puffy 0.1.2

A collection of modules with zero-dependencies to help manage common programming tasks.

PUFFY

A collection of modules with zero-dependencies to help manage common programming tasks.

pip install puffy

Usage examples:

from puffy.error import catch_errors, StackedException

# This function will never fail. Instead, the error is safely caught.
@catch_errors
def fail():
    raise Exception("Failed")
    return "yes"

err, resp = fail() # `err` and `resp` are respectively None and Object when the function is successull. Otherwise, they are respectively StackedException and None.

from puffy.object import JSON as js

obj = js({ 'hello':'world' })
obj['person']['name'] = 'Nic' # Notice it does not fail.
obj.s('address.line1', 'Magic street') # Sets obj.address.line1 to 'Magic street' and return 'Magic street'

Table of contents

• APIs
  • error
    • Basic error APIs
    • Nested errors and error stack
  • object
    • JSON API
• Dev
  • CLI commands
  • Install dependencies with easypipinstall
  • Linting, formatting and testing
    • Ignoring flake8 errors
    • Skipping tests
    • Executing a specific test only
  • Building and distributing this package
• FAQ
• References
• License

APIs

error

The error module exposes the following APIs:

• catch_errors: A higher-order function that returns a function that always return a tuple (error, response). If the error is None, then the function did not fail. Otherwise, it did and the error object can be used to build an error stack.
• StackedException: A class that inherits from Exception. Use it to stack errors.

Basic error APIs

from puffy.error import catch_errors, StackedException

# This function will never fail. Instead, the error is safely caught.
@catch_errors
def fail():
    raise Exception("Failed")
    return "yes"

err, resp = fail() 

print(resp) # None
print(type(err)) # <class 'src.puffy.error.StackedException'> which inherits from Exception
print(str(err)) # Failed
print(len(err.stack)) # 1
print(str(err.stack[0])) # Failed
print(err.stack[0].__traceback__) # <traceback object at 0x7fc69066bf00>

# Use the `strinfigy` method to extract the full error stack details.
print(err.strinfigy()) 
# error: Failed
#   File "blablabla.py", line 72, in safe_exec
#     data = ffn(*args, **named_args)
#   File "blablabla.py", line 28, in fail
#     raise Exception("Failed")

Nested errors and error stack

from puffy.error import catch_errors, StackedException

# This function will never fail. Instead, the error is safely caught.
@catch_errors("Should fail")
def fail():
    err, resp = fail_again()
    if err:
        raise StackedException("As expected, it failed!", err) 
        # StackedException accepts an arbitrary number of inputs of type str or Exception:
        # 	- raise StackedException(err) 
        # 	- raise StackedException('This', 'is', 'a new error') 
    return "yes"

@catch_errors("Should fail again")
def fail_again():
    raise Exception("Failed again")
    return "yes"

err, resp = fail()

print(len(err.stack)) # 4
print(str(err.stack[0])) # Should fail
print(str(err.stack[1])) # As expected, it failed!
print(str(err.stack[2])) # Should fail again
print(str(err.stack[3])) # Failed again

# Use the `strinfigy` method to extract the full error stack details.
print(err.strinfigy()) 
# error: Should fail
#   File "blablabla.py", line 72, in fail
# error: As expected, it failed!
#   File "blablabla.py", line 72, in fail
# error: Should fail again
#   File "blablabla.py", line 72, in fail
# error: Failed again
#   File "blablabla.py", line 72, in safe_exec
#     data = ffn(*args, **named_args)
#   File "blablabla.py", line 28, in fail_again
#     raise Exception("Failed")

object

JSON API

from puffy.object import JSON as js

obj = js({ 'hello':'world' })
obj['person']['name'] = 'Nic' # Notice it does not fail.
obj.s('address.line1', 'Magic street') # Sets obj.address.line1 to 'Magic street' and return 'Magic street'

print(obj['person']['name']) # Nic
print(obj) # { 'hello':'world', 'person': { 'name': 'Nic' } }
print(obj.g('address.line1')) # Magic street
print(obj) # { 'hello':'world', 'person': { 'name': None }, 'address': { 'line1': 'Magic street' } }
print(obj.g('address.line2')) # Nonce
print(obj) # { 'hello':'world', 'person': { 'name': None }, 'address': { 'line1': 'Magic street', line2: None } }

