databroker.Header.config_data

Header.config_data(self, device_name)[source]

Extract device configuration data from Event Descriptors.

This refers to the data obtained from device.read_configuration().

See example below. The result is structed as a […deep breath…] dictionary of lists of dictionaries because:

  • The device might have been read in multiple event streams (‘primary’, ‘baseline’, etc.). Each stream name is a key in the outer dictionary.

  • The configuration is typically read once per event stream, but in general may be read multiple times if the configuration is changed mid-stream. Thus, a list is needed.

  • Each device typically produces multiple configuration fields (‘exposure_time’, ‘period’, etc.). These are the keys of the inner dictionary.

Parameters
device_namestring

device name (originally obtained from the name attribute of some readable Device)

Returns
resultdict

mapping each stream name (such as ‘primary’ or ‘baseline’) to a list of data dictionaries

Examples

Get the device configuration recorded for the device named ‘eiger’.

>>> h.config_data('eiger')
{'primary': [{'exposure_time': 1.0}]}

Assign the exposure time to a variable.

>>> exp_time = h.config_data('eiger')['primary'][0]['exposure_time']

How did we know that 'eiger' was a valid argument? We can query for the complete list of device names:

>>> h.devices()
{'eiger', 'cs700'}