The aim is to rassemble all scheduler information related to the current
thread. It simply points to task_per_thread[tid] without having to perform
the operation at each time. We save around 1.2 kB of code on performance
sensitive paths and increase the request rate by almost 1%.
Now that we can wake up a remote thread's tasklet, it's way more
interesting to use a tasklet than a task in the accept queue, as it
will avoid passing through all the scheduler. Just doing this increases
the accept rate by about 4%, overall recovering the slight loss
introduced by the tasklet change. In addition it makes sure that
even a heavily loaded scheduler (e.g. many very fast checks) will
not delay a connection accept.
Change the tasklet code so that the tasklet list is now a mt_list.
That means that tasklet now do have an associated tid, for the thread it
is expected to run on, and any thread can now call tasklet_wakeup() for
that tasklet.
One can change the associated tid with tasklet_set_tid().
Instead of using the same type for regular linked lists and "autolocked"
linked lists, use a separate type, "struct mt_list", for the autolocked one,
and introduce a set of macros, similar to the LIST_* macros, with the
MT_ prefix.
When we use the same entry for both regular list and autolocked list, as
is done for the "list" field in struct connection, we know have to explicitely
cast it to struct mt_list when using MT_ macros.
The FCGI application handles all the configuration parameters used to format
requests sent to an application. The configuration of an application is grouped
in a dedicated section (fcgi-app <name>) and referenced in a backend to be used
(use-fcgi-app <name>). To be valid, a FCGI application must at least define a
document root. But it is also possible to set the default index, a regex to
split the script name and the path-info from the request URI, parameters to set
or unset... In addition, this patch also adds a FCGI filter, responsible for
all processing on a stream.
Most of times, when a keyword is added in proxy section or on the server line,
we need to have a post-parser callback to check the config validity for the
proxy or the server which uses this keyword.
It is possible to register a global post-parser callback. But all these
callbacks need to loop on the proxies and servers to do their job. It is neither
handy nor efficient. Instead, it is now possible to register per-proxy and
per-server post-check callbacks.
Most of times, when any allocation is done during configuration parsing because
of a new keyword in proxy section or on the server line, we must add a call in
the deinit() function to release allocated ressources. It is now possible to
register a post-deinit callback because, at this stage, the proxies and the
servers are already releases.
Now, it is possible to register deinit callbacks per-proxy or per-server. These
callbacks will be called for each proxy and server before releasing them.
It is now possible to export stats using the JSON format from the HTTP stats
page. Like for the CSV export, to export stats in JSON, you must add the option
";json" on the stats URL. It is also possible to dump the JSON schema with the
option ";json-schema". Corresponding Links have been added on the HTML page.
This patch fixes the issue #263.
This adds two extra fields to the stats, one for the current number of idle
connections and one for the configured limit. A tooltip link now appears on
the HTML page to show these values in front of the active connection values.
This should be backported to 2.0 and 1.9 as it's the only way to monitor
the idle connections behaviour.
There's currently a big ambiguity on our use of POLLHUP because we
currently map POLLHUP and POLLRDHUP to FD_POLL_HUP. The first one
indicates a close in *both* directions while the second one indicates
a unidirectional close. Since we don't know from the resulting flag
we always have to read when reported. Furthermore kqueue only reports
unidirectional responses which are mapped to FD_POLL_HUP as well, and
their write closes are mapped to a general error.
We could add a new FD_POLL_RDHUP flag to improve the mapping, or
switch only to the POLL* flags, but that further complicates the
portability for operating systems like FreeBSD which do not have
POLLRDHUP but have its semantics.
Let's instead directly use the per-direction flag values we already
have, and it will be a first step in the direction of finer states.
Thus we introduce an ERR and a SHUT status for each direction, that
the pollers will be able to compute and pass to fd_update_events().
It's worth noting that FD_EV_STATUS already sees the two new flags,
but they are harmless since used only by fd_{recv,send}_state() which
are never called. Thus in its current state this patch must be totally
transparent.
