Developer Experience

# Developer Experience

## building tools for developers

---

# About Me

* 10+ years of professional experience
* developer, architect, team leader, product owner
* C/C++, FoxPro, Python, Java, Groovy for production
* Python, Go, Erlang, Nimrod for fun
* pragmatic programmer, continuous delivery practitioner
* I like programming, but hate writing code

---

# What Makes A Good Developer Tool?

* Build apps better, faster, stronger.
  * https://github.com/showcases/software-development-tools
* Build software faster with fewer headaches.
  * https://github.com/showcases/productivity-tools
* These tools help you manage servers and deploy happier and more often with more confidence.
  * https://github.com/showcases/devops-tools

---

# command-line tool that helps you

* git
* pip
* make
* grep

---

# starts with install & usage

![UglifyJS installation](uglifyjs_install.png)

![UglifyJS usage](uglifyjs_usage.png)

---

# configurable

* ~/.pypirc, ~/.gitconfig, tox.ini
* .travis.yaml, playbook.yaml
* package.json, Gruntfile
* settings.xml

---

# How to Build One

## with Python

---

# HackerNews CLI

* list **strories**
  * **sort_by** - `newest` or `best`
  * **limit** - number of top stories to show
* **go** to the linked story
* print **comments** for story
* **comment** story on [HackerNews](https://news.ycombinator.com/)

---

# Usage

```bash
$ hn
Usage: hn [OPTIONS] COMMAND [ARGS]...

HackerNews CLI - for hackers

Options:
  --version  Show the version and exit.
  --help     Show this message and exit.

Commands:
  comment   comment story on HackerNews
  comments  show comments for the story
  go        go to the story on HackerNews
  stories   list stories
```

---

# Click

## creating beautiful command line interfaces

* arbitrary nesting of commands
* automatically generates nicely formatted help pages
* parameter types with different behavior
* test functionality CLIs and check their behavior
* batteries included

---

# Group of commands

```python
import click

@click.group()
def hncli():
    """ HackerNews CLI - for hackers """
    pass
```

```python
@hncli.command()
def stories()
    """ list stories """
    pass
```

```python
@hncli.command()
def go()
    """ go to the story on HackerNews """
    pass
```

```python
if __name__ == '__main__':
    hncli()
```

---

# Listing Stories

```python
@cli.command()
@click.option('--sort_by', '-s', default='newest',
              type=click.Choice(['newest', 'best']), help='sort type')
@click.option('--limit', '-l', default=10, type=click.INT,
              help='number of top stories to show')
def stories(sort_by, limit):
    """ list stories """
    pass
```

## usage

```bash
$ hn stories --help
Usage: hn stories [OPTIONS]

list stories

Options:
  -s, --sort_by [newest|best]  sort type
  -l, --limit INTEGER          number of top stories to show
  --help                       Show this message and exit.
```

---

# hn stories example

```bash
$ hn stories
      when      | comments |   id    | title
 6 minutes ago  |    0     | 8616607 | Ask HN: How should I use mTurk to advertise my product?
 7 minutes ago  |    0     | 8616600 | Ask HN: Can You Recommend an Online Mentoring Service?
 8 minutes ago  |    0     | 8616597 | Cornell's robot chef learns, cooks to your taste preferences
 8 minutes ago  |    1     | 8616595 | Show HN: tl;dr{Code} Project from HackRPI hackathon
 15 minutes ago |    0     | 8616580 | US State Department shuts down email due to hackers
 27 minutes ago |    0     | 8616550 | Smile, You’re Speaking Emoji: The rapid evolution of a wordless tongue
 30 minutes ago |    0     | 8616541 | Payment Systems Adventures – Part II
 33 minutes ago |    0     | 8616537 | A Case for Spreadsheets
 40 minutes ago |    0     | 8616513 | Learning AngularJS: How to make an API call using factories
 41 minutes ago |    0     | 8616510 | Journalists + EBay Billionaire = Chaos
```

## with options ...

```bash
$ hn stories --sort_by best --limit 2
      when      | comments |   id    | title
   4 days ago   |    890   | 8595905 | Microsoft takes .NET open source and cross-platform
   3 days ago   |    558   | 8600716 | Letter to Amazon Board from Fired Ad Exec
```

---

# automatic validation

```bash
$ hn stories --limit aa
Usage: hn stories [OPTIONS]

Error: Invalid value for "--limit" / "-l": aa is not a valid integer
```

```bash
$ hn stories -l 3 -s fame
Usage: hn stories [OPTIONS]

Error: Invalid value for "--sort_by" / "-s": invalid choice: fame.
(choose from newest, best)
```

---

# Printing comments

```python
@cli.command()
@click.argument('story_id', type=click.INT, required=True)
def comments(story_id):
    """ show comments for the story """
    comments = Story.fromid(story_id).get_comments()

if not comments:
        echo(style('no coments for story found!', fg='red'))

for comment in comments:
        echo(style(comment.time_ago.center(15), fg='magenta'), nl=False)
        echo('by ' + style(str(comment.user), fg='cyan'))
        echo(comment.body)
```

```bash
$ hn comments --help
Usage: hn comments [OPTIONS] STORY_ID

show comments for the story

Options:
  --help  Show this message and exit.
```

