Tasklets may be woken up to run on the calling thread or by a specific thread
(the owner). But since we use a non-thread safe mechanism when the calling
thread is also the for the owner, there may sometimes be collisions when two
threads decide to wake the same tasklet up at the same time and one of them
is the owner.
This is more of a matter of usage than code, in that a tasklet usually is
designed to be woken up and executed on the calling thread only (most cases)
or on a specific thread. Thus it is a property of the tasklet itself as this
solely depends how the code is constructed around it.
This patch performs a small change to address this. By default tasklet_new()
creates a "local" tasklet, which will run on the calling thread, like in 2.0.
This is done by setting tl->tid to a negative value. If the caller wants the
tasklet to run exclusively on a specific thread, it just has to set tl->tid,
which is already what shared tasklet callers do anyway.
No backport is needed.
The use of ~(1 << tid) to compute the sleeping_mask in tasklet_wakeup()
will result in breakage above 32 threads, because (1<<31) = 0xFFFFFFFF8000000,
and upper values will lead to theorically undefined results, but practically
will wrap over 0x1 to 0x80000000 again and indicate wrong sleeping masks. It
seems that the main visible effect maybe extra latency on some threads or
short CPU loops on others.
No backport is needed.
In MT_LIST_BEHEAD(), explicitely set the next element of the prev to NULL,
instead of setting it to the prev of the next. If we only had one element,
then we'd set the next and the prev to the element itself, and thus it would
make the element appear to be outside any list.
A lot of our chunk-based functions are able to work on a buffer pointer
but not on an ist. Instead of duplicating all of them to also take an
ist as a source, let's have a macro to make a temporary dummy buffer
from an ist. This will only result in structure field manipulations
that the compiler will quickly figure to eliminate them with inline
functions, and in other cases it will just use 4 words in the stack
before calling a function, instead of performing intermediary
conversions.
The flag HTX_FL_PROXY_RESP is now set on responses generated by HAProxy,
excluding responses returned by applets and services. It is an informative flag
set by the applicative layer.
It currently is not possible to figure the exact haproxy version from a
core file for the sole reason that the version is stored into a const
string and as such ends up in the .text section that is not part of a
core file. By turning them into variables we move them to the data
section and they appear in core files. In order to help finding them,
we just prepend an extra variable in front of them and we're able to
immediately spot the version strings from a core file:
$ strings core | fgrep -A2 'HAProxy version'
HAProxy version follows
2.1-dev2-e0f48a-88
2019/10/15
(These are haproxy_version and haproxy_date respectively). This may be
backported to 2.0 since this part is not support to impact anything but
the developer's time spent debugging.
When raw data are copied or appended in a chunk, the result must not exceed the
chunk size but it can reach it. Unlike functions to copy or append a string,
there is no terminating null byte.
This patch must be backported as far as 1.8. Note in 1.8, the functions
chunk_cpy() and chunk_cat() don't exist.
Don't try to load the files containing the issuer and the OCSP response
each time we generate a SSL_CTX.
The .ocsp and the .issuer are now loaded in the struct
cert_key_and_chain only once and then loaded from this structure when
creating a SSL_CTX.
Don't try to load the file containing the sctl each time we generate a
SSL_CTX.
The .sctl is now loaded in the struct cert_key_and_chain only once and
then loaded from this structure when creating a SSL_CTX.
Note that this now make possible the use of sctl with multi-cert
bundles.
$ echo -e "set ssl cert certificate.pem <<\n$(cat certificate2.pem)\n" | \
socat stdio /var/run/haproxy.stat
Certificate updated!
The operation is locked at the ckch level with a HA_SPINLOCK_T which
prevents the ckch architecture (ckch_store, ckch_inst..) to be modified
at the same time. So you can't do a certificate update at the same time
from multiple CLI connections.
SNI trees are also locked with a HA_RWLOCK_T so reading operations are
locked only during a certificate update.
Bundles are supported but you need to update each file (.rsa|ecdsa|.dsa)
independently. If a file is used in the configuration as a bundle AND
as a unique certificate, both will be updated.
Bundles, directories and crt-list are supported, however filters in
crt-list are currently unsupported.
The code tries to allocate every SNIs and certificate instances first,
so it can rollback the operation if that was unsuccessful.
If you have too much instances of the certificate (at least 20000 in my
tests on my laptop), the function can take too much time and be killed
by the watchdog. This will be fixed later. Also with too much
certificates it's possible that socat exits before the end of the
generation without displaying a message, consider changing the socat
timeout in this case (-t2 for example).
