VILLASnode/doc/Development.md

Development

Developement is currently coordinated by Steffen Vogel stvogel@eonerc.rwth-aachen.de using GitHub. Please feel free to submit pull requests or bug reports.

Shared library: libvillas

VILLASnode is split into a shared library called libvillas and a couple of executables (villas-server, villas-pipe, villas-test, villas-signal) which are linked agains the library.

Extensibilty

There are two main places where VILLASnode can easily extended:

New node-type

REGISTER_NODE_TYPE(struct node_type *vt)

New hook functions

/** The type of a hook defines when a hook will be exectuted. This is used as a bitmask. */
enum hook_type {
	HOOK_PATH_START		= 1 << 0, /**< Called whenever a path is started; before threads are created. */

[...]

	HOOK_ASYNC		= 1 << 6, /**< Called asynchronously with fixed rate (see path::rate). */

	HOOK_PERIODIC		= 1 << 7, /**< Called periodically. Period is set by global 'stats' option in the configuration file. */

	/** @{ Classes of hooks */
	/** Internal hooks are mandatory. */
	HOOK_INTERNAL		= 1 << 16,
	/** All hooks */
	HOOK_ALL		= HOOK_INTERNAL - 1
	/** @} */
};

typedef int (*hook_cb_t)(struct path *p, struct hook *h, int when);

REGISTER_HOOK(char *name, int priority, hook_cb_t cb, enum hook_type when)