index" metamethod indirection, thus
it is recommended to switch to the getter functions right away.
With this commit we're also adding a deprecation notice about legacy
attributes.
This patch adds new lua methods:
- "Proxy.get_uuid()"
- "Proxy.get_name()"
- "Server.get_puid()"
- "Server.get_name()"
These methods will be equivalent to their old analog Proxy.{uuid,name}
and Server.{puid,name} attributes, but this will be the new preferred
way to fetch such infos as it duplicates memory only when necessary and
thus reduce the overall lua Server/Proxy objects memory footprint.
Legacy attributes (now superseded by the explicit getters) are expected
to be removed some day.
Co-authored-by: Aurelien DARRAGON <adarragon@haproxy.com>
Link to lua toolbox was dead (project has been deprecated).
Adding a legacy link to get old toolbox source code as well as
a link to luarocks that seems to have superseded it.
Add the ability to set a "server timeout" on the httpclient with either
the httpclient_set_timeout() API or the timeout argument in a request.
Issue #1470.
The 'dst' optionnal field on a httpclient request can be used to set an
alternative server address in the haproxy address format. Which means it
could be use with unix@, ipv6@ etc.
Should fix issue #1471.
In HTTP, when a lua action is evaluated, a reply object can be used to send
a response to the client and interrupt the transaction. This reply object is
converted into HTX and is limited to the response channel buffer. Its size,
once converted, cannot exceed the buffer size. There is no streaming at this
stage. However, this limitation was not documented.
Note that, for now, there is no easy way to know if the reply will fit or
not int the response channel buffer. Thus the reply must be reasonably
small. Otherwise a 500-Internal-Error message is returned.
This patch is related to the issue #1447. It may be backported as far as
2.2.
When setting variables, there are currently two variants, one which will
always create the variable, and another one, "ifexist", which will only
create or update a variable if a similarly named variable in any scope
already existed before.
The goal was to limit the risk of injecting random names in the proc
scope, but it was achieved by making use of the somewhat limited name
indexing model, which explains the scope-agnostic restriction.
With this change, we're moving the check downwards in the chain, at the
variable level, and only variables under the scope "proc" will be subject
to the restriction. A new set of VF_* flags was added to adjust how
variables are set, and VF_UPDATEONLY is used to mention this restriction.
In this exact state of affairs, this is not completely exact, as if a
similar name was not known in any scope, the variable will continue to
be rejected like before, but this will change soon.