The size of the certificate is currently limited by the maximum size of
a payload, that must fit in a buffer.
In order to allow the creation of sni_ctx in runtime, we need to split
the function to allow rollback.
We need to be able to allocate all sni_ctxs required before inserting
them in case we need to rollback if we didn't succeed the allocation.
The function was splitted in 2 parts.
The first one ckch_inst_add_cert_sni() allocates a struct sni_ctx, fill
it with the right data and insert it in the ckch_inst's list of sni_ctx.
The second will take every sni_ctx in the ckch_inst and insert them in
the bind_conf's sni tree.
struct ckch_inst represents an instance of a certificate (ckch_node)
used in a bind_conf. Every sni_ctx created for 1 ckch_node in a
bind_conf are linked in this structure.
This patch allocate the ckch_inst for each bind_conf and inserts the
sni_ctx in its linked list.
As using an mt_list for the tasklet list is costly, instead use a regular list,
but add an mt_list for tasklet woken up by other threads, to be run on the
current thread. At the beginning of process_runnable_tasks(), we just take
the new list, and merge it into the task_list.
This should give us performances comparable to before we started using a
mt_list, but allow us to use tasklet_wakeup() from other threads.
This macro atomically cuts the head of a list and returns the list
of elements as a detached list, meaning that they're all linked
together without any head. If the list was empty, NULL is returned.
Several times some users have expressed the non-intuitive aspect of some
of our stat/info metrics and suggested to add some help. This patch
replaces the char* arrays with an array of name_desc so that we now have
some reserved room to store a description with each stat or info field.
These descriptions are currently empty and not reported yet.
Now "show info" and "show stat" can parse "desc" as an output format
modifier that will be passed down the chain to add some descriptions
to the fields depending on the format in use. For now it is not
exploited.
This flag is used to decide to show the check box in front of a proxy
on the HTML stat page. It is always equal to STAT_ADMIN except when the
proxy has no backend capability (i.e. a pure frontend) or has no server,
in which case it's only used to avoid leaving an empty column at the
beginning of the table. Not only this is pretty useless, but it also
causes the columns not to align well when mixing multiple proxies with
or without servers.
Let's simply always use STAT_ADMIN and get rid of this flag.
We used to rely on some config flags defined in uri_auth.h set during
parsing, and another set of STAT_* flags defined in stats.h set at run
time, with a somewhat gray area between the two sets. This is confusing
in the stats code as both are called "flags" in various functions and
it's quite hard to know which one describes what.
This patch cleans this up by replacing all ST_* by a newly assigned
value from the STAT_* set so that we can now use unified flags to
describe both the configuration and the current state. There is no
functional change at all.
This flag was added in 1.4-rc1 by commit 329f74d463 ("[BUG] uri_auth: do
not attemp to convert uri_auth -> http-request more than once") to
address the case where two proxies inherit the stats settings from
the defaults instance, and the first one compiles the expression while
the second one uses it. In this case since they use the exact same
uri_auth pointer, only the first one should compile and the second one
must not fail the check. This was addressed by adding an ST_CONVDONE
flag indicating that the expression conversion was completed and didn't
need to be done again. But this is a hack and it becomes cumbersome in
the middle of the other flags which are all relevant to the stats
applet. Let's instead fix it by checking if we're dealing with an
alias of the defaults instance and refrain from compiling this twice.
This allows us to remove the ST_CONVDONE flag.
A typical config requiring this check is :
defaults
mode http
stats auth foo:bar
listen l1
bind :8080
listen l2
bind :8181
Without this (or previous) check it would cmoplain when checking l2's
validity since the rule was already built.
The function http_get_authority() may be used to parse a URI and looks for the
authority, between the scheme and the path. An option may be used to skip the
user info (part before the '@'). Most of time, the user info will be ignored.
The first flag, HTX_SL_F_HAS_AUTHORITY, is set when the uri contains an
authority. For the H1, it happens when a CONNECT request is received or when an
absolute uri is used. For the H2, it happens when the pseudo header ":authority"
is provided.
The second one, HTX_SL_F_NORMALIZED_URI, is set when the received uri is
represented as an absolute uri because of the protocol requirements. For now, it
is only used for h2 requests, when the pseudo headers :authority and :scheme are
found. Internally, the uri is represented as an absolute uri. This flag allows
us to make the difference between an absolute uri in h1 and h2.
