sliderule

The SlideRule Python API sliderule.py is used to access the services provided by the base SlideRule server. From Python, the module can be imported via:

import sliderule

source

sliderule.source(api, parm={}, stream=False, callbacks={}, path='/source')[source]

Perform API call to SlideRule service

Parameters

  • api (str) – name of the SlideRule endpoint

  • parm (dict) – dictionary of request parameters

  • stream (bool) – whether the request is a normal service or a stream service (see De-serialization for more details)

  • callbacks (dict) – record type callbacks (advanced use)

  • path (str) – path to api being requested

Returns

response data

Return type

dictionary

Examples

>>> import sliderule
>>> sliderule.set_url("slideruleearth.io")
>>> rqst = {
...     "time": "NOW",
...     "input": "NOW",
...     "output": "GPS"
... }
>>> rsps = sliderule.source("time", rqst)
>>> print(rsps)
{'time': 1300556199523.0, 'format': 'GPS'}

set_url

sliderule.set_url(url)[source]

Configure sliderule package with URL of service

Parameters

urls (str) – IP address or hostname of SlideRule service (note, there is a special case where the url is provided as a list of strings instead of just a string; when a list is provided, the client hardcodes the set of servers that are used to process requests to the exact set provided; this is used for testing and for local installations and can be ignored by most users)

Examples

>>> import sliderule
>>> sliderule.set_url("service.my-sliderule-server.org")

update_available_servers

sliderule.update_available_servers(desired_nodes=None, time_to_live=None)[source]

Manages the number of servers in the cluster. If the desired_nodes parameter is set, then a request is made to change the number of servers in the cluster to the number specified. In all cases, the number of nodes currently running in the cluster are returned - even if desired_nodes is set; subsequent calls to this function is needed to check when the current number of nodes matches the desired_nodes.

Parameters

  • desired_nodes (int) – the desired number of nodes in the cluster

  • time_to_live (int) – number of minutes for the desired nodes to run

Returns

  • int – number of nodes currently in the cluster

  • int – number of nodes available for work in the cluster

Examples

>>> import sliderule
>>> num_servers, max_workers = sliderule.update_available_servers(10)

set_verbose

sliderule.set_verbose(enable)[source]

Configure sliderule package for verbose logging

Parameters

enable (bool) – whether or not user level log messages received from SlideRule generate a Python log message

Examples

>>> import sliderule
>>> sliderule.set_verbose(True)

The default behavior of Python log messages is for them to be displayed to standard output. If you want more control over the behavior of the log messages being display, create and configure a Python log handler as shown below:

>>> # import packages
>>> import logging
>>> from sliderule import sliderule
>>> # Configure Logging
>>> sliderule_logger = logging.getLogger("sliderule.sliderule")
>>> sliderule_logger.setLevel(logging.INFO)
>>> # Create Console Output
>>> ch = logging.StreamHandler()
>>> ch.setLevel(logging.INFO)
>>> sliderule_logger.addHandler(ch)

set_max_errors

set_max_pending

set_rqst_timeout

sliderule.set_rqst_timeout(timeout)[source]

Sets the TCP/IP connection and reading timeouts for future requests made to sliderule servers. Setting it lower means the client will failover more quickly, but may generate false positives if a processing request stalls or takes a long time returning data. Setting it higher means the client will wait longer before designating it a failed request which in the presence of a persistent failure means it will take longer for the client to remove the node from its available servers list.

Parameters

timeout (tuple) – (<connection timeout in seconds>, <read timeout in seconds>)

Examples

>>> import sliderule
>>> sliderule.set_rqst_timeout((10, 60))

gps2utc

sliderule.gps2utc(gps_time, as_str=True, epoch=datetime.datetime(1980, 1, 6, 0, 0))[source]

Convert a GPS based time returned from SlideRule into a UTC time.

Parameters

  • gps_time (int) – number of seconds since GPS epoch (January 6, 1980)

  • as_str (bool) – if True, returns the time as a string; if False, returns the time as datatime object

  • epoch (datetime) – the epoch used in the conversion, defaults to GPS epoch (Jan 6, 1980)

Returns

UTC time (i.e. GMT, or Zulu time)

Return type

datetime

Examples

>>> import sliderule
>>> sliderule.gps2utc(1235331234)
'2019-02-27 19:34:03'

get_definition

sliderule.get_definition(rectype, fieldname)[source]

Get the underlying format specification of a field in a return record.

Parameters

  • rectype (str) – the name of the type of the record (i.e. “atl03rec”)

  • fieldname (str) – the name of the record field (i.e. “cycle”)

Returns

description of each field; see the sliderule.basictypes variable for different field types

Return type

dict

Examples

>>> import sliderule
>>> sliderule.set_url("slideruleearth.io")
>>> sliderule.get_definition("atl03rec", "cycle")
{'fmt': 'H', 'size': 2, 'nptype': <class 'numpy.uint16'>}