class SDLWrapper:
"""
- This is a wrapper around the SDL Python interface.
+ Provides convenient wrapper methods for using the SDL Python interface.
+ Optionally uses msgpack for binary (de)serialization:
+ see https://msgpack.org/index.html
- We do not embed the below directly in the Xapp classes because
- this SDL wrapper is useful for other python apps, for example A1
- Mediator uses this verbatim. Therefore, we leave this here as a
- seperate instantiable object so it can be used outside of xapps
- too. One could argue this get moved into *sdl itself*.
-
- We currently use msgpack for binary (de)serialization:
- https://msgpack.org/index.html
+ Published as a standalone module (and kept separate from the Xapp
+ framework classes) so these features can be used outside Xapps.
"""
def __init__(self, use_fake_sdl=False):
Parameters
----------
- use_fake_sdl: bool
- if this is True (default: False), then SDLs "fake dict
- backend" is used, which is very useful for testing since
- it allows you to use SDL without any SDL or Redis deployed at
- all. This can be used while developing your xapp, and also
- for monkeypatching during unit testing (e.g., the xapp
- framework unit tests do this).
+ use_fake_sdl: bool (optional, default False)
+ if this is True, then use SDL's in-memory backend,
+ which is very useful for testing since it allows use
+ of SDL without a running SDL or Redis instance.
+ This can be used while developing an xapp and also
+ for monkeypatching during unit testing; e.g., the xapp
+ framework unit tests do this.
"""
if use_fake_sdl:
self._sdl = SyncStorage(fake_db_backend="dict")
def set(self, ns, key, value, usemsgpack=True):
"""
- sets a key
+ Stores a key-value pair,
+ optionally serializing the value to bytes using msgpack.
TODO: discuss whether usemsgpack should *default* to True or
False here. This seems like a usage statistic question (that we
don't have enough data for yet). Are more uses for an xapp to
write/read their own data, or will more xapps end up reading data
- written by some other thing? I think it's too early to know
- this. So we go with True as the very first user of this, a1, does
- this. I'm open to changing this default to False later with
- evidence.
+ written by some other thing? I think it's too early to know.
Parameters
----------
ns: string
- the sdl namespace
+ SDL namespace
key: string
- the sdl key
+ SDL key
value:
- if usemsgpack is True, value can be anything serializable by msgpack
- if usemsgpack is False, value must be bytes
- usemsgpack: boolean (optional)
- determines whether the value is serialized using msgpack
+ Object or byte array to store. See the `usemsgpack` parameter.
+ usemsgpack: boolean (optional, default is True)
+ Determines whether the value is serialized using msgpack before storing.
+ If usemsgpack is True, the msgpack function `packb` is invoked
+ on the value to yield a byte array that is then sent to SDL.
+ Stated differently, if usemsgpack is True, the value can be anything
+ that is serializable by msgpack.
+ If usemsgpack is False, the value must be bytes.
"""
if usemsgpack:
- self._sdl.set(ns, {key: msgpack.packb(value, use_bin_type=True)})
- else:
- self._sdl.set(ns, {key: value})
+ value = msgpack.packb(value, use_bin_type=True)
+ self._sdl.set(ns, {key: value})
+
+ def set_if(self, ns, key, old_value, new_value, usemsgpack=True):
+ """
+ Conditionally modify the value of a key if the current value in data storage matches the
+ user's last known value.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ key: string
+ SDL key
+ old_value:
+ Lask known object or byte array. See the `usemsgpack` parameter.
+ new_value:
+ Object or byte array to be written. See the `usemsgpack` parameter.
+ usemsgpack: boolean (optional, default is True)
+ Determines whether the value is serialized using msgpack before storing.
+ If usemsgpack is True, the msgpack function `packb` is invoked
+ on the value to yield a byte array that is then sent to SDL.
+ Stated differently, if usemsgpack is True, the value can be anything
+ that is serializable by msgpack.
+ If usemsgpack is False, the value must be bytes.
+
+ Returns
+ -------
+ bool
+ True for successful modification, false if the user's last known data did not
+ match the current value in data storage.