Now that we don't have to update FD_EV_POLLED_* at the same time as
FD_EV_ACTIVE_*, we don't need to use a CAS anymore, a bit-test-and-set
operation is enough. Doing so reduces the code size by a bit more than
1 kB. One function was special, fd_done_recv(), whose comments and doc
were inaccurate for the part related to the lack of polling.
Since commit 7ac0e35f2 in 1.9-dev1 ("MAJOR: fd: compute the new fd polling
state out of the fd lock") we've started to update the FD POLLED bit a
bit more aggressively. Lately with the removal of the FD cache, this bit
is always equal to the ACTIVE bit. There's no point continuing to watch
it and update it anymore, all it does is create confusion and complicate
the code. One interesting side effect is that it now becomes visible that
all fd_*_{send,recv}() operations systematically call updt_fd_polling(),
except fd_cant_recv()/fd_cant_send() which never saw it change.
Now by prefixing a log server with "ring@<name>" it's possible to send
the logs to a ring buffer. One nice thing is that it allows multiple
sessions to consult the logs in real time in parallel over the CLI, and
without requiring file system access. At the moment, ring0 is created as
a default sink for tracing purposes and is available. No option is
provided to create new rings though this is trivial to add to the global
section.
Instead of detecting an AF_UNSPEC address family for a log server and
to deduce a file descriptor, let's create a target type field and
explicitly mention that the socket is of type FD.
The purpose is to be able to remember that initialization was already
done for a file descriptor. This will allow to get rid of some dirty
hacks performed in the logs or fd sinks where the init state of the
fd has to be guessed.
The "cache" entry was still present in the fdtab struct and it was
reported in "show sess". Removing it broke the cache-line alignment
on 64-bit machines which is important for threads, so it was fixed
by adding an attribute(aligned()) when threads are in use. Doing it
only in this case allows 32-bit thread-less platforms to see the
struct fit into 32 bytes.
Now it is possible for a reader to subscribe and wait for new events
sent to a ring buffer. When new events are written to a ring buffer,
the applets that are subscribed are woken up to display new events.
For now we only support this with the CLI applet called by "show events"
since the I/O handler is indeed a CLI I/O handler. But it's not
complicated to add other mechanisms to consume events and forward them
to external log servers for example. The wait mode is enabled by adding
"-w" after "show events <sink>". An extra "-n" was added to directly
seek to new events only.
Some CLI parsers are currently abusing the CLI context types such as
pointers to stuff longs into them by lack of room. But the context is
80 bytes while cli is only 48, thus there's some room left. This patch
adds a list element and two size_t usable as various offsets. The list
element is initialized.
The detail level initially based on syslog levels is not used, while
something related is missing, trace verbosity, to indicate whether or
not we want to call the decoding callback and what level of decoding
we want (raw captures etc). Let's change the field to "verbosity" for
this. A verbosity of zero means that the decoding callback is not
called, and all other levels are handled by this callback and are
source-specific. The source is now prompted to list the levels that
are proposed to the user. When the source doesn't define anything,
"quiet" and "default" are available.
Working on adding traces to mux-h2 revealed that the function names are
manually copied a lot in developer traces. The reason is that they are
not preprocessor macros and as such cannot be concatenated. Let's
slightly adjust the trace() function call to take a function name just
after the file:line argument. This argument is only added for the
TRACE_DEVEL and 3 new TRACE_ENTER, TRACE_LEAVE, and TRACE_POINT macros
and left NULL for others. This way the function name is only reported
for traces aimed at the developers. The pretty-print callback was also
extended to benefit from this. This will also significantly shrink the
data segment as the "entering" and "leaving" strings will now be merged.
One technical point worth mentioning is that the function name is *not*
passed as an ist to the inline function because it's not considered as
a builtin constant by the compiler, and would lead to strlen() being
run on it from all call places before calling the inline function. Thus
instead we pass the const char * (that the compiler knows where to find)
and it's the __trace() function that converts it to an ist for internal
consumption and for the pretty-print callback. Doing this avoids losing
5-10% peak performance.
