456 lines
22 KiB
Plaintext
456 lines
22 KiB
Plaintext
----------------------
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HAProxy how-to
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----------------------
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version 1.5-dev11
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willy tarreau
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2012/06/04
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1) How to build it
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------------------
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To build haproxy, you will need :
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- GNU make. Neither Solaris nor OpenBSD's make work with the GNU Makefile.
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However, specific Makefiles for BSD and OSX are provided.
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- GCC between 2.91 and 4.5.0. Others may work, but not tested.
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- GNU ld
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Also, you might want to build with libpcre support, which will provide a very
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efficient regex implementation and will also fix some badness on Solaris' one.
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To build haproxy, you have to choose your target OS amongst the following ones
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and assign it to the TARGET variable :
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- linux22 for Linux 2.2
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- linux24 for Linux 2.4 and above (default)
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- linux24e for Linux 2.4 with support for a working epoll (> 0.21)
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- linux26 for Linux 2.6 and above
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- linux2628 for Linux 2.6.28 and above (enables splice and tproxy)
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- solaris for Solaris 8 or 10 (others untested)
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- freebsd for FreeBSD 5 to 8.0 (others untested)
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- openbsd for OpenBSD 3.1 to 4.6 (others untested)
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- aix52 for AIX 5.2
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- cygwin for Cygwin
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- generic for any other OS.
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- custom to manually adjust every setting
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You may also choose your CPU to benefit from some optimizations. This is
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particularly important on UltraSparc machines. For this, you can assign
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one of the following choices to the CPU variable :
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- i686 for intel PentiumPro, Pentium 2 and above, AMD Athlon
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- i586 for intel Pentium, AMD K6, VIA C3.
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- ultrasparc : Sun UltraSparc I/II/III/IV processor
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- native : use the build machine's specific processor optimizations
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- generic : any other processor or no specific optimization. (default)
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Alternatively, you may just set the CPU_CFLAGS value to the optimal GCC options
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for your platform.
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You may want to build specific target binaries which do not match your native
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compiler's target. This is particularly true on 64-bit systems when you want
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to build a 32-bit binary. Use the ARCH variable for this purpose. Right now
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it only knows about a few x86 variants (i386,i486,i586,i686,x86_64), two
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generic ones (32,64) and sets -m32/-m64 as well as -march=<arch> accordingly.
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If your system supports PCRE (Perl Compatible Regular Expressions), then you
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really should build with libpcre which is between 2 and 10 times faster than
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other libc implementations. Regex are used for header processing (deletion,
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rewriting, allow, deny). The only inconvenient of libpcre is that it is not
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yet widely spread, so if you build for other systems, you might get into
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trouble if they don't have the dynamic library. In this situation, you should
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statically link libpcre into haproxy so that it will not be necessary to
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install it on target systems. Available build options for PCRE are :
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- USE_PCRE=1 to use libpcre, in whatever form is available on your system
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(shared or static)
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- USE_STATIC_PCRE=1 to use a static version of libpcre even if the dynamic
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one is available. This will enhance portability.
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- with no option, use your OS libc's standard regex implemntation (default).
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Warning! group references on Solaris seem broken. Use static-pcre whenever
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possible.
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Recent systems can resolve IPv6 host names using getaddrinfo(). This primitive
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is not present in all libcs and does not work in all of them either. Support in
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glibc was broken before 2.3. Some embedded libs may not properly work either,
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thus, support is disabled by default, meaning that some host names which only
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resolve as IPv6 addresses will not resolve and configs might emit an error
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during parsing. If you know that your OS libc has reliable support for
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getaddrinfo(), you can add USE_GETADDRINFO=1 on the make command line to enable
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it. This is the recommended option for most Linux distro packagers since it's
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working fine on all recent mainstream distros. It is automatically enabled on
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Solaris 8 and above, as it's known to work.
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It is possible to add native support for SSL using the GNU makefile only, and
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by passing "USE_OPENSSL=1" on the make commande line. The libssl and libcrypto
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will automatically be linked with haproxy. Some systems also require libz, so
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if the build fails due to missing symbols such as deflateInit(), then try again
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with "ADDLIB=-lz".
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It is also possible to include native support for ZLIB to benefit from HTTP
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compression. For this, pass "USE_ZLIB=1" on the "make" command line and ensure
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that zlib is present on the system.
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By default, the DEBUG variable is set to '-g' to enable debug symbols. It is
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not wise to disable it on uncommon systems, because it's often the only way to
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get a complete core when you need one. Otherwise, you can set DEBUG to '-s' to
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strip the binary.