Dev

CLI commands

make commands:

Command	Description
make b	Builds the package.
make p	Publish the package to https://pypi.org.
make bp	Builds the package and then publish it to https://pypi.org.
make bi	Builds the package and install it locally (pip install -e .).
make install	Install the dependencies defined in the requirements.txt. This file contains all the dependencies (i.e., both prod and dev).
make install-prod	Install the dependencies defined in the prod-requirements.txt. This file only contains the production dependencies.
make n	Starts a Jupyter notebook for this project.
make t	Formats adnd then lints the project.
easyi numpy	Instals numpy and update setup.cfg, prod-requirements.txt and requirements.txt.
easyi flake8 -D	Instals flake8 and update setup.cfg and requirements.txt.
easyu numpy	Uninstals numpy and update setup.cfg, prod-requirements.txt and requirements.txt.

Install dependencies with easypipinstall

easypipinstall adds two new CLI utilities: easyi (install) and easyu (uninstall).

Examples:

easyi numpy

This installs numpy (via pip install) then automatically updates the following files:

• setup.cfg (WARNING: this file must already exists):

   [options]
   install_requires = 
   	numpy
  

• requirements.txt and prod-requirements.txt

easyi flake8 black -D

This installs flake8 and black (via pip install) then automatically updates the following files:

• setup.cfg (WARNING: this file must already exists):

   [options.extras_require]
   dev = 
   	black
   	flake8
  

• requirements.txt only, as those dependencies are installed for development purposes only.

easyu flake8

This uninstalls flake8 as well as all its dependencies. Those dependencies are uninstalled only if they are not used by other project dependencies. The setup.cfg and requirements.txt are automatically updated accordingly.

Linting, formatting and testing

make t

This command runs the following three python executables:

black ./
flake8 ./
pytest --capture=no --verbose $(testpath)

• black formats all the .py files, while flake8 lints them.
• black is configured in the pyproject.toml file under the [tool.black] section.
• flake8 is configured in the setup.cfg file under the [flake8] section.
• pytest runs all the .py files located under the tests folder. The meaning of each option is as follow:
  • --capture=no allows the print function to send outputs to the terminal.
  • --verbose displays each test. Without it, the terminal would only display the count of how many passed and failed.
  • $(testpath) references the testpath variable. This variable is set to tests (i.e., the tests folder) by default. This allows to override this default variable with something else (e.g., a specific test to only run that one).

Ignoring flake8 errors

This project is pre-configured to ignore certain flake8 errors. To add or remove flake8 errors, update the extend-ignore property under the [flake8] section in the setup.cfg file.

Skipping tests

In your test file, add the @pytest.mark.skip() decorator. For example:

import pytest

@pytest.mark.skip()
def test_self_describing_another_test_name():
	# ... your test here

Executing a specific test only

One of the output of the make t command is list of all the test that were run (PASSED and FAILED). For example:

tests/error/test_catch_errors.py::test_catch_errors_basic PASSED
tests/error/test_catch_errors.py::test_catch_errors_wrapped PASSED
tests/error/test_catch_errors.py::test_catch_errors_nested_errors PASSED
tests/error/test_catch_errors.py::test_catch_errors_StackedException_arbitrary_inputs FAILED

To execute a specific test only, add the testpath option with the test path. For example, to execute the only FAILED test in the example above, run this command:

make t testpath=tests/error/test_catch_errors.py::test_catch_errors_StackedException_arbitrary_inputs

Building and distributing this package

Tl;dr, make bp builds and publishes your package to https://pypi.org.

To build your package, run:

make b

This command is a wrapper around python3 -m build.

To build and publish your package to https://pypi.org, run:

make p

This command is a wrapper around the following commands:

python3 -m build; \
twine upload dist/*

Those two steps have been bundled in a single command:

make bp

To test your package locally before deploying it to https://pypi.org, you can run build and install it locally with this command:

make bi

This command buils the package and follows with pip install -e ..

FAQ

References

License

BSD 3-Clause License

Copyright (c) 2019-2023, Cloudless Consulting Pty Ltd
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this
   list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

3. Neither the name of the copyright holder nor the names of its
   contributors may be used to endorse or promote products derived from
   this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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