rsb.patterns¶

Contains communication pattern implementations.

For instance, RPC based on the basic participants rsb.Listener and rsb.Informer.

Code author: jmoringe

Code author: jwienke

Classes

`LocalMethod`(scope, config, server, name, …)	Implements and makes available a method of a local server.
`LocalServer`(scope, config)	Provide local methods to remote clients.
`Method`(scope, config, server, name, …)	Base class for methods of local or remote servers.
`Reader`(scope, config[, queue_size])	Provides a pull model for fetching received events.
`RemoteMethod`(scope, config, server, name, …)	Represents a method provided by a remote server.
`RemoteServer`(scope, config)	Represents remote servers in a way that allows using normal methods calls.
`Server`(scope, config)	Base class for local or remote servers.

Exceptions

RemoteCallError(scope, method, error)

Represents an error when calling a remote method implementation.

exception rsb.patterns.RemoteCallError(scope, method, error)¶

Bases: RuntimeError

Represents an error when calling a remote method implementation.

Code author: jmoringe

with_traceback()¶: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

args¶

property method¶

property scope¶

class rsb.patterns.LocalMethod(scope, config, server, name, func, request_type, reply_type, allow_parallel_execution)¶

Bases: rsb.patterns.Method

Implements and makes available a method of a local server.

The actual behavior of methods is implemented by invoking arbitrary user-supplied callables.

Code author: jmoringe

activate()¶

deactivate()¶

Deactivate a participant by tearing down all connection logic.

This needs to be called in case you want to ensure that programs can terminate correctly.

classmethod get_connectors(direction, config)¶

make_informer()¶

make_listener()¶

property config¶

property informer¶

property listener¶

property name¶

property participant_id¶

property reply_type¶

property request_type¶

property scope¶

property server¶

property transport_urls¶

Return of list transport URLs for all used transports.

Returns: Set of transport URLs.
Rtype: set

class rsb.patterns.LocalServer(scope, config)¶

Bases: rsb.patterns.Server

Provide local methods to remote clients.

Objects of this class associate a collection of method objects which are implemented by callback functions with a scope under which these methods are exposed for remote clients.

Code author: jmoringe

Create a LocalServer that provides methods under a given scope.

Parameters

scope – The scope under which the methods of the newly created server should be provided.
config – The transport configuration that should be used for communication performed by this server.

Type scope

rsb.Scope

Type config

rsb.ParticipantConfig

See also

rsb.create_local_server

activate()¶

add_method(name, func, request_type=<class 'object'>, reply_type=<class 'object'>, allow_parallel_execution=False)¶

Add a method named name that is implemented by func.

Parameters

name – The name of of the new method.
func – A callable object or a single argument that implements the desired behavior of the new method.
request_type – A type object indicating the type of request data passed to the method.
reply_type – A type object indicating the type of reply data of the method.
allow_parallel_execution – if set to True, the method will be called fully asynchronously and even multiple calls may enter the method in parallel. Also, no ordering is guaranteed anymore.

Type name

str

Type request_type

types.TypeType

Type allow_parallel_execution

bool

Returns

The newly created method.

Rtype

LocalMethod

deactivate()¶

Deactivate a participant by tearing down all connection logic.

This needs to be called in case you want to ensure that programs can terminate correctly.

classmethod get_connectors(direction, config)¶

get_method(name)¶

remove_method(method)¶

property config¶

property methods¶

property participant_id¶

property scope¶

property transport_urls¶

Return of list transport URLs for all used transports.

Returns: Set of transport URLs.
Rtype: set

class rsb.patterns.Method(scope, config, server, name, request_type, reply_type)¶

Bases: rsb.Participant

Base class for methods of local or remote servers.

Objects of this class are methods which are associated to a local or remote server. Within a server, each method has a unique name.

This class is primarily intended as a superclass for local and remote method classes.

Code author: jmoringe

Create a new Method object for the given name and server.

Parameters

server – The remote or local server to which the method is associated.
name – The name of the method. Unique within a server.
request_type – The type of the request argument accepted by the method.
reply_type – The type of the replies produced by the method.

Type name

str

Type request_type

types.TypeType

Type reply_type

types.TypeType

activate()¶

deactivate()¶

Deactivate a participant by tearing down all connection logic.

This needs to be called in case you want to ensure that programs can terminate correctly.

classmethod get_connectors(direction, config)¶

property config¶

property informer¶

property listener¶

property name¶

property participant_id¶

property reply_type¶

property request_type¶

property scope¶

property server¶

property transport_urls¶

Return of list transport URLs for all used transports.

Returns: Set of transport URLs.
Rtype: set

class rsb.patterns.Reader(scope, config, queue_size=-1)¶

Bases: rsb.Participant

Provides a pull model for fetching received events.