+ """
+ if usemsgpack:
+ old_value = msgpack.packb(old_value, use_bin_type=True)
+ new_value = msgpack.packb(new_value, use_bin_type=True)
+ return self._sdl.set_if(ns, key, old_value, new_value)
+
+ def set_if_not_exists(self, ns, key, value, usemsgpack=True):
+ """
+ Write data to SDL storage if key does not exist.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ key: string
+ SDL key
+ value:
+ Object or byte array to store. See the `usemsgpack` parameter.
+ usemsgpack: boolean (optional, default is True)
+ Determines whether the value is serialized using msgpack before storing.
+ If usemsgpack is True, the msgpack function `packb` is invoked
+ on the value to yield a byte array that is then sent to SDL.
+ Stated differently, if usemsgpack is True, the value can be anything
+ that is serializable by msgpack.
+ If usemsgpack is False, the value must be bytes.
+
+ Returns
+ -------
+ bool
+ True for successful modification, false if the user's last known data did not
+ match the current value in data storage.
+ """
+ if usemsgpack:
+ value = msgpack.packb(value, use_bin_type=True)
+ return self._sdl.set_if_not_exists(ns, key, value)
def get(self, ns, key, usemsgpack=True):
"""
- get a key
+ Gets the value for the specified namespace and key,
+ optionally deserializing stored bytes using msgpack.
Parameters
----------
ns: string
- the sdl namespace
+ SDL namespace
key: string
- the sdl key
- usemsgpack: boolean (optional)
- if usemsgpack is True, the value is deserialized using msgpack
- if usemsgpack is False, the value is returned as raw bytes
+ SDL key
+ usemsgpack: boolean (optional, default is True)
+ If usemsgpack is True, the byte array stored by SDL is deserialized
+ using msgpack to yield the original object that was stored.
+ If usemsgpack is False, the byte array stored by SDL is returned
+ without further processing.
Returns
-------
- None (if not exist) or see above; depends on usemsgpack
+ Value
+ See the usemsgpack parameter for an explanation of the returned value type.
+ Answers None if the key is not found.
"""
+ result = None
ret_dict = self._sdl.get(ns, {key})
if key in ret_dict:
+ result = ret_dict[key]
if usemsgpack:
- return msgpack.unpackb(ret_dict[key], raw=False)
- return ret_dict[key]
+ result = msgpack.unpackb(result, raw=False)
+ return result
- return None
+ def find_keys(self, ns, prefix):
+ """
+ Find all keys matching search pattern under the namespace.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ prefix: string
+ Key search pattern
+
+ Returns
+ -------
+ keys: list
+ A list of found keys.
+ """
+ return self._sdl.find_keys(ns, f"{prefix}*")
def find_and_get(self, ns, prefix, usemsgpack=True):
"""
- get all k v pairs that start with prefix
+ Gets all key-value pairs in the specified namespace
+ with keys that start with the specified prefix,
+ optionally deserializing stored bytes using msgpack.
Parameters
----------
ns: string
- the sdl namespace
- key: string
- the sdl key
+ SDL namespace
prefix: string
- the prefix
- usemsgpack: boolean (optional)
- if usemsgpack is True, the value returned is a dict where each value has been deserialized using msgpack
- if usemsgpack is False, the value returned is as a dict mapping keys to raw bytes
+ the key prefix
+ usemsgpack: boolean (optional, default is True)
+ If usemsgpack is True, every byte array stored by SDL is deserialized
+ using msgpack to yield the original value that was stored.
+ If usemsgpack is False, every byte array stored by SDL is returned
+ without further processing.
Returns
-------
- {} (if no keys match) or see above; depends on usemsgpack
+ Dictionary of key-value pairs
+ Each key has the specified prefix.
+ See the usemsgpack parameter for an explanation of the returned value types.
+ Answers an empty dictionary if no keys matched the prefix.
