Trigger action API

Collaboration diagram for Trigger action API:

Modules
	Trigger action rate policy API
	Trigger action list API
	“Notify” trigger action API
	“Start recording session” trigger action API
	“Stop recording session” trigger action API
	“Rotate recording session snapshot” trigger action API
	“Take recording session snapshot” trigger action API
	“Increment map value” trigger action API

Enumerations
enum	lttng_action_status { LTTNG_ACTION_STATUS_OK , LTTNG_ACTION_STATUS_ERROR , LTTNG_ACTION_STATUS_UNKNOWN , LTTNG_ACTION_STATUS_INVALID , LTTNG_ACTION_STATUS_UNSET }
	Return type of trigger action API functions. More...
enum	lttng_action_type {   LTTNG_ACTION_TYPE_NOTIFY , LTTNG_ACTION_TYPE_START_SESSION , LTTNG_ACTION_TYPE_STOP_SESSION , LTTNG_ACTION_TYPE_ROTATE_SESSION ,   LTTNG_ACTION_TYPE_SNAPSHOT_SESSION , LTTNG_ACTION_TYPE_LIST , LTTNG_ACTION_TYPE_INCREMENT_MAP_VALUE , LTTNG_ACTION_TYPE_UNKNOWN }
	Trigger action type. More...

Functions
void	lttng_action_destroy (struct lttng_action *action)
	Destroys the trigger action action.
enum lttng_action_type	lttng_action_get_type (const struct lttng_action *action)
	Returns the type of the trigger action action.

Detailed Description

A trigger action is the part of a trigger which LTTng executes when its trigger condition is satisfied.

As of LTTng-tools 16.2, the following trigger actions are available:

Action type	Type enumerator	Creation function
Notify	LTTNG_ACTION_TYPE_NOTIFY	lttng_action_notify_create()
Start recording session	LTTNG_ACTION_TYPE_START_SESSION	lttng_action_start_session_create()
Stop recording session	LTTNG_ACTION_TYPE_STOP_SESSION	lttng_action_stop_session_create()
Rotate recording session snapshot	LTTNG_ACTION_TYPE_ROTATE_SESSION	lttng_action_rotate_session_create()
Take recording session snapshot	LTTNG_ACTION_TYPE_SNAPSHOT_SESSION	lttng_action_snapshot_session_create()
Increment map value	LTTNG_ACTION_TYPE_INCREMENT_MAP_VALUE	lttng_action_increment_map_value_create()

LTTng can execute more than one action when a trigger fires: create a trigger action list with lttng_action_list_create().

Get the type of a trigger condition with lttng_condition_get_type().

By default, LTTng executes the action of a trigger every time it fires. See Trigger action rate policy API to change the rate policy of a trigger action (every N times or once after N times). As of LTTng-tools 16.2, you cannot change the rate policy of an “increment map value” action: its effective rate policy is “every time”.

Destroy a trigger condition with lttng_condition_destroy().

Enumeration Type Documentation

lttng_action_status

enum lttng_action_status

Return type of trigger action API functions.

Enumerator
LTTNG_ACTION_STATUS_OK	Success.
LTTNG_ACTION_STATUS_ERROR	Error.
LTTNG_ACTION_STATUS_INVALID	Unsatisfied precondition.
LTTNG_ACTION_STATUS_UNSET	Not set.

lttng_action_type

enum lttng_action_type

Trigger action type.

Get the type of a trigger action with lttng_action_get_type().

Enumerator
LTTNG_ACTION_TYPE_NOTIFY	Notify.
LTTNG_ACTION_TYPE_START_SESSION	Start recording session.
LTTNG_ACTION_TYPE_STOP_SESSION	Stop recording session.
LTTNG_ACTION_TYPE_ROTATE_SESSION	Rotate recording session snapshot.
LTTNG_ACTION_TYPE_SNAPSHOT_SESSION	Take recording session snapshot.
LTTNG_ACTION_TYPE_LIST	Trigger action list.
LTTNG_ACTION_TYPE_INCREMENT_MAP_VALUE	Increment map value.
LTTNG_ACTION_TYPE_UNKNOWN	Unknown (error).

Function Documentation

lttng_action_destroy()

void lttng_action_destroy ( struct lttng_action *  action )

extern

Destroys the trigger action action.

Parameters

[in]

action

Trigger action to destroy. May be NULL.

lttng_action_get_type()

enum lttng_action_type lttng_action_get_type ( const struct lttng_action *  action )

extern

Returns the type of the trigger action action.

Parameters

[in]

action

Trigger action of which to get the type.

Returns

Type of action.

Precondition

• action is not NULL.