TMC Common EventManager

1. EventManager

This module contains event management functionality.

class ska_tmc_common.v2.event_manager.EventManager(component_manager: TmcComponentManager | TmcLeafNodeComponentManager, subscription_configuration: Optional[dict[str, list]] = None, logger: logging.Logger = <Mock name='mock()' id='133592083038560'>, stateless: bool = True, event_subscription_check_period: int = 1, event_error_max_count: int = 10, status_update_callback: Optional[Callable] = None, maximum_status_queue_size: int = 50)

This class provides necessary functions to manage event subscriptions.

property pending_configuration: dict[str, list]

This method provides the pending configuration.

Returns:

This method returns the pending subscription configurations.

Return type:

dict[str, list]

property stateless_flag: bool

This method provides the stateless flag for event subscription.

Returns:

This returns the value of stateless flag.

Return type:

bool

property subscription_configruation: dict[str, list]

This method provides the subscription configuration provided.

Returns:

This method returns the subscription configuration.

Return type:

dict[str, list]

property device_subscriptions: dict[str, dict[int, bool]] | dict

This method provides the instanc of device subscriptions

dictionary.

Returns:

This method returns the value of device subscriptions variable.

Return type:

dict[str, dict[int, bool]],dict

property device_errors_tracker: None

This method returns dictionary with device errors.

init_timeout(thread_id: int) → None

This method initializes timeout flag for the provided thread id.

Parameters:

thread_id (int) – thread id

set_timeout(thread_id: int) → None

Sets the timeout flag for provided the thread id.

Parameters:

thread_id (int) – thread id

start_timer(name: str, thread_id: int, timeout: int = 1000) → None

This method starts a timer thread which updates timeout flag

once it is completed.

Parameters:

• name (str) – The name of the the timer thread.

• timeout (int) – Timeout till when the subscriptions will be retired.

• thread_id (int) – thread id

stop_timer(name: str) → None

This method stops the timer thread running.

Parameters:

name (str) – The name of the timer thread which needs to be stopped.

start_event_subscription(subscription_configuration: dict[str, list] | None = None, timeout: int = 1000) → int

This method starts a thread to subscribe events.

Parameters:

• subscription_configuration (dict[str, list], optional) – This is optional parameter, if user wants to start thread with different configuration.

• timeout (int) – The duration till when it will try to subscribe, defaults to 1000 seconds.

Returns:

Returns the thread id

Return type:

int

init_unsubscription_cancellation(thread_id: int) → None

This method initializes the unsubscription cancellation dictionary. :param thread_id: thread id :type thread_id: int

cancel_unsubscription_thread(thread_id: int) → None

This method canceles the unsubscription thread.

Parameters:

thread_id (int) – thread id

unsubscribe_event_async(device_name: str, attribute_names: list | None = None) → int

This method unsubcribes the events aysnchronous using threads of the specified device name or some attributes under that device name.

Parameters:

• device_name (str) – This variable consists of device name whose events needs to be unsubscribed.

• attribute_names (list, optional) – This list contains names of specific attributes that needs to be unsubscribed.

Returns:

Returns the thread id

Return type:

int

unsubscribe_events(device_name: str, attribute_names: list | None = None) → None

This method unsubcribes the events of the specified device name or some attributes under that device name.

Parameters:

• device_name (str) – This variable consists of device name whose events needs to be unsubscribed.

• attribute_names (list, optional) – This list contains names of specific attributes that needs to be unsubscribed.

init_device_subscriptions(device_name: str) → None

Initialisation of device configuration dictionary.

Parameters:

device_name (str) – device name.

update_device_subscriptions(device_name: str, attribute_name: str | None = None, subscription_id: int | None = None, is_subscription_completed: bool | None = None) → None

This method updates device_subscriptions dictionary with the provided values.

Parameters:

• device_name (str) – tango device FQDN.

• attribute_name (str, optional) – Attribute name under provided device.

• subscription_id (int, optional) – Subscription ID of attribute after successful completion.

• is_subscription_completed (bool, optional) – This flag is set once all the subscription is completed.

get_device_proxy(device_name: str) → tango.DeviceProxy

This method creates device proxy for the provided device name.

Parameters:

device_name (str) – Tango device FQDN.

Returns:

Returns device proxy

Return type:

tango.DeviceProxy

cancel_subscription_thread(thread_id: int)

This method provides a mechanism to cancel the event subscription thread.

Parameters:

thread_id (int) – Thread id to be stopped

subscribe_events(subscription_configuration: dict[str, list], timeout: int = 1000) → None

This functions utilises the subscription configuration provided and subscribes to the attributes present in them. The function updates device_subscriptions dictionary with the details of sucess and failure.

Parameters:

• subscription_configuration (dict[str, list]) – The variable contains the detail of devices and their attributes to be subscribed. For Example: {“device_name”:[“attribute1”,”attribute2”]}.

• timeout (int) – The duration till when it will try to subscribe, defaults to 1000 seconds

remove_subscribed_devices(subscription_configuration: dict) → None

This method removes the devices from the configuration data.

Parameters:

subscription_configuration (dict) – This parameter contains the detail of devices and their attributes to be subscribed.

subscribe_pending_events(device_name: str)

This method checks for pending subscriptions for the device.

Parameters:

device_name (str) – tango device FQDN.

device_avaiability_callback(device_name: str) → None

This method is called once device is available back again to subscribe events if it that is pending.

Parameters:

device_name (str) – tango device FQDN which is available again.

get_device_and_attribute_name(attribute_fqdn: str) → tuple[str]

This method provides device and attribute name.

Parameters:

attribute_fqdn (str) – Full attribute FQDN from event data.

Returns:

Returns device name and attribue name

Return type:

tuple[str]

handle_event_error(event: tango.EventData) → None

This method handles the event error by tracking

Parameters:

event (tango.EventData) – change event data with error.

check_and_handle_event_error(event: tango.EventData) → bool

Checks event error and handles the API timeout error if it persists.

Parameters:

event (tango.EventData) – Change event data

Returns:

Returns True if event data has error, else returns False.s

Return type:

bool

update_status_queue(status: str) → None

This method updates status queue.

Parameters:

status (str) – The status message to update.