"""
# note: SDL "*" usage is inconsistent with real python regex, where it would be ".*"
- ret_dict = self._sdl.find_and_get(ns, "{0}*".format(prefix))
+ ret_dict = self._sdl.find_and_get(ns, f"{prefix}*")
if usemsgpack:
- return {k: msgpack.unpackb(v, raw=False) for k, v in ret_dict.items()}
+ ret_dict = {k: msgpack.unpackb(v, raw=False) for k, v in ret_dict.items()}
return ret_dict
def delete(self, ns, key):
"""
- delete a key
+ Deletes the key-value pair with the specified key in the specified namespace.
Parameters
----------
ns: string
- the sdl namespace
+ SDL namespace
key: string
- the sdl key
+ SDL key
"""
self._sdl.remove(ns, {key})
+ def delete_if(self, ns, key, value, usemsgpack=True):
+ """
+ Conditionally remove data from SDL storage if the current data value matches the user's
+ last known value.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ key: string
+ SDL key
+ value:
+ Object or byte array to store. See the `usemsgpack` parameter.
+ usemsgpack: boolean (optional, default is True)
+ Determines whether the value is serialized using msgpack before storing.
+ If usemsgpack is True, the msgpack function `packb` is invoked
+ on the value to yield a byte array that is then sent to SDL.
+ Stated differently, if usemsgpack is True, the value can be anything
+ that is serializable by msgpack.
+ If usemsgpack is False, the value must be bytes.
+
+ Returns
+ -------
+ bool
+ True if successful removal, false if the user's last known data did not match the
+ current value in data storage.
+ """
+ if usemsgpack:
+ value = msgpack.packb(value, use_bin_type=True)
+ return self._sdl.remove_if(ns, key, value)
+
+ def add_member(self, ns, group, member, usemsgpack=True):
+ """
+ Add new members to a SDL group under the namespace.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ group: string
+ group name
+ member:
+ member to be added
+ usemsgpack: boolean (optional, default is True)
+ Determines whether the member is serialized using msgpack before storing.
+ If usemsgpack is True, the msgpack function `packb` is invoked
+ on the member to yield a byte array that is then sent to SDL.
+ Stated differently, if usemsgpack is True, the member can be anything
+ that is serializable by msgpack.
+ If usemsgpack is False, the member must be bytes.
+ """
+ if usemsgpack:
+ member = msgpack.packb(member, use_bin_type=True)
+ self._sdl.add_member(ns, group, {member})
+
+ def remove_member(self, ns, group, member, usemsgpack=True):
+ """
+ Remove members from a SDL group.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ group: string
+ group name
+ member:
+ member to be removed
+ usemsgpack: boolean (optional, default is True)
+ Determines whether the member is serialized using msgpack before storing.
+ If usemsgpack is True, the msgpack function `packb` is invoked
+ on the member to yield a byte array that is then sent to SDL.
+ Stated differently, if usemsgpack is True, the member can be anything
+ that is serializable by msgpack.
+ If usemsgpack is False, the member must be bytes.
+ """
+ if usemsgpack:
+ member = msgpack.packb(member, use_bin_type=True)
+ self._sdl.remove_member(ns, group, {member})
+
+ def remove_group(self, ns, group):
+ """
+ Remove a SDL group along with its members.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ group: string
+ group name to remove
+ usemsgpack: boolean (optional, default is True)
+ Determines whether the member is serialized using msgpack before storing.
+ If usemsgpack is True, the msgpack function `packb` is invoked
+ on the member to yield a byte array that is then sent to SDL.
+ Stated differently, if usemsgpack is True, the member can be anything
+ that is serializable by msgpack.
+ If usemsgpack is False, the member must be bytes.
+ """
+ self._sdl.remove_group(ns, group)
+
+ def get_members(self, ns, group, usemsgpack=True):
+ """
+ Get all the members of a SDL group.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ group: string
+ group name to retrive
+ usemsgpack: boolean (optional, default is True)
+ Determines whether the member is serialized using msgpack before storing.
+ If usemsgpack is True, the msgpack function `packb` is invoked
+ on the member to yield a byte array that is then sent to SDL.
+ Stated differently, if usemsgpack is True, the member can be anything
+ that is serializable by msgpack.
+ If usemsgpack is False, the member must be bytes.
+
+ Returns
+ -------
+ Set[str] or Set[bytes]
+ A set of the members of the group.