The "payload" trace level was ambigous because its initial purpose was
to be able to dump received data. But it doesn't make sense to force to
report data transfers just to be able to report state changes. For
example, all snd_buf()/rcv_buf() operations coming from the application
layer should be tagged at this level. So here we move this payload level
above the state transitions and rename it to avoid the ambiguity making
one think it's only about request/response payload. Now it clearly is
about any data transfer and is thus just below the developer level. The
help messages on the CLI and the doc were slightly reworded to help
remove this ambiguity.
Save the authority TLV in a PROXYv2 header from the client connection,
if present, and make it available as fc_pp_authority.
The fetch can be used, for example, to set the SNI for a backend TLS
connection.
It becomes apparent that most traces will use a single trace pretty
print callback, so let's allow the trace source to declare a default
one so that it can be omitted from trace calls, and will be used if
no other one is specified.
The principle is that when emitting a message, if some dropped events
were logged, we first attempt to report this counter before going
further. This is done under an exclusive lock while all logs are
produced under a shared lock. This ensures that the dropped line is
accurately reported and doesn't accidently arrive after a later
event.
This now provides sink_new_buf() which allocates a ring buffer. One such
ring ("buf0") of 1 MB is created already, and may be used by sink_write().
The sink's creation should probably be moved somewhere else later.
Our circular buffers are well suited for being used as ring buffers for
not-so-structured data. The machanism here consists in making room in a
buffer before inserting a new record which is prefixed by its size, and
looking up next record based on the previous one's offset and size. We
can have up to 255 consumers watching for data (dump in progress, tail)
which guarantee that entrees are not recycled while they're being dumped.
The complete representation is described in the header file. For now only
ring_new(), ring_resize() and ring_free() are created.
Currently both logs and event sinks may use a file descriptor to
atomically emit some output contents. The two may use the same FD though
nothing is done to make sure they use the same lock. Also there is quite
some redundancy between the two. Better make a specific function to send
a fragmented message to a file descriptor which will take care of the
locking via the fd's lock. The function is also able to truncate a
message and to enforce addition of a trailing LF when building the
output message.
I forgot to fix this one before pushing, despite my tests. lockon_ptr is
only used to compare pointers, it doesn't need to point to a writable
location. Without threads the atomic store is turned into an assignment
and rightfully complains.
Given that we can pass typed arguments to the trace() function, let's
add provisions for tracking them. They are source-specific so we need
to let the source fill their name and description. Only those with a
non-null name will be proposed.
With a few macros it's possible for a trace source to commit to only
using a certain type for a given argument (or set of). This will be
particularly useful to let the trace subsystem retrieve some precious
information such as a connection, session, listener, source address or
so, and enable/disable filtering and/or locking.
The principle of this subsystem will be to support taking live traces
at various places in the code with conditional triggers, filters, and
ability to lock on some elements. The traces will support typed events
and will be sent into sinks made of ring buffers, file descriptors or
remote servers.
This is the most basic type of sink. It pre-registers "stdout" and
"stderr", and is able to use writev() on them. The writev() operation
is locked to avoid mixing outputs. It's likely that the registration
should move somewhere else to take into account the fact that stdout
and stderr are still opened or are closed.
The principle will be to be able to dispatch events to various destinations
called "sinks". This is already done in part in logs where log servers can
be either a UDP socket or a file descriptor. This will be needed with the
new trace subsystem where we may also want to add ring buffers. And it turns
out that all such destinations make sense at all places. Logs may need to be
sent to a TCP server via a ring buffer, or consulted from the CLI. Trace
events may need to be sent to stdout/stderr as well as to remote log servers.
This patch creates a new structure "sink" aiming at addressing these similar
needs. The goal is to merge together what is common to all of them, such as
the output format, the dropped events count, etc, and also keep separately
the target identification (network address, file descriptor). Provisions
were made to have a "waiter" on the sink. For a TCP log server it will be
the task to wake up after writing to the log buffer. For a ring buffer, it
could be the list of watchers on the CLI running a "tail" operation and
waiting for new events. A lock was also placed in the struct since many
operations will require some locking, including the FD ones. The output
formats covers those in use by logs and two extra ones prepending the ISO
time in front of the message (convenient for stdio/buffer).
