Stream Factories

shtk.StreamFactory subclasses are templates used to define the properties of shtk.Stream instances. shtk.Stream instances are pairs of file-like objects (one for reading data from the process, one for writing data to the process) used for communication with running processes.

shtk.StreamFactory instances are typically constructed via calls to shtk.PipelineNodeFactory.stdin(), shtk.PipelineNodeFactory.stdout(), and shtk.PipelineNodeFactory.stderr().

shtk.StreamFactory

class shtk.StreamFactory

Bases: ABC

Base class for templates creating associated Stream instances

abstract build(job)

Instantiates the Stream instance

Parameters: job (Job) – job to use for current working directory and environment variables.
Returns: The constructed Stream instance.
Return type: Stream

shtk.FileStreamFactory

class shtk.FileStreamFactory(partial_path, mode)

Bases: StreamFactory

Creates a template for FileStream instances

Parameters

partial_path (str or pathlib.Path) – The absolute or job.cwd relative path to the file.
mode (str) – The mode to pass to open() when instantiating the FileStream.

partial_path

The absolute or job.cwd relative path to the file.

Type: pathlib.Path

mode

The mode to pass to open() when instantiating the FileStream.

Type: str

build(job)

Instantiates the FileStream instance

Parameters: job (Job) – job to use for current working directory and environment variables.
Returns: The constructed FileStream instance.
Return type: FileStream

shtk.ManualStreamFactory

class shtk.ManualStreamFactory(fileobj_r=None, fileobj_w=None)

Bases: StreamFactory

Creates a template for ManualStream instances

Parameters

fileobj_r (file-like or None) – A file-like object suitable for reading. None implies os.devnull should be used (Default value = None).
fileobj_w (file-like or None) – A file-like object suitable for writing. None implies os.devnull should be used (Default value = None).

fileobj_r

A file-like object suitable for reading. None implies os.devnull should be used.

Type: file-like or None

fileobj_w

A file-like object suitable for writing. None implies os.devnull should be used.

Type: file-like or None

build(job)

Instantiates the ManualStream instance

Parameters: job (Job) – job to use for current working directory and environment variables.
Returns: The constructed ManualStream instance.
Return type: ManualStream

shtk.NullStreamFactory

class shtk.NullStreamFactory

Bases: StreamFactory

Creates a template for NullStream instances

build(job)

Instantiates the NullStream instance

Parameters: job (Job) – job to use for current working directory and environment variables.
Returns: The constructed NullStream instance.
Return type: NullStream

shtk.PipeStreamFactory

class shtk.PipeStreamFactory(flags=0)

Bases: StreamFactory

Creates a template for PipeStream instances

Parameters: flags (int) – flags to pass to PipeStream constructor (Default value = 0).

flags

flags to pass to PipeStream constructor

Type: int

build(job)

Instantiates the PipeStream instance

Parameters: job (Job) – job to use for current working directory and environment variables.
Returns: The constructed PipeStream instance.
Return type: PipeStream