+ None
+ """
+ ret_set = self._sdl.get_members(ns, group)
+ if usemsgpack:
+ ret_set = {msgpack.unpackb(m, raw=False) for m in ret_set}
+ return ret_set
+
+ def is_member(self, ns, group, member, usemsgpack=True):
+ """
+ Validate if a given member is in the SDL group.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ group: string
+ group name
+ member:
+ member to validate
+ usemsgpack: boolean (optional, default is True)
+ Determines whether the member is serialized using msgpack before storing.
+ If usemsgpack is True, the msgpack function `packb` is invoked
+ on the member to yield a byte array that is then sent to SDL.
+ Stated differently, if usemsgpack is True, the member can be anything
+ that is serializable by msgpack.
+ If usemsgpack is False, the member must be bytes.
+
+ Returns
+ -------
+ bool
+ True if member was in the group, false otherwise.
+ """
+ if usemsgpack:
+ member = msgpack.packb(member, use_bin_type=True)
+ return self._sdl.is_member(ns, group, member)
+
+ def group_size(self, ns, group):
+ """
+ Return the number of members in a group.
+ If the group does not exist, value 0 is returned.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ group: string
+ group name to retrive size
+ usemsgpack: boolean (optional, default is True)
+ Determines whether the member is serialized using msgpack before storing.
+ If usemsgpack is True, the msgpack function `packb` is invoked
+ on the member to yield a byte array that is then sent to SDL.
+ Stated differently, if usemsgpack is True, the member can be anything
+ that is serializable by msgpack.
+ If usemsgpack is False, the member must be bytes.
+
+ Returns
+ -------
+ int
+ Number of members in a group.
+ """
+ return self._sdl.group_size(ns, group)
+
+ def set_and_publish(self, ns, channel, event, key, value, usemsgpack=True):
+ """
+ Publish event to channel after writing data.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ channel: string
+ channel to publish event
+ event: string
+ published message
+ key: string
+ SDL key
+ value:
+ Object or byte array to store. See the `usemsgpack` parameter.
+ usemsgpack: boolean (optional, default is True)
+ Determines whether the value is serialized using msgpack before storing.
+ If usemsgpack is True, the msgpack function `packb` is invoked
+ on the value to yield a byte array that is then sent to SDL.
+ Stated differently, if usemsgpack is True, the value can be anything
+ that is serializable by msgpack.
+ If usemsgpack is False, the value must be bytes.
+ """
+ if usemsgpack:
+ value = msgpack.packb(value, use_bin_type=True)
+ self._sdl.set_and_publish(ns, {channel: event}, {key: value})
+
+ def set_if_and_publish(self, ns, channel, event, key, old_value, new_value, usemsgpack=True):
+ """
+ Publish event to channel after conditionally modifying the value of a key if the
+ current value in data storage matches the user's last known value.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ channel: string
+ channel to publish event
+ event: string
+ published message
+ key: string
+ SDL key
+ old_value:
+ Lask known object or byte array. See the `usemsgpack` parameter.
+ new_value:
+ Object or byte array to be written. See the `usemsgpack` parameter.
+ usemsgpack: boolean (optional, default is True)
+ Determines whether the old_value & new_value is serialized using msgpack before storing.
+ If usemsgpack is True, the msgpack function `packb` is invoked
+ on the old_value & new_value to yield a byte array that is then sent to SDL.
+ Stated differently, if usemsgpack is True, the old_value & new_value can be anything
+ that is serializable by msgpack.
+ If usemsgpack is False, the old_value & new_value must be bytes.
+
+ Returns
+ -------
+ bool
+ True for successful modification, false if the user's last known data did not
+ match the current value in data storage.
+ """
+ if usemsgpack:
+ old_value = msgpack.packb(old_value, use_bin_type=True)
+ new_value = msgpack.packb(new_value, use_bin_type=True)
+ return self._sdl.set_if_and_publish(ns, {channel: event}, key, old_value, new_value)
+
+ def set_if_not_exists_and_publish(self, ns, channel, event, key, value, usemsgpack=True):
+ """
+ Publish event to channel after writing data to SDL storage if key does not exist.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ channel: string
+ channel to publish event
+ event: string
+ published message
+ key: string
+ SDL key
+ value:
+ Object or byte array to store. See the `usemsgpack` parameter.