For now only the generic infrastructure is present, no type-specific
output is implemented. There's the sink_write() function which prepares
and formats a message to be sent, trying hard to avoid copies and only
using pointer manipulation, where the type-specific code just has to be
added. Dropped messages are already counted (for now 100% drop). The
message is put into an iovec array as it will be trivial to use with
file descriptors and sockets.
Right now we used to have extremely inconsistent states to report output,
one is CLI_ST_PRINT which prints constant message cli->msg with the
assigned severity, and CLI_ST_PRINT_FREE which prints dynamically
allocated cli->err with severity LOG_ERR, and nothing in between,
eventhough it's useful to be able to report dynamically allocated
messages as well as constant error messages.
This patch adds two extra states, which are not particularly well named
given the constraints imposed by existing ones. One is CLI_ST_PRINT_ERR
which prints a constant error message. The other one is CLI_ST_PRINT_DYN
which prints a dynamically allocated message. By doing so we maintain
the compatibility with current code.
It is important to keep in mind that we cannot pre-initialize pointers
and automatically detect what message type it is based on the assigned
fields, because the CLI's context is in a union shared with all other
users, thus unused fields contain anything upon return. This is why we
have no choice but using 4 states. Keeping the two fields <msg> and
<err> remains useful because one is const and not the other one, and
this catches may copy-paste mistakes. It's just that <err> is pretty
confusing here, it should be renamed.
The CPU time accounting field called "cpu_time" is used only by tasks
and not tasklets, yet it used to be stored into the TASK_COMMON part,
which doesn't make sense and wastes tasklet memory. In addition, moving
it to tasks also helps better group the various parts in cache lines.
In stream_set_backend(), if we have a TCP stream, and we want to upgrade it
to H2 instead of attempting ot reuse the stream, just destroy the
conn_stream, make sure we don't log anything about the stream, and pretend
we failed setting the backend, so that the stream will get destroyed.
New streams will then be created by the mux, as if the connection just
happened.
This fixes a crash when upgrading from TCP to H2, as the H2 mux totally
ignored the conn_stream provided by the upgrade, as reported in github
issue #196.
This should be backported to 2.0.
Now that the architecture was changed so that attempts to receive/send data
always come from the upper layers, instead of them only trying to do so when
the lower layer let them know they could try, we can finally get rid of the
fd cache. We don't really need it anymore, and removing it gives us a small
performance boost.
A problem involving server slowstart was reported by @max2k1 in issue #197.
The problem is that pendconn_grab_from_px() takes the proxy lock while
already under the server's lock while process_srv_queue() first takes the
proxy's lock then the server's lock.
While the latter seems more natural, it is fundamentally incompatible with
mayn other operations performed on servers, namely state change propagation,
where the proxy is only known after the server and cannot be locked around
the servers. Howwever reversing the lock in process_srv_queue() is trivial
and only the few functions related to dynamic cookies need to be adjusted
for this so that the proxy's lock is taken for each server operation. This
is possible because the proxy's server list is built once at boot time and
remains stable. So this is what this patch does.
The comments in the proxy and server structs were updated to mention this
rule that the server's lock may not be taken under the proxy's lock but
may enclose it.
Another approach could consist in using a second lock for the proxy's queue
which would be different from the regular proxy's lock, but given that the
operations above are rare and operate on small servers list, there is no
reason for overdesigning a solution.
This fix was successfully tested with 10000 servers in a backend where
adjusting the dyncookies in loops over the CLI didn't have a measurable
impact on the traffic.
The only workaround without the fix is to disable any occurrence of
"slowstart" on server lines, or to disable threads using "nbthread 1".
This must be backported as far as 1.8.
When a lua action or a lua sample fetch is called, a lua transaction is
created. It is an entry in the stack containing the class TXN. Thanks to it, we
can know the direction (request or response) of the call. But, for some
functions, it is also necessary to know if the buffer is "HTTP ready" for the
given direction. "HTTP ready" means there is a valid HTTP message in the
channel's buffer. So, when a lua action or a lua sample fetch is called, the
flag HLUA_TXN_HTTP_RDY is set if it is appropriate.