Clients need to continuously call the read() method to fetch events. Internally, events are buffered in a queue until they are picked up by clients.

Code author: jwienke

Create a new Reader for scope.

Parameters

scope – The scope of the channel in which the new reader should participate.
config – The configuration that should be used by this Reader.
queue_size – Size of the internal queue of events that are held by the reader. If read isn’t called fast enough the underlying transport will be blocked. Negative numbers create an infinite queue.

Type scope

Scope or accepted by Scope constructor

Type config

ParticipantConfig

Type queue_size

int

See also

rsb.create_reader()

activate()¶

deactivate()¶

Deactivate a participant by tearing down all connection logic.

This needs to be called in case you want to ensure that programs can terminate correctly.

classmethod get_connectors(direction, config)¶

read(block=True)¶

Read the next event from the wire.

Optionally blocks until an event is available.

Parameters

block – If True, block until the next event is received.

Type block

bool

Returns

rsb.Event: the received event

property config¶

property participant_id¶

property scope¶

property transport_urls¶

Return of list transport URLs for all used transports.

Returns: Set of transport URLs.
Rtype: set

class rsb.patterns.RemoteMethod(scope, config, server, name, request_type, reply_type)¶

Bases: rsb.patterns.Method

Represents a method provided by a remote server.

Method objects are callable like regular bound method objects.

Code author: jmoringe

activate()¶

asynchronous(arg=None)¶

Call the method asynchronously and returns a Future.

Calls the represented method with argument arg, returning a Future instance that can be used to retrieve the result.

If arg is an instance of Event, the result of the method call is an Event containing the object returned by the remote method as payload. If arg is of any other type, the result is the payload of the method call is the object that was returned by the remote method.

The call to this method returns immediately, even if the remote method did produce a result yet. The returned Future instance has to be used to retrieve the result.

Parameters: arg – The argument object that should be passed to the remote method. A converter has to be available for the type of arg.
Returns: A Future or DataFuture instance that can be used to check the success of the method call, wait for the result and retrieve the result.
Rtype: Future or DataFuture
Raises RemoteCallError: If an error occurs before the remote was invoked.

See also

__call__

Examples

>>> my_server.echo.asynchronous('bla')
<Future running at 3054cd0>
>>> my_server.echo.asynchronous('bla').get()
'bla'
>>> my_server.echo.asynchronous(Event(scope=my_server.scope,
...                           data='bla', type=str)).get()
Event[id = ..., data = 'bla', ...]

deactivate()¶

Deactivate a participant by tearing down all connection logic.

This needs to be called in case you want to ensure that programs can terminate correctly.

classmethod get_connectors(direction, config)¶

make_informer()¶

make_listener()¶

property config¶

property informer¶

property listener¶

property name¶

property participant_id¶

property reply_type¶

property request_type¶

property scope¶

property server¶

property transport_urls¶

Return of list transport URLs for all used transports.

Returns: Set of transport URLs.
Rtype: set

class rsb.patterns.RemoteServer(scope, config)¶

Bases: rsb.patterns.Server

Represents remote servers in a way that allows using normal methods calls.

Code author: jmoringe

Create a new RemoteServer providing methods on the given scope.

Parameters

scope – The common super-scope under which the methods of the remote created server are provided.
config – The configuration that should be used by this server.

Type scope

rsb.Scope

Type config

rsb.ParticipantConfig

See also

rsb.create_remote_server

activate()¶

add_method(method)¶

deactivate()¶

Deactivate a participant by tearing down all connection logic.

This needs to be called in case you want to ensure that programs can terminate correctly.

ensure_method(name)¶

classmethod get_connectors(direction, config)¶

get_method(name)¶

remove_method(method)¶

property config¶

property methods¶

property participant_id¶

property scope¶

property transport_urls¶

Return of list transport URLs for all used transports.

Returns: Set of transport URLs.
Rtype: set

class rsb.patterns.Server(scope, config)¶

Bases: rsb.Participant

Base class for local or remote servers.

Objects of this class represent local or remote serves. A server is basically a collection of named methods that are bound to a specific scope.

This class is primarily intended as a superclass for local and remote server classes.

Code author: jmoringe

Create a Server that provides methods under the given scope.

Parameters

scope – The scope under which methods of the server are provided.
config – The transport configuration that should be used for communication performed by this server.

Type scope

rsb.Scope

Type config

rsb.ParticipantConfig

activate()¶

add_method(method)¶

deactivate()¶

Deactivate a participant by tearing down all connection logic.

This needs to be called in case you want to ensure that programs can terminate correctly.

classmethod get_connectors(direction, config)¶

get_method(name)¶

remove_method(method)¶

property config¶

property methods¶

property participant_id¶

property scope¶

property transport_urls¶

Return of list transport URLs for all used transports.

Returns: Set of transport URLs.
Rtype: set