`aiomas.rpc`¶

This module implements remote procedure calls (RPC) on top of request-reply channels (see aiomas.channel).

RPC connections are represented by instances of RpcClient (one for each side of a aiomas.channel.Channel). They provide access to the functions served by the remote side of the channel via Proxy instances. Optionally, they can provide their own RPC service (via rpc_service()) so that the remote side can make calls as well.

An RPC service is defined by a Router. A router resolves paths requested by the remote side. It can also handle sub-routers (which allows you to build hierarchies for nested calls) and is able to perform a reverse-lookup of a router (mapping a fuction to its path).

Routers provide the functions and methods of dictionaries or class instances. Dict routers can be created by passing a dictionary to Router. For classes, you create a Service instance as rpc class attribute. This creates a Descriptor which then creates a new router instance for each class instance.

Functions that should be callable from the remote side must be decorated with expose(); Router.expose() and Service.expose() are aliases for it.

aiomas.rpc.open_connection(addr, *, router=None, add_to=None, **kwds)[source]¶

Return an RpcClient connected to addr.

This is a convenience wrapper for aiomas.channel.open_connection(). All keyword arguments (kwds) are forwared to it.

You can optionally pass a router to allow the remote site to call back to us.

If you want to cleanly cancel all rpc_service() tasks created for each connection made to router, you can pass a set via add_to. All tasks will then be append to it.

aiomas.rpc.start_server(addr, router, add_to=None, **kwds)[source]¶

Start a server socket on host:port and create an RPC service with the provided handler for each new client.

This is a convenience wrapper for aiomas.channel.start_server(). All keyword arguments (kwds) are forwared to it.

router must be a Router instance for the rpc_service() that is started for each new connection.

If you want to cleanly cancel all rpc_service() tasks created for each connection made to router, you can pass a set via add_to. All tasks will then be append to it.

Raise a ValueError if handler is not decorated properly.

aiomas.rpc.rpc_service(router, channel)[source]¶

Serve the functions provided by the Router router via the Channel channel.

Forward errors raised by the handler to the caller.

Stop running when the connection closes.

aiomas.rpc.expose(func)[source]¶

Decorator that enables RPC access to the decorated function.

func will not be wrapped but only gain an __rpc__ attribute.

class aiomas.rpc.DictWrapper(router, dict)[source]¶: Wrapper for dicts so that they can be used as RPC routers.

class aiomas.rpc.Router(obj)[source]¶

The Router resolves paths to functions provided by their object obj (or its children). It can also perform a reverse lookup to get the path of the router (and the router’s obj).

The obj can be a class, an instance or a dict.

obj = None¶: The object to which this router belongs to.

name = None¶: The name of the router (empty for root routers).

parent = None¶: The parent router or None for root routers.

path¶: The path to this router (without trailing slash).

resolve(path)[source]¶

Resolve path and return the corresponding function.

path is a string with path components separated by / (without trailing slash).

Raise a LookupError if no handler function can be found for path or if the function is not exposed (see expose()).

static expose(func)¶: Alias for expose().

add(name)[source]¶

Add the sub-router name (stored at self.obj.<name>) to this router.

Convenience wrapper for set_sub_router().

set_sub_router(router, name)[source]¶: Set self as parent for the router named name.

class aiomas.rpc.Service(sub_routers=())[source]¶

A Data Descriptor that creates a new Router instance for each class instance to which it is set.

The attribute name for the Service should always be rpc:

class Spam:
    rpc = aiomas.rpc.Service()

You can optionally pass a list with the attribute names of classes with sub-routers. This required to build hierarchies of routers, e.g.:

class Eggs:
    rpc = aiomas.rpc.Service()


class Spam:
    rpc = aiomas.rpc.Service(['eggs'])

    def __init__(self):
        self.eggs = Eggs()  # Instance with a sub-router

static expose(func)¶: Alias for expose().

class aiomas.rpc.RpcClient(channel, router=None, add_to=None)[source]¶

The RpcClient provides proxy objects for remote calls via its remote attribute.

channel is a Channel instance for communicating with the remote side.

If router is not None, it will also start its own RPC service so the other side can make calls to us as well.

If you want to cleanly cancel all rpc_service() tasks created for each connection made to router, you can pass a set via add_to. All tasks will then be append to it.

remote¶: A Proxy for remote methods.

close()[source]¶: Close the connection.

class aiomas.rpc.Proxy(channel, path)[source]¶

Proxy object for remote objects and functions.

__getattr__(name)[source]¶: Return a new proxy for name.

__call__(*args, **kwargs)[source]¶

Call the remote method represented by this proxy and return its result.

The result is a future, so you need to yield from it in order to get the actual return value (or exception).

aiomas.rpc¶

`aiomas.rpc`¶