lizard

Lizard is a multithreaded HTTP server engine.

Architecture

A lizard-based application is basically a plugin into the engine, which must provide callbacks for handling HTTP requests.

The callbacks are handled by two separately configurable pools of threads, "easy" threads and "hard" threads. The logic behind it is that "easy" thread can pass any request to the "hard" one, and the "hard" thread can either process the request or fail, in which case 503 will be returned to the client

The plugin may be built either as dynamically loaded .so or statically linked with the engine into a single binary.

Build requirements

• Linux system (tested mainly on x86_64, but will probably work on x86 as well).
• cmake.
• gcc.
• Boost thread library.
• Judy memory arrays library.
• Expat XML parser library.

Plugin interface

• handle_easy - common HTTP request handler.
• handle_hard - extra HTTP requtest handler
• set_param - configuration callback. Lizard calls it providing the configuration file name for plugin to parse it for options, if any.
• idle - arbitary periodically called function.

The plugin must be a class inherited from lizard::plugin class. For reference please consult src/test*/.

Configuration

Config file

The configuration file for both the engine and the plugin is in XML format.

For the engine, it provides the following options:

 * <pid_file_name>        - pid-file name (for usage in daemontools etc. it can also be provided via a command-line option)
 * <log_file_name>        - log file name.
 * <log_level>            - log level, which can be any of: alert crit error warn notice info debug (sorted by descent of importance)
 * <access_log_file_name> - if this option is not empty, access log file name.

 * <stats>                - stats handler listen options.

 * <plugin>               - plugin options:
     ** <ip>,<port>            - address and port to listen for incoming connections on.
     ** <connection_timeout>   - handler connection timeout.
     ** <idle_timeout>         - plugin idle function call period.

     ** <library>              - the path to plugin .so (irrelevant if linked statically, but still should be present).

     ** <easy_threads>         - "easy" thread count
     ** <hard_threads>         - "hard" thread count
     ** <easy_queue_limit>     - "easy" queue limit (no limit if not specified).
     ** <hard_queue_limit>     - "hard" queue limit (no limit if not specified).

Any plugin options should be contained in the same file as valid XML entries inside the root (`<lizard>`) tag.

Command-line options

• -c, --config-file <path> : path to the configuration file
• -p, --pid-file <path> : path to pid file (overrides the one provided in configuration file)
• -D, --no-daemon : do not daemonize
• -s, --sync-exit : handle exit signals
• -v, --version : print version and exit

Credits

(c) 2011, ZAO "Begun"

https://github.com/Begun/lizard

This software is licensed under the GNU LGPL. Please see the LICENSE file.