Selection Policy

The SelectionManager is the owner of SelectionPolicies and will use them to execute sql queries to the database.

The SelectionManager has a 1-1 relationship with the CalibrationStore, new configurable policies can be injected into the manager from the tango interface using UpdateSelectionPolicy

SelectionManager(logger)	A SelectionManager.
SelectPreferred(logger, *args, **kwargs)	A SelectPreferred policy preferred.

This subpackage implements calibration store functionality for MCCS.

class SelectClosestInRange(logger: Logger, *args: Any, **kwargs: Any)

A SelectClosestInRange policy closest_in_range.

The most recent solution within a defined frequency tolerance.

>>>    "SELECT frequency_channel, "
>>>    "calibration_path, creation_time, station_id, preferred, "
>>>    "solution "
>>>    "FROM calibration_per_channel "
>>>    f"WHERE station_id = {station_id} "
>>>    f"AND frequency_channel >= {frequency_channel-self.frequency_tolerance} "
>>>    f"AND frequency_channel <= {frequency_channel+self.frequency_tolerance} "
>>>    "ORDER BY creation_time DESC "
>>>    "LIMIT 1"

configure(frequency_tolerance: int = 0, **kwargs: Any) → None

Configure the SelectClosestInRange policy.

Parameters:

• frequency_tolerance – the absolute frequency tolerance.

• kwargs – kwargs

generate_sql(station_id: int, frequency_channel: int, **kwargs: Any) → tuple[str, tuple]

Return an sql query with parameterized inputs.

Parameters:

• station_id – The id of the station we want a solution for.

• frequency_channel – The current frequency channel.

• kwargs – kwargs

Returns:

a sql query.

class SelectPreferred(logger: Logger, *args: Any, **kwargs: Any)

A SelectPreferred policy preferred.

The most recent solution within a defined frequency tolerance with the field preferred == TRUE is chosen. If none defined as preferred, no solution is returned.

>>>    "SELECT frequency_channel, "
>>>    "calibration_path, creation_time, station_id, preferred, "
>>>    "solution "
>>>    "FROM calibration_per_channel "
>>>    f"WHERE station_id = {station_id} "
>>>    f"AND frequency_channel >= {frequency_channel-self.frequency_tolerance} "
>>>    f"AND frequency_channel <= {frequency_channel+self.frequency_tolerance} "
>>>    "AND preferred = TRUE "
>>>    "ORDER BY creation_time DESC "
>>>    "LIMIT 1"

configure(frequency_tolerance: int = 0, **kwargs: Any) → None

Configure the SelectPreferred policy.

Parameters:

• frequency_tolerance – the absolute frequency tolerance.

• kwargs – kwargs

generate_sql(station_id: int, frequency_channel: int, **kwargs: Any) → tuple[str, tuple]

Return an sql query with parameterized inputs.

Parameters:

• station_id – The id of the station we want a solution for.

• frequency_channel – The current frequency channel.

• kwargs – kwargs

Returns:

a sql query.

class SelectionManager(logger: Logger)

A SelectionManager.

__init__(logger: Logger) → None

Initialise a new SelectionManager.

Parameters:

logger – A logger for information purposes.

check_calibration_id(connection: Any, cal_id: str) → bool

Check if the given cal id is in the database already.

Parameters:

• connection – the database connection.

• cal_id – the cal ID to check.

Returns:

True if the cal ID is already in the database

get_calibration_ids(connection: Any) → list[str]

Get all calibration_ids.

Parameters:

connection – the database connection.

Returns:

A list of all calibration_ids

get_solution(connection: Any, **kwargs: Any) → list[float]

Get a solution using the loaded SelectionPolicy.

This will return a solution from a query set by the loaded SelectionPolicy

Parameters:

• connection – the database connection.

• kwargs – kwargs to feed the selection policy

Returns:

the solution or an empty list.

Raises:

ValueError – then there is no configured policy to use.

get_solution_from_cal_id(connection: Any, channel_id: int, calibration_id: str) → list[float]

Get a solution from the calibration and station ids.

Parameters:

• connection – the database connection.

• channel_id – The channel id.

• calibration_id – The calibration id.

Returns:

the solution or an empty list.

property has_policy: bool

Return whether policy is defined.

Returns:

True if policy is not None.

property policy: str

Return the policy.

Returns:

the selection policy.

property policy_description: str

Return details about the policy description.

Returns:

information about the selection policy.

update_policy(policy: SelectPreferred | SelectClosestInRange) → None

Set a new policy.

Parameters:

policy – the sql to use.