"log-balance" directive was recently introduced to configure the
balancing algorithm to use when in a log backend. However, it is
confusing and it causes issues when used in default section.
In this patch, we take another approach: first we remove the
"log-balance" directive, and instead we rely on existing "balance"
directive to configure log load balancing in log backend.
Some algorithms such as roundrobin can be used as-is in a log backend,
and for log-only algorithms, they are implemented as "log-$name" inside
the "backend" directive.
The documentation was updated accordingly.
hash lb algorithm can be configured with the "log-balance hash <cnv_list>"
directive. With this algorithm, the user specifies a converter list with
<cnv_list>.
The produced log message will be passed as-is to the provided converter
list, and the resulting hash will be used to select the log server that
will receive the log message.
Using "mode log" in a backend section turns the proxy in a log backend
which can be used to log-balance logs between multiple log targets
(udp or tcp servers)
log backends can be used as regular log targets using the log directive
with "backend@be_name" prefix, like so:
| log backend@mybackend local0
A log backend will distribute log messages to servers according to the
log load-balancing algorithm that can be set using the "log-balance"
option from the log backend section. For now, only the roundrobin
algorithm is supported and set by default.
Refactor alloc_bind_address() function which is used to allocate a
sockaddr if a connection to a target server relies on a specific source
address setting.
The main objective of this change is to be able to use this function
outside of backend module, namely for preconnections using a reverse
server. As such, this function is now exported globally.
For reverse connect, there is no stream instance. As such, the function
parts which relied on it were reduced to the minimal. Now, stream is
only used if a non-static address is configured which is useful for
usesrc client|clientip|hdr_ip. These options have no sense for reverse
connect so it should be safe to use the same function.
This puts an end to the occasional confusion between the "now" date
that is internal, monotonic and not synchronized with the system's
date, and "date" which is the system's date and not necessarily
monotonic. Variable "now" was removed and replaced with a 64-bit
integer "now_ns" which is a counter of nanoseconds. It wraps every
585 years, so if all goes well (i.e. if humanity does not need
haproxy anymore in 500 years), it will just never wrap. This implies
that now_ns is never nul and that the zero value can reliably be used
as "not set yet" for a timestamp if needed. This will also simplify
date checks where it becomes possible again to do "date1<date2".
All occurrences of "tv_to_ns(&now)" were simply replaced by "now_ns".
Due to the intricacies between now, global_now and now_offset, all 3
had to be turned to nanoseconds at once. It's not a problem since all
of them were solely used in 3 functions in clock.c, but they make the
patch look bigger than it really is.
The clock_update_local_date() and clock_update_global_date() functions
are now much simpler as there's no need anymore to perform conversions
nor to round the timeval up or down.
The wrapping continues to happen by presetting the internal offset in
the short future so that the 32-bit now_ms continues to wrap 20 seconds
after boot.
The start_time used to calculate uptime can still be turned to
nanoseconds now. One interrogation concerns global_now_ms which is used
only for the freq counters. It's unclear whether there's more value in
using two variables that need to be synchronized sequentially like today
or to just use global_now_ns divided by 1 million. Both approaches will
work equally well on modern systems, the difference might come from
smaller ones. Better not change anyhting for now.
One benefit of the new approach is that we now have an internal date
with a resolution of the nanosecond and the precision of the microsecond,
which can be useful to extend some measurements given that timestamps
also have this resolution.
Instead we're using ns_to_sec(tv_to_ns(&now)) which allows the tv_sec
part to disappear. At this point, "now" is only used as a timeval in
clock.c where it is updated.
When a proxy enters the STOPPED state, it will no longer accept new
connections.
However, it doesn't mean that it's completely inactive yet: it will
still be able to handle already pending / keep-alive connections,
thus finishing ongoing work before effectively stopping.
be_usable_srv(), which is used by nbsrv converter and sample fetch,
will return 0 if the proxy is either stopped or disabled.
nbsrv behaves this way since it was originally implemented in b7e7c4720
("MINOR: Add nbsrv sample converter").
(Since then, multiple refactors were performed around this area, but
the current implementation still follows the same logic)
It was found that if nbsrv is used in a proxy section to perform routing
logic, unexpected decisions are being made when nbsrv is used on a proxy
with STOPPED state, since in-flight requests will suffer from nbsrv
returning 0 instead of the current number of usable servers which may
still process existing connections.
For instance, this can happen during process soft-stop, or even when
stopping the proxy from the cli / lua.
To fix this: we now make sure be_usable_srv() always returns the
current number of usable servers, unless the proxy is explicitly
disabled (from the config, not at runtime)
This could be backported up to 2.6.
For older versions, the need for a backport should be evaluated first.
--
Note for 2.4: proxy flags did not exist, it was implemented with fd10ab5e
("MINOR: proxy: Introduce proxy flags to replace disabled bitfield")
For 2.2: STOPPED and DISABLED states were not separated, so we have no
easy way to apply the fix anyway.
This change is required to support TCP/HTTP rules in defaults sections. The
'disabled' bitfield in the proxy structure, used to know if a proxy is
disabled or stopped, is replaced a generic bitfield named 'flags'.
PR_DISABLED and PR_STOPPED flags are renamed to PR_FL_DISABLED and
PR_FL_STOPPED respectively. In addition, everywhere there is a test to know
if a proxy is disabled or stopped, there is now a bitwise AND operation on
PR_FL_DISABLED and/or PR_FL_STOPPED flags.
There is currently a problem related to time keeping. We're mixing
the functions to perform calculations with the os-dependent code
needed to retrieve and adjust the local time.
This patch extracts from time.{c,h} the parts that are solely dedicated
to time keeping. These are the "now" or "before_poll" variables for
example, as well as the various now_*() functions that make use of
gettimeofday() and clock_gettime() to retrieve the current time.
The "tv_*" functions moved there were also more appropriately renamed
to "clock_*".
Other parts used to compute stolen time are in other files, they will
have to be picked next.
The remaining proxy states were only used to distinguish an enabled
proxy from a disabled one. Due to the initialization order, both
PR_STNEW and PR_STREADY were equivalent after startup, and they
would only differ from PR_STSTOPPED when the proxy is disabled or
shutdown (which is effectively another way to disable it).
Now we just have a "disabled" field which allows to distinguish them.
It's becoming obvious that start_proxies() is only used to print a
greeting message now, that we'd rather get rid of. Probably that
zombify_proxy() and stop_proxy() should be merged once their
differences move to the right place.
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.
This one was not easy because it was embarking many includes with it,
which other files would automatically find. At least global.h, arg.h
and tools.h were identified. 93 total locations were identified, 8
additional includes had to be added.
In the rare files where it was possible to finalize the sorting of
includes by adjusting only one or two extra lines, it was done. But
all files would need to be rechecked and cleaned up now.
It was the last set of files in types/ and proto/ and these directories
must not be reused anymore.
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.
The files remained mostly unchanged since they were OK. However, half of
the users didn't need to include them, and about as many actually needed
to have it and used to find functions like srv_currently_usable() through
a long chain that broke when moving the file.