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For example, I use this to build for Solaris 8 :
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$ make TARGET=solaris CPU=ultrasparc USE_STATIC_PCRE=1
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And I build it this way on OpenBSD or FreeBSD :
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$ make -f Makefile.bsd REGEX=pcre DEBUG= COPTS.generic="-Os -fomit-frame-pointer -mgnu"
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And on a recent Linux with SSL and ZLIB support :
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$ make TARGET=linux2628 CPU=native USE_PCRE=1 USE_OPENSSL=1 USE_ZLIB=1
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In order to build a 32-bit binary on an x86_64 Linux system with SSL support
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without support for compression but when OpenSSL requires ZLIB anyway :
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$ make TARGET=linux26 ARCH=i386 USE_OPENSSL=1 ADDLIB=-lz
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If you need to pass other defines, includes, libraries, etc... then please
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check the Makefile to see which ones will be available in your case, and
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use the USE_* variables in the GNU Makefile, or ADDINC, ADDLIB, and DEFINE
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variables in the BSD makefiles.
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AIX 5.3 is known to work with the generic target. However, for the binary to
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also run on 5.2 or earlier, you need to build with DEFINE="-D_MSGQSUPPORT",
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otherwise __fd_select() will be used while not being present in the libc.
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If you get build errors because of strange symbols or section mismatches,
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simply remove -g from DEBUG_CFLAGS.
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2) How to install it
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--------------------
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To install haproxy, you can either copy the single resulting binary to the
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place you want, or run :
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$ sudo make install
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If you're packaging it for another system, you can specify its root directory
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in the usual DESTDIR variable.
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3) How to set it up
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-------------------
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There is some documentation in the doc/ directory :
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- architecture.txt : this is the architecture manual. It is quite old and
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does not tell about the nice new features, but it's still a good starting
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point when you know what you want but don't know how to do it.
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- configuration.txt : this is the configuration manual. It recalls a few
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essential HTTP basic concepts, and details all the configuration file
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syntax (keywords, units). It also describes the log and stats format. It
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is normally always up to date. If you see that something is missing from
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it, please report it as this is a bug.
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- haproxy-en.txt / haproxy-fr.txt : these are the old outdated docs. You
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should never need them. If you do, then please report what you didn't
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find in the other ones.
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- gpl.txt / lgpl.txt : the copy of the licenses covering the software. See
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the 'LICENSE' file at the top for more information.
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- the rest is mainly for developers.
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There are also a number of nice configuration examples in the "examples"
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directory as well as on several sites and articles on the net which are linked
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to from the haproxy web site.
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4) How to report a bug
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----------------------
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It is possible that from time to time you'll find a bug. A bug is a case where
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what you see is not what is documented. Otherwise it can be a misdesign. If you
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find that something is stupidly design, please discuss it on the list (see the
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"how to contribute" section below). If you feel like you're proceeding right
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and haproxy doesn't obey, then first ask yourself if it is possible that nobody
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before you has even encountered this issue. If it's unlikely, the you probably
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have an issue in your setup. Just in case of doubt, please consult the mailing
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list archives :
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http://www.formilux.org/archives/haproxy/
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http://marc.info/?l=haproxy
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Otherwise, please try to gather the maximum amount of information to help
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reproduce the issue and send that to the mailing list :
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haproxy@formilux.org
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Please include your configuration and logs. You can mask your IP addresses and
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passwords, we don't need them. But it's essential that you post your config if
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you want people to guess what is happening.
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Also, keep in mind that haproxy is designed to NEVER CRASH. If you see it die
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without any reason, then it definitely is a critical bug that must be reported
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and urgently fixed. It has happened a couple of times in the past, essentially
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on development versions running on new architectures. If you think your setup
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is fairly common, then it is possible that the issue is totally unrelated.
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Anyway, if that happens, feel free to contact me directly, as I will give you
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instructions on how to collect a usable core file, and will probably ask for
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other captures that you'll not want to share with the list.
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5) How to contribute
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--------------------
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It is possible that you'll want to add a specific feature to satisfy your needs
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or one of your customers'. Contributions are welcome, however I'm often very
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picky about changes. I will generally reject patches that change massive parts
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of the code, or that touch the core parts without any good reason if those
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changes have not been discussed first.
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The proper place to discuss your changes is the HAProxy Mailing List. There are
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enough skilled readers to catch hazardous mistakes and to suggest improvements.