This function now dumps info about the HTX message into a buffer, passed as
argument. In addition, it is possible to only dump meta information, without the
message content.
This function now uses the address of the pointer to the htx message where the
copy must be performed. This way, when a zero-copy is performed, there is no
need to refresh the caller's htx message. It is a bit easier to do that way,
especially to add traces in the mux-h1.
William reported that since commit 6b3089856f ("MEDIUM: fd: do not use
the FD_POLL_* flags in the pollers anymore") the master's CLI often
fails to access sub-processes. There are two causes to this. One is
that we did report FD_POLL_ERR on an FD as soon as FD_EV_SHUT_W was
seen, which is automatically inherited from POLLHUP. And since we do
not store the current shutdown state of an FD we can't know if the
poller reports a sudden close resulting from an error or just a
byproduct of a previous shutdown(WR) followed by a read0. The current
patch addresses this by only considering this when the FD was active,
since a shutdown FD is not active. The second issue is that *somewhere*
down the chain, channel data are ignored if an error is reported on a
channel. This results in content truncation, but this cause was not
figured yet.
No backport is needed.
It is now possible to format stats counters as floats. But the stats applet does
not use it.
This patch is required by the Prometheus exporter to send the time averages in
seconds. If the promex change is backported, this patch must be backported
first.
A different engine-id is now generated for each thread. So, it is possible to
enable the async mode with several threads.
This patch may be backported to older versions.
We often need ISO time + microseconds in traces and ring buffers, thus
function does this by calling gettimeofday() and keeping a cached value
of the part representing the tv_sec value, and only rewrites the microsecond
part. The cache is per-thread so it's lockless and safe to use as-is.
Some tests already show that it's easy to see 3-4 events in a single
microsecond, thus it's likely that the nanosecond version will have to
be implemented as well. But certain comments on the net suggest that
some parsers are having trouble beyond microsecond, thus for now let's
stick to the microsecond only.
Now that we can wake tasklet for other threads, make sure that if the thread
is sleeping, we wake it up, or the tasklet won't be executed until it's
done sleeping.
That also means that, before going to sleep, and after we put our bit
in sleeping_thread_mask, we have to check that nobody added a tasklet for
us, just checking for global_tasks_mask isn't enough anymore.
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%.
There are a number of tests there which are enforced on tasklets while
they will never apply (various handlers, destroyed task or not, arguments,
results, ...). Instead let's have a single TASK_IS_TASKLET() test and call
the tasklet processing function directly, skipping all the rest.
It now appears visible that the only unneeded code is the update to
curr_task that is never used for tasklets, except for opportunistic
reporting in the debug handler, which can only catch si_cs_io_cb,
which in practice doesn't appear in any report so the extra cost
incurred there is pointless.
This change alone removes 700 bytes of code, mostly in
process_runnable_tasks() and increases the performance by about
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().
Make it so MT_LIST_ADD and MT_LIST_ADDQ return 1 if it managed to add the
item, 0 (because it was already in a list) otherwise.
Make it so MT_LIST_DEL returns 1 if it managed to remove the item from a
list, or 0 otherwise (because it was in no list).
In srv_add_to_idle_list(), use LIST_DEL_INIT instead of just LIST_DEL.
We're about to add the connection to a mt_list, and MT_LIST_ADD/MT_LIST_ADDQ
will be modified to make sure we're not adding the element if it's already
in a list.
Add a few new macroes to the mt_lists.
MT_LIST_LOCK_ELT()/MT_LIST_UNLOCK_ELT() helps locking/unlocking an element.
This should only be used if you know for sure nobody else will remove the
element from the list in the meanwhile.
mt_list_for_each_entry_safe() is an iterator, similar to
list_for_each_entry_safe().
It takes 5 arguments, item, list_head, member are similar to those of
the non-mt variant, tmpelt is a temporary pointer to a struct mt_list, while
tmpelt2 is a struct mt_list itself.
MT_LIST_DEL_SELF() can be used to delete an item while parsing the list with
mt_list_for_each_entry_safe(). It shouldn't be used outside, and you
shouldn't use MT_LIST_DEL() while using mt_list_for_each_entry_safe().
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.
To avoid code duplication in the futur mux FCGI, functions parsing H1 messages
and converting them into HTX have been moved in the file h1_htx.c. Some
specific parts remain in the mux H1. But most of the parsing is now generic.
