fpipe 0.0.9

Library for working with file-likes as piped streams

fPipe

python framework for data manipulation and metadata extraction built around the python file-like api.

Disclaimer: framework is currently in Alpha, production use discouraged

Installing

Designed for python 3.7, for S3 support you need boto3

brew install python3
pip3 install fpipe
# Optional
pip3 install boto3

Getting started

Example that reads a stream, calculates some file info, writes file to disk and prints the original stream to stdout

import io

from fpipe.file import FileStream
from fpipe.generators.fileinfo import FileInfoGenerator
from fpipe.generators.local import LocalFileGenerator
from fpipe.meta.path import Path
from fpipe.meta.checksum import MD5CheckSum
from fpipe.meta.size import SizeCalculated

example_streams = (
    FileStream(
        io.BytesIO(
            bytes(f'{name}', encoding='utf-8') * 2 ** 6
        ),
        meta=[Path(f'{name}.file')]
    )
    for name in ('x', 'y', 'z')
)
gen = FileInfoGenerator(example_streams, [SizeCalculated, MD5CheckSum])
for f in LocalFileGenerator(gen, pass_through=True, pathname_resolver=lambda x: x.meta(Path).value):
    print(f"Name: {f.meta(Path)}")
    while True:
        b = f.file.read(2)
        print(b.decode('utf-8'), end='')
        if not b:
            break
    print(f"\nChecksum: {f.meta(MD5CheckSum).value}\n")

See unittests for more examples

Run tests and verify pypi compatibility

To run tests install tox and twine with pip, go to project root and run tox

# python3 -m venv .venv
# Activate virtualenv
source .venv/bin/activate
# Run tests
tox
# Build distribution
python setup.py sdist bdist_wheel
# Validate distribution
twine check dist/*

Rationale

NOTE: wip

Unix pipes or chained python generators are ideal when the pipeline does not split and does not require metadata from previous steps.

Working around these challenges may lead to unnecessary complication and caching.

This framework's main intentions are to provide general solutions to the aforementioned challenges through a minimalistic and intuitive API.

Design

NOTE: wip

The whole framework is built around 2 main concepts:

• class File
  • Base class for files
• class FileGenerator
  • Initialized with an iterable of Files and yields a different File

Files have 3 different type:

• class FilePointer(File): A pointer to a file that could be used to produce a FileStream
• class FileStream(File): File that produces a data stream
• class FileSeekableStream(FileStream) File that produces a seekable stream

In addition we have class FileMeta which provides meta-data often needed by FileGenerators to be able to generate files.

Built With

• travis
• tox

Contributing

Bug-reports and pull requests on github

Versioning

Any version change could break the public API (until 1.0.0 release)

Pypi

Github

License

This project is licensed under the MIT License - see the LICENSE.txt file for details