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I trust a number of them enough to merge a patch if they say it's OK, so using
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the list is the fastest way to get your code reviewed and merged. You can
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subscribe to it by sending an empty e-mail at the following address :
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haproxy+subscribe@formilux.org
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If you have an idea about something to implement, *please* discuss it on the
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list first. It has already happened several times that two persons did the same
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thing simultaneously. This is a waste of time for both of them. It's also very
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common to see some changes rejected because they're done in a way that will
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conflict with future evolutions, or that does not leave a good feeling. It's
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always unpleasant for the person who did the work, and it is unpleasant for me
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too because I value people's time and efforts. That would not happen if these
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were discussed first. There is no problem posting work in progress to the list,
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it happens quite often in fact. Also, don't waste your time with the doc when
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submitting patches for review, only add the doc with the patch you consider
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ready to merge.
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If your work is very confidential and you can't publicly discuss it, you can
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also mail me directly about it, but your mail may be waiting several days in
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the queue before you get a response.
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If you'd like a feature to be added but you think you don't have the skills to
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implement it yourself, you should follow these steps :
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1. discuss the feature on the mailing list. It is possible that someone
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else has already implemented it, or that someone will tell you how to
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proceed without it, or even why not to do it. It is also possible that
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in fact it's quite easy to implement and people will guide you through
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the process. That way you'll finally have YOUR patch merged, providing
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the feature YOU need.
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2. if you really can't code it yourself after discussing it, then you may
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consider contacting someone to do the job for you. Some people on the
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list might be OK with trying to do it. Otherwise, you can check the list
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of contributors at the URL below, some of the regular contributors may
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be able to do the work, probably not for free but their time is as much
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valuable as yours after all, you can't eat the cake and have it too.
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The list of past and regular contributors is available below. It lists not only
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significant code contributions (features, fixes), but also time or money
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donations :
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http://haproxy.1wt.eu/contrib.html
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Note to contributors: it's very handy when patches comes with a properly
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formated subject. There are 3 criteria of particular importance in any patch :
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- its nature (is it a fix for a bug, a new feature, an optimization, ...)
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- its importance, which generally reflects the risk of merging/not merging it
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- what area it applies to (eg: http, stats, startup, config, doc, ...)
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It's important to make these 3 criteria easy to spot in the patch's subject,
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because it's the first (and sometimes the only) thing which is read when
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reviewing patches to find which ones need to be backported to older versions.
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Specifically, bugs must be clearly easy to spot so that they're never missed.
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Any patch fixing a bug must have the "BUG" tag in its subject. Most common
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patch types include :
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- BUG fix for a bug. The severity of the bug should also be indicated
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when known. Similarly, if a backport is needed to older versions,
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it should be indicated on the last line of the commit message. If
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the bug has been identified as a regression brought by a specific
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patch or version, this indication will be appreciated too. New
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maintenance releases are generally emitted when a few of these
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patches are merged.
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- CLEANUP code cleanup, silence of warnings, etc... theorically no impact.
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These patches will rarely be seen in stable branches, though they
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may appear when they remove some annoyance or when they make
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backporting easier. By nature, a cleanup is always minor.
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- REORG code reorganization. Some blocks may be moved to other places,
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some important checks might be swapped, etc... These changes
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always present a risk of regression. For this reason, they should
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never be mixed with any bug fix nor functional change. Code is
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only moved as-is. Indicating the risk of breakage is highly
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recommended.
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- BUILD updates or fixes for build issues. Changes to makefiles also fall
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into this category. The risk of breakage should be indicated if
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known. It is also appreciated to indicate what platforms and/or
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configurations were tested after the change.
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- OPTIM some code was optimised. Sometimes if the regression risk is very
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low and the gains significant, such patches may be merged in the
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stable branch. Depending on the amount of code changed or replaced
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and the level of trust the author has in the change, the risk of
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regression should be indicated.
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- RELEASE release of a new version (development or stable).
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- LICENSE licensing updates (may impact distro packagers).
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When the patch cannot be categorized, it's best not to put any tag. This is
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commonly the case for new features, which development versions are mostly made
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of.
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Additionally, the importance of the patch should be indicated when known. A
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single upper-case word is preferred, among :
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- MINOR minor change, very low risk of impact. It is often the case for
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code additions that don't touch live code. For a bug, it generally
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indicates an annoyance, nothing more.
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- MEDIUM medium risk, may cause unexpected regressions of low importance or
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which may quickly be discovered. For a bug, it generally indicates
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something odd which requires changing the configuration in an
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undesired way to work around the issue.
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- MAJOR major risk of hidden regression. This happens when I rearrange
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large parts of code, when I play with timeouts, with variable
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initializations, etc... We should only exceptionally find such
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patches in stable branches. For a bug, it indicates severe
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reliability issues for which workarounds are identified with or
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without performance impacts.