Application is a generic term here. It is a modules which handle its own log
server list, with no dependency on a proxy. Such applications can now call the
function app_log() to log messages, passing a log server list and a tag as
parameters. Internally, the function __send_log() has been adapted accordingly.
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.
This new flag may be used to report unexpected error because of not well
formatted HTX messages (not related to a parsing error) or our incapactity to
handle the processing because we reach a limit (ressource exhaustion, too big
headers...). It should result to an error 500 returned to the client when
applicable.
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.
When using "http-reuse safe", which is the default, a new incoming connection
does not automatically reuse an existing connection for the first request, as
we don't want to risk to lose the contents if we know the client will not be
able to replay the request. A side effect to this is that when dealing with
mostly http-close traffic, the reuse rate is extremely low and we keep
accumulating server-side connections that may even never be reused. At some
point we're limited to a ratio of file descriptors, but when the system is
configured with very high FD limits, we can still reach the limit of outgoing
source ports and make the system significantly slow down trying to find an
available port for outgoing connections. A simple test on my laptop with
ulimit 100000 and with the following config results in the load immediately
dropping after a few seconds :
listen l1
bind :4445
mode http
server s1 127.0.0.1:8000
As can be seen, the load falls from 38k cps to 400 cps during the first 200ms
(in fact when the source port table is full and connect() takes ages to find
a spare port for a new connection):
$ injectl464 -p 4 -o 1 -u 10 -G 127.0.0.1:4445/ -F -c -w 100
hits ^hits hits/s ^h/s bytes kB/s last errs tout htime sdht ptime
2439 2439 39338 39338 356094 5743 5743 0 0 0.4 0.5 0.4
7637 5198 38185 37666 1115002 5575 5499 0 0 0.7 0.5 0.7
7719 82 25730 820 1127002 3756 120 0 0 21.8 18.8 21.8
7797 78 19492 780 1138446 2846 114 0 0 61.4 2.5 61.4
7877 80 15754 800 1150182 2300 117 0 0 58.6 0.5 58.6
7920 43 13200 430 1156488 1927 63 0 0 58.9 0.3 58.9
At this point, lots of connections are indeed in use, for only 10 connections
on the frontend side:
$ ss -ant state established | wc -l
39022
This patch makes sure we never keep more idle connections than we've ever
had outstanding requests on a server. This way the total number of idle
connections will never exceed the sum of maximum connections. Thus highly
loaded servers will be able to get many connections and slightly loaded
servers will keep less. Ideally we should apply similar limits per process
and the per backend, but in practice this already addresses the issues
pretty well:
$ injectl464 -p 4 -o 1 -u 10 -G 127.0.0.1:4445/ -F -c -w 100
hits ^hits hits/s ^h/s bytes kB/s last errs tout htime sdht ptime
4423 4423 40209 40209 645758 5870 5870 0 0 0.2 0.4 0.2
8020 3597 40100 39966 1170920 5854 5835 0 0 0.2 0.4 0.2
12037 4017 40123 40170 1757402 5858 5864 0 0 0.2 0.4 0.2
16069 4032 40172 40320 2346074 5865 5886 0 0 0.2 0.4 0.2
20047 3978 40013 39386 2926862 5842 5750 0 0 0.3 0.4 0.3
24005 3958 40008 39979 3504730 5841 5837 0 0 0.2 0.4 0.2
$ ss -ant state established | wc -l
234
This patch must be backported to 2.0. It could be useful in 1.9 as well
eventhough pools and reuse are not enabled by default there.
As mentioned in previous commit, these flags do not map well to
modern poller capabilities. Let's use the FD_EV_*_{R,W} flags instead.
This first patch only performs a 1-to-1 mapping making sure that the
previously reported flags are still reported identically while using
the closest possible semantics in the pollers.
It's worth noting that kqueue will now support improvements such as
returning distinctions between shut and errors on each direction,
though this is not exploited for now.
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.
These two functions are used to enable recv/send but only if the FD is
not marked as active yet. The purpose is to conditionally mark them as
tentatively usable without interfering with the polling if polling was
already enabled, when it's supposed to be likely true.
Given that all our I/Os are now directed from top to bottom and not the
opposite way around, and the FD cache was removed, it doesn't make sense
anymore to create FDs that are marked not ready since this would prevent
the first accesses unless the caller explicitly does an fd_may_recv()
which is not expected to be its job (which conn_ctrl_init() has to do
by the way). Let's move this into fd_insert() instead, and have a single
atomic operation for both directions via fd_may_both().