---

# Entry Points FTW!
## instead of using Unix shebangs

* works with Windows
* virtualenv support
* CLI as API

## configure ``setup.py``

```python
setup(
    entry_points={
        'console_scripts': [
            'hn = hncli.cli:cli',
        ],
    },
```

---

# More Power with Click

* parameter types
  * [click.File](http://click.pocoo.org/3/api/#click.File),
    [click.Path](http://click.pocoo.org/3/api/#click.Path)
  * [custom types](http://click.pocoo.org/3/parameters/#implementing-custom-types)
* [input propmts](http://click.pocoo.org/3/prompts/#input-prompts),
  [password prompts](http://click.pocoo.org/3/options/#password-prompts)
* [values from environment variables](http://click.pocoo.org/3/options/#values-from-environment-variables)
* multi commands
  * [from plugins](http://click.pocoo.org/3/commands/#custom-multi-commands)
  * [chaining](http://click.pocoo.org/3/commands/#multi-command-chaining),
    [pipelines](http://click.pocoo.org/3/commands/#multi-command-pipelines)

---

# ... and even more

* [testing](http://click.pocoo.org/3/testing/#testing-click-applications) with
  [file system isolation](http://click.pocoo.org/3/testing/#file-system-isolation) and
  [prompts](http://click.pocoo.org/3/testing/#input-streams)
* [printing to stdout](http://click.pocoo.org/3/utils/#printing-to-stdout) with
  [ANSI colors](http://click.pocoo.org/3/utils/#ansi-colors) and
  [pager support](http://click.pocoo.org/3/utils/#pager-support)
* launching [editors](http://click.pocoo.org/3/utils/#launching-editors) and
  [applications](http://click.pocoo.org/3/utils/#launching-applications)
* showing [progress bars](http://click.pocoo.org/3/utils/#showing-progress-bars)
* support for [Bash completion](http://click.pocoo.org/3/bashcomplete/)
* finding [application folers](http://click.pocoo.org/3/utils/#finding-application-folders)

---

# JSON vs YAML vs XML vs INI vs TOML vs ...

JSON5 is a proposed extension to JSON

(https://news.ycombinator.com/item?id=7325735)

* JSON5

* OGDL

* CSON

---

# anyconfig

## configuration files in any formats

* JSON w/ json or simplejson
* YAML w/ PyYAML
* Ini w/ configparser
* XML w/ lxml or ElementTree (experimental)

---

# ... and many places

```python
cfg1 = anyconfig.load(["/etc/hn/hn.ini", "~/hn.ini"], merge=MS_REPLACE)
```

## mixed formats

```python
cfg2 = anyconfig.load(["/etc/hn/hn.ini", "~/hn.json"], merge=MS_DICTS)
```

## load all and merge

```python
cfg3 = anyconfig.load(["/etc/hn/*.yaml"], merge=MS_DICTS_AND_LISTS)
```

---

# Sphinx

## create intelligent and beautiful documentation

* easy publishing http://pythonhosted.org/hackernews-cli/
* waiting for [autodoc - click integration](https://github.com/mitsuhiko/click/pull/234)
* workaround with [sphinxcontrib-autorun](https://pypi.python.org/pypi/sphinxcontrib-autorun)

---

# ... and write docs only once

```rst
.. runblock:: console

$ hn comment --help
```

## renders to

```bash
$ hn comment --help
Usage: hn comment [OPTIONS] STORY_ID

comment story on HackerNews

Options:
  --help  Show this message and exit.
```

---

# vcversioner

## version numbers from version control

### configured in ``setup.py``

```python
setup(
    vcversioner={
        'version_module_paths': ['hncli/_version.py'],
    },
```

```python
from hncli._version import __version__
```

---

# Python Packaging

## hate, hate, hate everywhere

```bash
$ pip install hackernews-cli
```

???
error: could not create '/usr/local/lib/python2.7/dist-packages/': Permission denied

```bash
$ sudo pip install hackernews-cli
```

???
wrong global version of requests :/

```bash
$ sudo pip install virtualenv
$ virtualenv hackernews-cli
$ source hackernews-cli/bin/activate
$ pip install hackernews-cli
$ ln -s hackernews-cli/bin/hn ~/bin/hn
```

---

# PEX

## self-contained executable Python virtual environments

```bash
inside_pex$ tree -L 2 -a
.
├── .deps
│   ├── anyconfig-0.0.5-py2-none-any.whl
│   ├── beautifulsoup4-4.3.2-py2-none-any.whl
│   ├── click-3.3-py2.py3-none-any.whl
│   ├── HackerNews-2.0.0-py2-none-any.whl
│   ├── hackernews_cli-0.0.1-py2-none-any.whl
│   └── requests-2.4.3-py2.py3-none-any.whl
└── __main__.py
```

---

# Contributor Experience

---

# Develop, Test and Build

## How do I get up and running in development?

## How do I make sure my new features didn't break old functionality?

---
class: center, middle

# CI, CI, CI, ... CD!

![Failed build in Travis CI](failing_travis.png)

---

# Argue for Code Style

![PR Review with PEP8 requirements](pep8_comment.png)

???
automation!

## Prospector

### analyse Python code and output information about errors, potential problems, convention violations and complexity

---
class: middle, center

# [github.com/](https://github.com/kamilchm/developer-experience)
# [kamilchm/](https://github.com/kamilchm/developer-experience)
# [developer-experience](https://github.com/kamilchm/developer-experience)