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- CRITICAL medium-term reliability or security is at risk and workarounds,
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if they exist, might not always be acceptable. An upgrade is
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absolutely required. A maintenance release may be emitted even if
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only one of these bugs are fixed. Note that this tag is only used
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with bugs. Such patches must indicate what is the first version
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affected, and if known, the commit ID which introduced the issue.
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If this criterion doesn't apply, it's best not to put it. For instance, most
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doc updates and most examples or test files are just added or updated without
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any need to qualify a level of importance.
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The area the patch applies to is quite important, because some areas are known
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to be similar in older versions, suggesting a backport might be desirable, and
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conversely, some areas are known to be specific to one version. When the tag is
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used alone, uppercase is preferred for readability, otherwise lowercase is fine
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too. The following tags are suggested but not limitative :
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- doc documentation updates or fixes. No code is affected, no need to
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upgrade. These patches can also be sent right after a new feature,
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to document it.
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- examples example files. Be careful, sometimes these files are packaged.
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- tests regression test files. No code is affected, no need to upgrade.
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- init initialization code, arguments parsing, etc...
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- config configuration parser, mostly used when adding new config keywords
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- http the HTTP engine
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- stats the stats reporting engine as well as the stats socket CLI
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- checks the health checks engine (eg: when adding new checks)
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- acl the ACL processing core or some ACLs from other areas
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- peers the peer synchronization engine
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- listeners everything related to incoming connection settings
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- frontend everything related to incoming connection processing
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- backend everything related to LB algorithms and server farm
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- session session processing and flags (very sensible, be careful)
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- server server connection management, queueing
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- proxy proxy maintenance (start/stop)
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- log log management
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- poll any of the pollers
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- halog the halog sub-component in the contrib directory
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- contrib any addition to the contrib directory
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Other names may be invented when more precise indications are meaningful, for
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instance : "cookie" which indicates cookie processing in the HTTP core. Last,
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indicating the name of the affected file is also a good way to quickly spot
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changes. Many commits were already tagged with "stream_sock" or "cfgparse" for
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instance.
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It is desired that AT LEAST one of the 3 criteria tags is reported in the patch
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subject. Ideally, we would have the 3 most often. The two first criteria should
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be present before a first colon (':'). If both are present, then they should be
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delimited with a slash ('/'). The 3rd criterion (area) should appear next, also
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followed by a colon. Thus, all of the following messages are valid :
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Examples of messages :
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- DOC: document options forwardfor to logasap
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- DOC/MAJOR: reorganize the whole document and change indenting
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- BUG: stats: connection reset counters must be plain ascii, not HTML
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- BUG/MINOR: stats: connection reset counters must be plain ascii, not HTML
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- MEDIUM: checks: support multi-packet health check responses
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- RELEASE: Released version 1.4.2
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- BUILD: stats: stdint is not present on solaris
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- OPTIM/MINOR: halog: make fgets parse more bytes by blocks
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- REORG/MEDIUM: move syscall redefinition to specific places
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Please do not use square brackets anymore around the tags, because they give me
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more work when merging patches. By default I'm asking Git to keep them but this
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causes trouble when patches are prefixed with the [PATCH] tag because in order
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not to store it, I have to hand-edit the patches. So as of now, I will ask Git
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to remove whatever is located between square brackets, which implies that any
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subject formatted the old way will have its tag stripped out.
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In fact, one of the only square bracket tags that still makes sense is '[RFC]'
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at the beginning of the subject, when you're asking for someone to review your
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change before getting it merged. If the patch is OK to be merged, then I can
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merge it as-is and the '[RFC]' tag will automatically be removed. If you don't
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want it to be merged at all, you can simply state it in the message, or use an
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alternate '[WIP]' tag ("work in progress").
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The tags are not rigid, follow your intuition first, anyway I reserve the right
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to change them when merging the patch. It may happen that a same patch has a
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different tag in two distinct branches. The reason is that a bug in one branch
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may just be a cleanup in the other one because the code cannot be triggered.
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For a more efficient interaction between the mainline code and your code, I can
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only strongly encourage you to try the Git version control system :
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http://git-scm.com/
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It's very fast, lightweight and lets you undo/redo your work as often as you
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want, without making your mistakes visible to the rest of the world. It will
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definitely help you contribute quality code and take other people's feedback
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in consideration. In order to clone the HAProxy Git repository :
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$ git clone http://git.1wt.eu/git/haproxy-1.4.git (stable 1.4)
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$ git clone http://git.1wt.eu/git/haproxy.git/ (development)
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If you decide to use Git for your developments, then your commit messages will
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have the subject line in the format described above, then the whole description
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of your work (mainly why you did it) will be in the body. You can directly send
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your commits to the mailing list, the format is convenient to read and process.
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-- end
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