This new configuration manual intends to document every known keyword
of the configuration language. Right now, it enumerates them all and
describes how to use ACLs.
The GCD used when computing the servers' weights causes the total
weight of the backend to appear lower than expected because it is
divided by the GCD. Easy solution consists in recomputing the GCD
from the first server and apply it to the global weight.
When a very large number of servers is configured (thousands),
shutting down many of them at once could lead to large number
of calls to recalc_server_map() which already takes some time.
This would result in an O(N^3) computation time, leading to
noticeable pauses on slow embedded CPUs on test platforms.
Instead, mark the map as dirty and recalc it only when needed.
Now we try to free as many pools as possible when a proxy is stopping.
The reason is that we want to ease the process replacement when applying
a new configuration, without keeping too many unused memory allocated.
It's now as easy as passing "DLMALLOC_SRC=<path_to_dlmalloc.c>" to
build with support for dlmalloc. The dlmalloc source is not provided
with haproxy in order to ensure that people will use either the most
recent, or the most suited version for their platform. The minimal
mmap size is specified in DLMALLOC_THRES, which defaults to 4096. It
should be increased on platforms with larger pages (eg: 8 kB on some
64 bit systems).
- acl: smarter integer comparison support in ACLs
- acl: specify the direction during fetches
- acl: provide the argument length for fetch functions
- acl: provide a reference to the expr to fetch()
- acl: implement matching on header values
- acl: support maching on 'path' component
- acl: permit to return any header when no name specified
- errorfile: use a local file to feed error messages
- negation in ACL conds was not cleared between terms
- fix segfault at exit when using captures
- improve memory freeing upon exit
- acl: support '-i' to ignore case when matching
- str2net() must not change the const char *
- provide default ACLs
- acl: distinguish between request and response headers
- added the 'use_backend' keyword for full content-switching
- acl: added the TRUE and FALSE ACLs.
- shut warnings 'is*' macros from ctype.h on solaris
Those ACLs are sometimes useful for troubleshooting. Two ACL subjects
"always_true" and "always_false" have been added too. They return what
their subject says for every pattern. Also, acl_match_pst() has been
removed.
The new "use_backend" keyword permits full content switching by the
use of ACLs. Its usage is simple :
use_backend <backend_name> {if|unless} <acl_cond>
Implemented the "-i" option on ACLs to state that the matching
will have to be performed for all patterns ignoring case. The
usage is :
acl <aclname> <aclsubject> -i pattern1 ...
If a pattern must begin with "-", either it must not be the first one,
or the "--" option should be specified first.
The deinit() function is specialized in memory area freeing.
There were a ton of information that were not released at the
exit time, which made valgrind complain. Now, most of the entries
are freed. However, it seems like regfree() does not completely
free a regex (12 bytes lost per regex).
since pools v2, the way pools were destroyed at exit is incorrect
because it ought to account for users of those pools before freeing
them. This test also ensures there is no double free.
It is now possible to read error messages from local files,
using the 'errorfile' keyword. Those files are read during
parsing, so there's no I/O involved. They make it possible
to return custom error messages with custom status and headers.
'path', 'path_reg', 'path_beg', 'path_end', 'path_sub', 'path_dir'
and 'path_dom' have been implemented to process the path component
of the URI. It starts after the host part, and stops before the
question mark.
hdr(x), hdr_reg(x), hdr_beg(x), hdr_end(x), hdr_sub(x), hdr_dir(x),
hdr_dom(x), hdr_cnt(x) and hdr_val(x) have been implemented. They
apply to any of the possibly multiple values of header <x>.
Right now, hdr_val() is limited to integer matching, but it should
reasonably be upgraded to match long long ints.
Some fetches such as 'line' or 'hdr' need to know the direction of
the test (request or response). A new 'dir' parameter is now
propagated from the caller to achieve this.
ACLs now support operators such as 'eq', 'le', 'lt', 'ge' and 'gt'
in order to give more flexibility to the language. Because of this
change, the 'dst_limit' keyword changed to 'dst_conn' and now requires
either a range or a test such as 'dst_conn lt 1000' which is more
understandable.
- do not re-arm read timeout in SHUTR state
- optimize I/O by detecting system starvation
- the epoll FD must not be shared between processes
- limit the number of events returned by *poll*
By default, epoll/kqueue used to return as many events as possible.
This could sometimes cause huge latencies (latencies of up to 400 ms
have been observed with many thousands of fds at once). Limiting the
number of events returned also reduces the latency by avoiding too
many blind processing. The value is set to 200 by default and can be
changed in the global section using the tune.maxpollevents parameter.
Recreate the epoll file descriptor after a fork(). It will ensure
that all processes will not share their epoll_fd. Some side effects
were encountered because of this, such as epoll_wait() returning an
FD which was previously deleted, in multi-process mode.
Compare the results of recv/send with the parameter passed and
detect whether the system has no free buffer space for send()
or has no data anymore for recv(). This dramatically reduces
the number of syscalls (by about 23%).
A second occurrence of read-timeout rearming was present in stream_sock.c.
To fix the problem, it was necessary to put the shutdown information in
the buffer (already planned).
There is a long-time bug causing busy loops when either client-side
or server-side enters a SHUTR state. When writing data to the FD,
it was possible to re-arm the read side if the write had been paused.
ETERNITY is not 0 anymore, so all timeouts will not be initialized
to ETERNITY by a simple calloc(). We have to explictly assign them.
This bug caused random session aborts.
- fixed ev_sepoll again by rewriting the state machine
- switched all timeouts to timevals instead of milliseconds
- improved memory management using mempools v2.
- several minor optimizations
wake_expired_tasks() used a hint to avoid scanning the tree in most cases,
but it looks like the hint is more expensive than reaching the first node
in the tree. Disable it for now.
Introduction of timeval timers broke *poll-based pollers, because the call to
tv_ms_remain may return 0 while the event is not elapsed yet. Now we carefully
check for those cases and round the result up by 1 ms.
When we're interrupted by another instance, it is very likely
that the other one will need some memory. Now we know how to
free what is not used, so let's do it.
Also only free non-null pointers. Previously, pool_destroy()
did implicitly check for this case which was incidentely
needed.
- keep the number of users of each pool
- call the garbage collector on out of memory conditions
- sort the pools by size for faster creation
- force the alignment size to 16 bytes instead of 4*sizeof(void *)
Also during this process, a bug was found in appsession_refresh().
It would not automatically requeue the task in the queue, so the
old sessions would not vanish.
