selinon.system module

Core Selinon logic for system representation, parsing and handling actions.

class selinon.system.System(tasks=None, flows=None, storages=None, task_classes=None)[source]

Bases: object

The representation of the whole system.

add_flow(flow)[source]

Register a flow in the system.

Parameters:flow (flow) – a flow to be registered
add_storage(storage)[source]

Add storage to system.

Parameters:storage – storage that should be added
add_task(task)[source]

Register a task in the system.

Parameters:task (selinon.selinon_task.Task) – a task to be registered
class_of_task(task)[source]

Return task class of a task.

Parameters:task – task to look task class for
Returns:TaskClass or None if a task class for task is not available
dispatcher_queue_names()[source]

Get information about queue names per dispatcher/flow.

Returns:dispatcher queue names based on flow names
dump2file(output_file)[source]

Perform system dump to a Python source code.

Parameters:output_file – an output file to write to
dump2stream(stream)[source]

Perform system dump to a Python source code to an output stream.

Parameters:stream – an output stream to write to
flow_by_name(name, graceful=False)[source]

Find a flow by its name.

Parameters:
  • name – a flow name
  • graceful – if True, no exception is raised if flow couldn’t be found
Returns:

flow with name ‘name’
Return type:

Flow
Raises:

ConfigurationError – on non-existing flow name
classmethod from_dict(nodes_definition, flow_definitions, no_check=False)[source]

Construct System from dictionaries.

Parameters:
  • nodes_definition (list) – parsed nodes definition
  • flow_definitions – a list of parsed flow definitions
  • no_check – True if system shouldn’t be checked for consistency (recommended to check)
Returns:

System instance
Return type:

System
classmethod from_files(nodes_definition_file, flow_definition_files, no_check=False)[source]

Construct System from files.

Parameters:
  • nodes_definition_file (str) – path to nodes definition file
  • flow_definition_files (str) – path to files that describe flows
  • no_check – True if system shouldn’t be checked for consistency (recommended to check)
Returns:

System instance
Return type:

System
node_by_name(name, graceful=False)[source]

Find a node (flow or task) by its name.

Parameters:
  • name – a node name
  • graceful – if True, no exception is raised if node couldn’t be found
Returns:

flow with name ‘name’
Return type:

Node
Raises:

KeyError
plot_graph(output_dir, image_format=None)[source]

Plot system flows to graphs - each flow in a separate file.

Parameters:
  • output_dir – output directory to write graphs of flows to
  • image_format – image format, the default is svg if None
Returns:

list of file names to which the graph was rendered
Return type:

List[str]
storage_by_name(name, graceful=False)[source]

Retrieve storage by its name.

Parameters:
  • name – name of the storage
  • graceful – if true, exception is raised if no such storage with name name is found
Returns:

storage
task_by_name(name, graceful=False)[source]

Find a task by its name.

Parameters:
  • name – a task name
  • graceful – if True, no exception is raised if task couldn’t be found
Returns:

task with name ‘name’
Return type:

selinon.selinon_task.Task
Raises:

ConfigurationError – on non-existing task name
task_queue_names()[source]

Get information about queue names per task.

Returns:corresponding mapping from task name to task queue