There is no standard case for HTTP header names because, as stated in the
RFC7230, they are case-insensitive. So applications must handle them in a
case-insensitive manner. But some bogus applications erroneously rely on the
case used by most browsers. This problem becomes critical with HTTP/2
because all header names must be exchanged in lowercase. And HAProxy uses the
same convention. All header names are sent in lowercase to clients and servers,
regardless of the HTTP version.
This design choice is linked to the HTX implementation. So, for previous
versions (2.0 and 1.9), a workaround is to disable the HTX mode to fall
back to the legacy HTTP mode.
Since the legacy HTTP mode was removed, some users reported interoperability
issues because their application was not able anymore to handle HTTP/1 message
received from HAProxy. So, we've decided to add a way to change the case of some
headers before sending them. It is now possible to define a "mapping" between a
lowercase header name and a version supported by the bogus application. To do
so, you must use the global directives "h1-case-adjust" and
"h1-case-adjust-file". Then options "h1-case-adjust-bogus-client" and
"h1-case-adjust-bogus-server" may be used in proxy sections to enable the
conversion. See the configuration manual for more info.
Of course, our advice is to urgently upgrade these applications for
interoperability concerns and because they may be vulnerable to various types of
content smuggling attacks. But, if your are really forced to use an unmaintained
bogus application, you may use these directive, at your own risks.
If it is relevant, this feature may be backported to 2.0.
Dragan Dosen found that the listeners lock is not sufficient to protect
the listeners list when proxies are stopping because the listeners are
also unlinked from the protocol list, and under certain situations like
bombing with soft-stop signals or shutting down many frontends in parallel
from multiple CLI connections, it could be possible to provoke multiple
instances of delete_listener() to be called in parallel for different
listeners, thus corrupting the protocol lists.
Such operations are pretty rare, they are performed once per proxy upon
startup and once per proxy on shut down. Thus there is no point trying
to optimize anything and we can use a global lock to protect the protocol
lists during these manipulations.
This fix (or a variant) will have to be backported as far as 1.8.
The purpose will be to store the target address there and not to
allocate a connection just for this anymore. For now it's only placed
in the struct, a few fields were moved to plug some holes, and the
entry is freed on release (never allocated yet for now). This must
have no impact. Note that in order to fit, the store_count which
previously was an int was turned into a short, which is way more
than enough given that the hard-coded limit is 8.
Now addresses are dynamically allocated when needed. Each connection is
created with src=dst=NULL, these entries are allocated on the fly, and
released when the connection is released.
At the moment we're facing difficulties with connection reuse based on
the fact that connections may be allocated very early only to set a
target address in transparent mode. With the imminent removal of the
legacy mode, the connection reuse by a same stream will not exist
anymore and all this awful complexity is not justified anymore. However
we still need to be able to assign addresses somewhere.
Thus instead of allocating a connection, we'll only place addresses where
needed in the stream during operations. But this takes quite some room
(typically 128 bytes). This is a nice opportunity for cleaning all this
up and dynamically allocatating the addresses fields, which will result
in actually saving memory from connection structs since most of the time
the client's "to" address is not used and the server's "from" is not used
either, thus saving ~256 bytes per end-to-end connection.
For now these new "src" and "dst" pointers point to addr.from and addr.to.
This will allow us to smoothly update the whole code to use these pointers
prior to going further and switching them to pools.
The keywords req* and rsp* are now unsupported. So the corresponding lists are
now unused. It is safe to remove them from the structure proxy.
As a result, the code dealing with these rules in HTTP analyzers was also
removed.
It was announced for the 2.1. Following keywords are now unsupported:
* reqadd, reqallow, reqiallow, reqdel, reqidel, reqdeny, reqideny, reqpass,
reqipass, reqrep, reqirep reqtarpit, reqitarpit
* rspadd, rspdel, rspidel, rspdeny, rspideny, rsprep, rspirep
a fatal error is emitted if one of these keyword is found during the
configuraion parsing.
The option 'http-tunnel' is deprecated and it was only used in the legacy HTTP
mode. So this option is now totally ignored and a warning is emitted during
HAProxy startup if it is found in a configuration file.
