katsdptelstate 0.9

Getting Started

The simplest way to test out katsdptelstate is to use the in-memory backend. If you want to run a real Redis server you will need to install Redis (version 2.8.9 or newer) on a suitable machine on the network. For example, do this:

• macOS: brew install redis

• Ubuntu: apt-get install redis-server

Then pip install katsdptelstate and run a local redis-server. If you also want to load RDB files, do pip install katsdptelstate[rdb].

A Simple Example

import time
import katsdptelstate

# Connect to an actual Redis server via an endpoint or an URL
telstate = katsdptelstate.TelescopeState('localhost:6379')
telstate = katsdptelstate.TelescopeState('redis://localhost')
# Or use the in-memory backend (useful for testing)
telstate = katsdptelstate.TelescopeState()
# Load RDB file into Redis if katsdptelstate is installed with [rdb] option
telstate.load_from_file('dump.rdb')

# Attribute / dict style access returns the latest value
telstate.add('n_chans', 32768)
print(telstate.n_chans)  # -> 32768
print(telstate['n_chans'])  # -> 32768

# List all keys (attributes and sensors)
print(telstate.keys())  # -> ['n_chans']

# Sensors are timestamped underneath
st = time.time()
telstate.add('n_chans', 4096)
et = time.time()
telstate.add('n_chans', 16384)
# Time ranges can be used and are really fast
telstate.get_range('n_chans', st=st, et=et)  # -> [(4096, 1556112474.453495)]
# Add an item 10 seconds back
telstate.add('n_chans', 1024, ts=time.time() - 10)

# Attributes cannot be changed (only deleted)
telstate.add('no_change', 1234, immutable=True)
# Adding it again is OK as long as the value doesn't change
telstate.add('no_change', 1234, immutable=True)
# Simpler notation for setting attributes
telstate['no_change'] = 1234
# Will raise katsdptelstate.ImmutableKeyError
telstate['no_change'] = 456

# Create a new view with namespace 'ns' and standard underscore separator
view = telstate.view('ns')
# Insert a new attribute in this namespace and retrieve it
view['x'] = 1
print(view['x'])  # -> 1
print(view.prefixes)  # -> ('ns_', '')
print(view.keys())  # -> ['n_chans', 'no_change', 'ns_x']

0.9 (2020-05-25)

• Deprecate Python 2 support: this is the last release that will support Python 2 (#94)

• Remove get_message and send_message, which were never used (#89)

• Publish the documentation on https://katsdptelstate.readthedocs.io (#90)

• Disable pickles by default for security (#92)

0.8 (2019-05-06)

• The default encoding is now msgpack; warn on loading pickles (#75, #79)

• The default backend is now in-memory (#76)

• Add the ability to dump in-memory backend to an RDB file (#77)

• Construct from RDB file-like objects and Redis URLs (#80, #82)

• Report keys and prefixes to the user as strings (#73)

• Add IPython tab completion (#83)

• RDB reader and writer cleanup (#85, #86)

0.7 (2019-02-12)

• Introduce encodings and add msgpack encoding as alternative to pickle (#64, #65)

• Introduce backends and add in-memory backend as alternative to redis (#71, #72)

• Simplify setting attributes via __setitem__ (#68)

• Let keys be bytes internally, but allow specification as unicode strings (#63)

• The GitHub repository is now public as well

0.6 (2018-05-10)

• Initial release of katsdptelstate