Ideas » History » Revision 6
Revision 5 (icy, 2010-06-05 13:43) → Revision 6/7 (stbuehler, 2010-09-21 13:52)
h1. Ideas
{{>toc}}
h2. Generic things
* Use ragel for parser generation
* Kick automake, probably use cmake instead
* Split off nice tools into separate trees (spawn-fcgi, fcgi-stat-accel)
* Use glib2 for containers and other things (modules, logging, ...?)
* Never use global variables. Never!
* Replace @docroot@ action with vhost.pattern plus allow cascading (list of patterns)
* Allow dynamic logfiles by passing logfile path to logthread instead of logpointer
h2. Get hackers and companies in touch
* http://www.cherokee-project.com/contribute.html - Bounty Hunting, get a company to spent a few bucks on things they want and ask community to write a module or extension and earn the money, nice idea! Users may submit their patches/modules and submit it to the devs, who then decide what gets implemented and who wins the price.
h2. Angel
* should perhaps use a separate config file
** manages define sockets / ssl options there? so sockets are maintained by angel for graceful restart restart?
* plugins (e.g. for fcgi spawning)
* perhaps a thread for error logging so error messages do not overlap?
h2. Config structure
* Generic backend
* Old config style frontend
* Lua frontend
* Linear request handling without confusing conditional blocks (still with conditionals of course)
* A nice interface to load/unload additional addtional config options (e.g. for sql-vhosts)
* Better interface for asynchronous config handling (again for sql vhosts)
h3. Options
> struct option
We have some different structures for options:
* Boolean (gboolean)
* Integer (gint)
* String (GString*)
* Array (GArray*) - an ordered list of sub options
* Hashtable (GHashTable*) - mapping from strings to sub options
For some things like rewrite we used associate arrays till now we could use an array of (key, value) pairs, perhaps use a special syntax for that ( "abc": "xyz" for ordered key-value pairs instead of "abc" => "xyz" for hashtables).
h3. Internal options
Every module can define a list of options (identified by name like "debug.log-something"). For each option there is a gpointer entry in a per connection table, in which the module can find the needed value by an index.
The definition for a option includes:
* Name
* Type (the same values as for option + perhaps a value for "custom")
* Two functions: parse_option and free_option (see below)
Two ideas for the index:
* Modules register every option manually and save a returned index in there plugin structure.
* Modules define a list of options and use a module-base-index (from plugin structure) + the local index for there list.
As it may be very useful for a module to have more than a "option struct", e.g. to safe filedescriptors (access.log), so we register every possible option with an option-specific parser. The default is to just use the value from the option struct.
This parser returns a gpointer, which will be put in the corresponding place in the connection table if it the options gets set.
To enable unloading of options there is also an free_option func which should release the memory.
h3. Actions
In the current lighttpd versions options are used to control which backend handles a request - this often depended on the order of loaded modules and some other things only a few people knew (or knew where to find).
We want to replace this with "actions": we explicitly call some functions and know what they will do.
There are some different types of action:
* Set config option
* Execute list of actions sublist
* If conditional is true execute subaction sublist
* call a special handler (provided by some module)
* call a backend balancer (provided by some module)
every action returns one of the following codes:
* ERROR - an internal error, stops connection handling
* GO_ON - nothing special happened
* COMEBACK BREAK - come back later, remember current position we finished a step like doc-root finding and want to skip other doc-root handling actions
* FINISHED - we now know how to handle the request. stop config handling here
* WAIT_FOR_EVENT - wait for vrequest wakeup (li_vrequest_joblist_append), come back later, remember current position
BREAK breaks all sublist handling until a "special" list is hit; the simple config will have hardcoded special lists, the lua will have dynamically ones.