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.
In prompts on the CLI we now commonly need to propose a keyword name
and a description and it doesn't make sense to define a new struct for
each such pairs. Let's simply have a generic "name_desc" for this.
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.
Previously the callback was almost mandatory so it made sense to have it
before the message. Now that it can default to the one declared in the
trace source, most TRACE() calls contain series of empty args and callbacks,
which make them suitable for being at the end and being totally omitted.
This patch thus reverses the TRACE arguments so that the message appears
first, then the mask, then arg1..arg4, then the callback. In practice
we'll mostly see 1 arg, or 2 args and nothing else, and it will not be
needed anymore to pass long series of commas in the middle of the
arguments. However if a source is enforced, the empty commas will still
be needed for all omitted arguments.
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.
The three functions (attach, IO handler, and release) are meant to be
called by any CLI command which requires to dump the contents of a ring
buffer. We do not implement anything generic to dump any ring buffer on
the CLI since it's meant to be used by other functionalities above.
However these functions deal with locking and everything so it's trivial
to embed them in other code.
This function tries to write to the ring buffer, possibly removing enough
old messages to make room for the new one. It takes two arrays of fragments
on input to ease the insertion of prefixes by the caller. It atomically
writes the message, possibly truncating it if desired, and returns the
operation's status.
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.
The new functions are :
__b_put_varint() : inserts a varint when it's known that it fits
b_put_varint() : tries to insert a varint at the tail
b_get_varint() : tries to get a varint from the head
b_peek_varint() : tries to peek a varint at a specific offset
Wrapping is supported so that they are expected to be safe to use to
manipulate varints with buffers anywhere.
It will sometimes be useful to encode varints to know the output size in
advance. Two versions are provided, one inline using a switch/case construct
which will be trivial for use with constants (and will be very fast albeit
huge) and one function iterating on the number which is 5 times smaller,
for use with variables.
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 new TRACE_<level>() macros take a mask, 4 args, a callback and a
static message. From this they also inherit the TRACE_SOURCE macro from
the caller, which contains the pointer to the trace source (so that it's
not required to paste it everywhere), and an ist string is also made by
the concatenation of the file name and the line number. This uses string
concatenation by the preprocessor, and turns it into an ist by the compiler
so that there is no operation at all to perform to adjust the data length
as the compiler knows where to cut during the optimization phase. Last,
the message is also automatically turned into an ist so that it's trivial
to put it into an iovec without having to run strlen() on it.
All arguments and the callback may be empty and will then automatically
be replaced with a NULL pointer. This makes the TRACE calls slightly
lighter especially since arguments are not always used. Several other
options were considered to use variadic macros but there's no outstanding
rule that justifies to place an argument before another one, and it still
looks convenient to have the message be the last one to encourage copy-
pasting of the trace statements.
A generic TRACE() macro takes TRACE_LEVEL in from the source file as the
trace level instead of taking it from its name. This may slightly simplify
the production of traces that always run at the same level (internal core
parts may probably only be called at developer level).
The trace() call will support an optional decoding callback and 4
arguments that this function is supposed to know how to use to provide
extra information. The output remains unchanged when the function is
NULL. Otherwise, the message is pre-filled into the thread-local
trace_buf, and the function is called with all arguments so that it
completes the buffer in a readable form depending on the expected
level of detail.
This new "level" argument will allow the trace sources to label the
traces for different purposes, and filter out some of them if they
are not relevant to the current target. Right now we have 5 different
levels:
- USER : the least verbose one, only a few functional information
- PAYLOAD: like user but also displays some payload-related information
- PROTO: focuses on the protocol's framing
- STATE: also indicate state internal transitions or non-transitions
- DEVELOPER: adds extra info about branches taken in the code (break
points, return points)
We now pass an extra argument "where" to the trace() call, which
is supposed to be an ist made of the concatenation of the filename
and the line number. We only keep the last 10 chars from this string
since the end of file names is most often easy to recognize. This
gives developers useful information at very low cost.
For now it remains quite basic. It performs a few state checks, calls
the source's sink if defined, and performs the transitions between
RUNNING, STOPPED and WAITING when the configured events match.
For now it lists the sources if one is not provided, and checks
for the source's existence. It lists the events if not provided,
checks for their existence if provided, and adjusts reported
events/start/stop/pause events, and performs state transitions.
It lists sinks and adjusts them as well. Filters, lock, and
level are not implemented yet.
