Tessera

mosaic.core.tessera.tessera(*args, **cmd_config)

Decorator that transforms a standard class into a tessera-capable class.

The resulting class can still be instantiated as usual Klass(...), which will generate a standard local instance, or onto the mosaic runtime Klass.remote(...), which will instantiate the class in a remote endpoint and return a proxy to the user.

A mosaic Parameter can also be instantiated by using Klass.parameter(...).

TODO - Better explanations and more examples.

Returns

Return type

Enriched class

Examples

>>> @tessera
>>> class Klass:
>>>     def __init__(self, value):
>>>         self.value = value
>>>
>>>     def add(self, other):
>>>         self.value += other
>>>         return self.value
>>>
>>> # We can still generate a standard local instance
>>> local_instance = Klass(10)
>>>
>>> # but also a remote instance by invoking remote.
>>> remote_proxy = Klass.remote(10)
>>>
>>> # The resulting proxy can be used to call the instance methods,
>>> task = remote_proxy.add(5)
>>> # which will return immediately.
>>>
>>> # We can do some work while the remote method is executed
>>> # and then wait for it to end
>>> await task
>>>
>>> # We can retrieve the result of the task invoking result on the task
>>> await task.result()
15

class mosaic.core.tessera.Tessera(cls, uid, *args, **kwargs)

Bases: mosaic.core.base.RemoteBase

A tessera is an actor in the mosaic parallelism model.

A tessera represents an object that is instantiated in a remote portion of the network, and which we reference through a proxy. This proxy allows us to execute methods on that remote object simply by calling the method.

A tessera is kept in memory at the worker for as long as there are proxy references to it. If none exist, it will be made available for garbage collection.

Objects of class Tessera should not be instantiated directly by the user and the @mosaic.tessera decorator should be used instead.

Parameters

• cls (type) – Class of the remote object.

• uid (str) – UID assigned to the tessera.

async call_safe(sender_id, method, task)

Call a method while handling exceptions, which will be sent back to the sender if they arise.

Parameters

• sender_id (str) – UID of the original caller.

• method (callable) – Method to execute.

• task (Task) – Task that has asked for the execution of the method.

property collectable

Whether the object is ready for collection.

get_attr(item)

Access attributes from the underlying object.

Parameters

item (str) – Name of the attribute.

property is_parameter

listen()

Start the listening loop that consumes tasks.

async listen_async()

Listening loop that consumes tasks from the tessera queue.

make_parameter()

Transform the tessera into a parameter and return the object.

Returns

Return type

object

property obj

Internal object.

queue_task(task)

Add a task to the queue of the tessera.

Parameters

task (Task) –

classmethod remote_cls()

Class of the remote.

remote_runtime

Proxies that have references to this tessera.

send_exception(sender_id=None, method=None, task=None)

Context manager that handles exceptions by sending them back to the uid.

Parameters

• sender_id (str) – Remote UID.

• method (callable) – Method being executed.

• task (Task) – Task that has asked for the execution of the method.

set_attr(item, value)

Set attributes on the underlying object.

Parameters

• item (str) – Name of the attribute.

• value (object) –

type = 'tessera'

class mosaic.core.tessera.TesseraProxy(cls, *args, **kwargs)

Bases: mosaic.core.base.ProxyBase

Objects of this class represent connections to remote tessera, allowing us to call methods on them.

Objects of class TesseraProxy should not be instantiated directly by the user and the @mosaic.tessera decorator should be used instead.

Parameters

• cls (type) – Class of the remote object.

• args (tuple, optional) – Arguments for the instantiation of the remote tessera.

• kwargs (optional) – Keyword arguments for the instantiation of the remote tessera.

property collectable

Whether the object is ready for collection.

get_attr(item)

Get at attribute from the remote tessera.

Parameters

item (str) –

Returns

Return type

AwaitableOnly

async init(*args, **kwargs)

Asynchronous correlate of __init__.

property is_parameter

make_parameter(*args, **kwargs)

Transform the proxy into a parameter.

Returns

Return type

object

classmethod remote_cls()

Class of the remote.

remote_runtime

Proxy to the runtime where the tessera lives.

property runtime_id

UID of the runtime where the tessera lives.

async classmethod select_worker(runtime=None)

Select an available worker.

Parameters

runtime (str or Runtime, optional) – If a valid runtime is given, this will be selected as the target worker.

Returns

UID of the target worker.

Return type

str

set_attr(item, value)

Set an attribute on the remote tessera.

Parameters

• item (str) –

• value (object) –

type = 'tessera_proxy'

class mosaic.core.tessera.ArrayProxy(cls, *args, **kwargs)

Bases: mosaic.core.base.CMDBase

Objects of this class represent more a set of remote tesserae that may live on one or more remote runtimes. An array proxy allows us to reference all of them together through a common interface, as well as map calls to them.

Objects of class ArrayProxy should not be instantiated directly by the user and the @mosaic.tessera decorator should be used instead.

Parameters

• cls (type) – Class of the remote object.

• args (tuple, optional) – Arguments for the instantiation of the remote tessera.

• len (int, optional) – Length of the array, defaults to 1.

• kwargs (optional) – Keyword arguments for the instantiation of the remote tessera.

get_attr(item)

Get at attribute from the remote tessera.

Parameters

item (str) –

Returns

Return type

AwaitableOnly

async init(*args, **kwargs)

Asynchronous correlate of __init__.

make_parameter(*args, **kwargs)

Transform the proxy into a parameter.

Returns

Return type

list

remote_runtime

Proxy to the runtime where the tessera lives.

classmethod remote_type()

Type of mosaic object.

property runtime_id

UID of the runtime where the tessera lives.

set_attr(item, value)

Set an attribute on the remote tessera.

Parameters

• item (str) –

• value (object) –

type = 'tessera_proxy_array'

class mosaic.core.tessera.ParameterMixin

Bases: object

A parameter is a Python object that, when moved across different runtimes in the mosaic network, will retain a reference to its original, root object.

This reference means that changes to a local object can be propagated to the root object using obj.method(..., propagate=True).

It also means that attributes of the root object can be changed using obj.set('attr', value). The latest value of an attribute can be pulled from the root object by doing await obj.get('attr').

Objects of class Parameter should not be instantiated directly by the user and the @mosaic.tessera decorator should be used instead.

property cached

async get(item)

property has_tessera

property is_proxy

property is_tessera

async publish()

async pull(attr=None)

async push(attr=None, publish=False)

property ref

set(item, value)