                                  ------
                                  HATerm
                                  ------
                           HAProxy's dummy HTTP
                           server for benchmarks

1. Background
-------------

HATerm is a dummy HTTP server that leverages the flexible and scalable
architecture of HAProxy to ease benchmarking of HTTP agents in all versions of
HTTP currently supported by HAProxy (HTTP/1, HTTP/2, HTTP/3), and both in clear
and TLS / QUIC. It follows the same principle as its ancestor HTTPTerm [1],
consisting in producing HTTP responses entirely configured by the request
parameters (size, response time, status etc). It also preserves the spirit
HTTPTerm which does not require any configuration beyond an optional listening
address and a port number, though it also supports advanced configurations with
the full spectrum of HAProxy features for specific testing. The goal remains
to make it almost as fast as the original HTTPTerm so that it can become a
de-facto replacement, with a compatible command line and request parameters
that will not change users' habits.

  [1] https://github.com/wtarreau/httpterm


2. Compilation
--------------

HATerm may be compiled in the same way as HAProxy but with "haterm" as Makefile
target to provide on the "make" command line as follows:

  $ make -j $(nproc) TARGET=linux-glibc haterm

HATerm supports HTTPS/SSL/TCP:

  $ make TARGET=linux-glibc USE_OPENSSL=1 haterm

It also supports QUIC:

  $ make -j $(nproc) TARGET=linux-glibc USE_OPENSSL=1 USE_QUIC=1 haterm

Technically speaking, it uses the regular HAProxy source and object code with a
different command line parser. As such, all build options supported by HAProxy
also apply to HATerm. See INSTALL for more details about how to compile them.


3. Execution
------------

HATerm is a very easy to use HTTP server with supports for all the HTTP
versions. It displays its usage when run without argument or wrong arguments:

    $ ./haterm
    Usage : haterm -L [<ip>]:<clear port>[:<TCP&QUIC SSL port>] [-L...]* [opts]
    where <opts> may be any combination of:
        -G <line> : multiple option; append <line> to the "global" section
        -F <line> : multiple option; append <line> to the "frontend" section
        -T <line> : multiple option; append <line> to the "traces" section
        -C : dump the configuration and exit
        -D : goes daemon
        -b <keysize> : RSA key size in bits (ex: "2048", "4096"...)
        -c <curves> : ECDSA curves (ex: "P-256", "P-384"...)
        -v : shows version
        -d : enable the traces for all http protocols
        --quic-bind-opts <opts> : append options to QUIC "bind" lines
        --tcp-bind-opts <opts> : append options to TCP "bind" lines


Arguments -G, -F, -T permit to append one or multiple lines at the end of their
respective sections. A tab character ('\t') is prepended at the beginning of
the argument, and a line feed ('\n') is appended at the end. It is also
possible to insert multiple lines at once using escape sequences '\n' and '\t'
inside the string argument.

As HAProxy, HATerm may listen on several TCP/UDP addresses which can be
provided by multiple "-L" options. To be functional, it needs at least one
correct "-L" option to be set.

Examples:

    $ ./haterm -L 127.0.0.1:8888        # listen on 127.0.0.1:8888 TCP address

    $ ./haterm -L 127.0.0.1:8888:8889   # listen on 127.0.0.1:8888 TCP address,
                                        # 127.0.01:8889 SSL/TCP address,
                                        # and 127.0.01:8889 QUIC/UDP address

    $ ./haterm -L 127.0.0.1:8888:8889 -L [::1]:8888:8889

With USE_QUIC_OPENSSL_COMPAT support, the user must configure a global
section as for HAProxy. HATerm sets internally its configuration in.
memory as this is done by HAProxy from configuration files:

    $ ./haterm -L 127.0.0.1:8888:8889
    [NOTICE]   (1371578) : haproxy version is 3.4-dev4-ba5eab-28
    [NOTICE]   (1371578) : path to executable is ./haterm
    [ALERT]    (1371578) : Binding [haterm cfgfile:12] for frontend
                           ___haterm_frontend___: this SSL library does not
                           support the QUIC protocol. A limited compatibility
                           layer may be enabled using the "limited-quic" global
                           option if desired.

Such an alert may be fixed with "-G' option:

    $ ./haterm -L 127.0.0.1:8888:8889 -G "limited-quic"


When the SSL support is not compiled in, the second port is ignored. This is
also the case for the QUIC support.

HATerm adjusts its responses depending on the requests it receives. An empty
query string provides the information about how the URIs are understood by
HATerm:

    $ curl http://127.0.0.1:8888/?
    HAProxy's dummy HTTP server for benchmarks - version 3.4-dev4.
    All integer argument values are in the form [digits]*[kmgr] (r=random(0..1))
    The following arguments are supported to override the default objects :
     - /?s=<size>        return <size> bytes.
                         E.g. /?s=20k
     - /?r=<retcode>     present <retcode> as the HTTP return code.
                         E.g. /?r=404
     - /?c=<cache>       set the return as not cacheable if <1.
                         E.g. /?c=0
     - /?A=<req-after>   drain the request body after sending the response.
                         E.g. /?A=1
     - /?C=<close>       force the response to use close if >0.
                         E.g. /?C=1
     - /?K=<keep-alive>  force the response to use keep-alive if >0.
                         E.g. /?K=1
     - /?t=<time>        wait <time> milliseconds before responding.
                         E.g. /?t=500
     - /?k=<enable>      Enable transfer encoding chunked with only one chunk
                         if >0.
     - /?R=<enable>      Enable sending random data if >0.

    Note that those arguments may be cumulated on one line separated by a set of
    delimiters among [&?,;/] :
     -  GET /?s=20k&c=1&t=700&K=30r HTTP/1.0
     -  GET /?r=500?s=0?c=0?t=1000 HTTP/1.0

