#164 Use type hints to build your next CLI app

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By Michael Kennedy and Brian Okken. Discovered by Player FM and our community — copyright is owned by the publisher, not Player FM, and audio is streamed directly from their servers. Hit the Subscribe button to track updates in Player FM, or paste the feed URL into other podcast apps.

Sponsored by Datadog: pythonbytes.fm/datadog

Michael #1: Data driven journalism via cjworkbench

  • via Michael Paholski
  • The data journalism platform with built in training
  • Think spreadsheet + ETL automation
  • Designed around modular tools for data processing -- table in, table out -- with no code required
  • Features include:
    • Modules to scrape, clean, analyze and visualize data
    • An integrated data journalism training program
    • Connect to Google Drive, Twitter, and API endpoints.
    • Every action is recorded, so all workflows are repeatable and transparent
    • All data is live and versioned, and you can monitor for changes.
    • Write custom modules in Python and add them to the module library

Brian #2: remi: A Platform-independent Python GUI library for your applications.

  • Python REMote Interface library.
  • “Remi is a GUI library for Python applications which transpiles an application's interface into HTML to be rendered in a web browser. This removes platform-specific dependencies and lets you easily develop cross-platform applications in Python!”
  • No dependencies. pip install git+https://github.com/dddomodossola/remi.git doesn’t install anything else.
  • Yes. Another GUI in a web page, but for quick and dirty internal tools, this will be very usable.
  • Basic app:
 import remi.gui as gui from remi import start, App class MyApp(App): def __init__(self, *args): super(MyApp, self).__init__(*args) def main(self): container = gui.VBox(width=120, height=100) self.lbl = gui.Label('Hello world!') self.bt = gui.Button('Press me!') self.bt.onclick.do(self.on_button_pressed) container.append(self.lbl) container.append(self.bt) return container def on_button_pressed(self, widget): self.lbl.set_text('Button pressed!') self.bt.set_text('Hi!') start(MyApp) 

Michael #3: Typer

  • Build great CLIs. Easy to code.
  • Based on Python type hints.
  • Typer is FastAPI's little sibling. And it's intended to be the FastAPI of CLIs.
  • Just declare once the types of parameters (arguments and options) as function parameters.
  • You do that with standard modern Python types.
  • You don't have to learn a new syntax, the methods or classes of a specific library, etc.
  • Based on Click
  • Example (min version)
 import typer def main(name: str): typer.echo(f"Hello {name}") if __name__ == "__main__": typer.run(main) 

Brian #4: Effectively using Matplotlib

  • Chris Moffitt
  • “… I think I was a little premature in dismissing matplotlib. To be honest, I did not quite understand it and how to use it effectively in my workflow.”
  • That very much sums up my relationship with matplotlib. But I’m ready to take another serious look at it.
  • one reason for complexity is 2 interfaces
    • MATLAB like state-based interface
    • object based interface (use this)
  • recommendations:
    • Learn the basic matplotlib terminology, specifically what is a Figure and an Axes .
    • Always use the object-oriented interface. Get in the habit of using it from the start of your analysis.
    • Start your visualizations with basic pandas plotting.
    • Use seaborn for the more complex statistical visualizations.
    • Use matplotlib to customize the pandas or seaborn visualization.
  • Runs through an example
  • Describes figures and plots
  • Includes a handy reference for customizing a plot.
  • Related: StackOverflow answer that shows how to generate and embed a matplotlib image into a flask app without saving it to a file.
  • Style it with pylustrator.readthedocs.io :)

Michael #5: Django Simple Task

  • django-simple-task runs background tasks in Django 3 without requiring other services and workers.
  • It runs them in the same event loop as your ASGI application.
  • Here’s a simple overview of how it works:
    1. On application start, a queue is created and a number of workers starts to listen to the queue
    2. When defer is called, a task(function or coroutine function) is added to the queue
    3. When a worker gets a task, it runs it or delegates it to a threadpool
    4. On application shutdown, it waits for tasks to finish before exiting ASGI server
  • It is required to run Django with ASGI server.
  • Example
 from django_simple_task import defer def task1(): time.sleep(1) print("task1 done") async def task2(): await asyncio.sleep(1) print("task2 done") def view(requests): defer(task1) defer(task2) return HttpResponse(b"My View") 

Brian #6: PyPI Stats at pypistats.org

  • Simple interface. Pop in a package name and get the download stats.
  • Example use: Why is my open source project now getting PRs and issues?
  • I’ve got a few packages on PyPI, not updated much.
    • cards and submark are mostly for demo purposes for teaching testing.
    • pytest-check is a pytest plugin that allows multiple failures per test.
  • I only hear about issues and PRs on one of these. So let’s look at traffic.
    • cards: downloads day: 2 week: 24 month: 339
    • submark: day: 5 week: 9 month: 61
    • pytest-check: day: 976 week: 4,524 month: 19,636
  • That totally explains why I need to start actually supporting pytest-check. Cool.
  • Note: it’s still small.

Extras:

  • Comment from January Python PDX West meetup
    • “Please remember to have one beginner friendly talk per meetup.”
    • Good point.
    • Even if you can’t present here in Portland / Hillsboro, or don’t want to, I’d love to hear feedback of good beginner friendly topics that are good for meetups.
  • PyCascades 2020

    • discount code listeners-at-pycascades for 10% off
  • FireFox 72 is out with anti-fingerprinting and PIP - Ars Technica

Joke:

Language essays comic

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