+ usemsgpack: boolean (optional, default is True)
+ Determines whether the value is serialized using msgpack before storing.
+ If usemsgpack is True, the msgpack function `packb` is invoked
+ on the value to yield a byte array that is then sent to SDL.
+ Stated differently, if usemsgpack is True, the value can be anything
+ that is serializable by msgpack.
+ If usemsgpack is False, the value must be bytes.
+
+ Returns
+ -------
+ bool
+ True if key didn't exist yet and set operation was executed, false if key already
+ existed and thus its value was left untouched.
+ """
+ if usemsgpack:
+ value = msgpack.packb(value, use_bin_type=True)
+ return self._sdl.set_if_not_exists_and_publish(ns, {channel: event}, key, value)
+
+ def remove_and_publish(self, ns, channel, event, key):
+ """
+ Publish event to channel after removing data.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ channel: string
+ channel to publish event
+ event: string
+ published message
+ key: string
+ SDL key
+ """
+ self._sdl.remove_and_publish(ns, {channel: event}, {key})
+
+ def remove_if_and_publish(self, ns, channel, event, key, value, usemsgpack=True):
+ """
+ Publish event to channel after removing key and its data from database if the
+ current data value is expected one.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ channel: string
+ channel to publish event
+ event: string
+ published message
+ key: string
+ SDL key
+ value:
+ Object or byte array to store. See the `usemsgpack` parameter.
+ usemsgpack: boolean (optional, default is True)
+ Determines whether the value is serialized using msgpack before storing.
+ If usemsgpack is True, the msgpack function `packb` is invoked
+ on the value to yield a byte array that is then sent to SDL.
+ Stated differently, if usemsgpack is True, the value can be anything
+ that is serializable by msgpack.
+ If usemsgpack is False, the value must be bytes.
+
+ Returns
+ -------
+ bool
+ True if successful removal, false if the user's last known data did not match the
+ current value in data storage.
+ """
+ if usemsgpack:
+ value = msgpack.packb(value, use_bin_type=True)
+ return self._sdl.remove_if_and_publish(ns, {channel: event}, key, value)
+
+ def remove_all_and_publish(self, ns, channel, event):
+ """
+ Publish event to channel after removing all keys under the namespace.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ channel: string
+ channel to publish event
+ event: string
+ published message
+ """
+ self._sdl.remove_all_and_publish(ns, {channel: event})
+
+ def subscribe_channel(self, ns, cb, channel):
+ """
+ Subscribes the client to the specified channels.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ cb:
+ A function that is called when an event on channel is received.
+ channel: string
+ channel to subscribe
+ """
+ self._sdl.subscribe_channel(ns, cb, {channel})
+
+ def unsubscribe_channel(self, ns, channel):
+ """
+ unsubscribe_channel removes subscription from one or several channels.
+
+ Parameters
+ ----------
+ ns: string
+ SDL namespace
+ channel: string
+ channel to unsubscribe
+ """
+ self._sdl.unsubscribe_channel(ns, {channel})
+
+ def start_event_listener(self):
+ """
+ start_event_listener creates an event loop in a separate thread for handling
+ events from subscriptions. The registered callback function will be called
+ when an event is received.
+ """
+ self._sdl.start_event_listener()
+
+ def handle_events(self):
+ """
+ handle_events is a non-blocking function that returns a tuple containing channel
+ name and a list of message(s) received from an event. The registered callback
+ function will still be called when an event is received.
+
+ This function is called if SDL user decides to handle notifications in its own
+ event loop. Calling this function after start_event_listener raises an exception.
+ If there are no notifications, these returns None.
+
+ Returns
+ -------
+ Tuple:
+ (channel: str, message: list of str)
+ """
+ return self._sdl.handle_events()
+
def healthcheck(self):
"""
- checks if the sdl connection is healthy
+ Checks if the sdl connection is healthy.
Returns
-------
Code Review / ric-plt / xapp-frame-py.git / blobdiff