PyCon 2013 : Scripting to PyPi to GitHub and More

Script to PyPi to Github

@__mharrison__
http://hairysun.com

About Me

● 12 years Python
● Worked in HA, Search, Open Source, BI

and Storage
● Author of multiple Python Books

Continuums

More like perl-TMTOWTDI

Agenda
● Project Development
– Versioning
– Configuration
– Logging
– File input
– Shell invocation
● Environment Layout * virtualenv * pip
● Project layout

Agenda (2)
● Documentation
● Automation/Makefile
● Packaging
– setup.py
– PyPi
● Testing
● Github
● Travis CI
● Poachplate

Warning
● Starting from basic Python knowledge
● Hands on

– (short) lecture

– (short) code

– repeat until time is gone

Project

Create pycat. Pythonic implementation of
cat

hello world cat.py

import sys
for line in sys.stdin:
print line,

hello world - Python 3

import sys
print (line, end='')

2 or 3?

● Better legacy/library support for 2
● Possible to support both

hello world

import sys
sys.stdout.write(line)

Layout
Can depend on distribution mechanism:
● Single file

● Zip file
– Python entry point

– Splat/run
● System package
● PyPi/Distribute/pip package

Single File

● chmod and place in $PATH
● add #!/usr/bin/env python

Single File (2)

● No reuse

Zip File

● PYTHONPATH=cat.zip python -m
__main__
● tar -zxvf cat.zip; cd cat;
python cat.py

Zip File (2)

● No reuse
● No stacktrace

System Package

● emerge -av qtile (rpm|apt|brew)

System Package (2)
● Requires root
● At mercy of packager (maybe worse than

PyPi)
● Reuse

● Limited to single version
● python -m modulename

Pip Package

“Best practice” is combo of:
● Distribute

● Virtualenv
● Pip

Pip Package (2)

$ virtualenv catenv
$ source catenv/bin/activate
$ pip install pycat

Pip Package (3)

● Multiple versions
● Reuse

● Effort to create setup.py

Minimal Example Layout
Project/
README.txt
project/
__init__.py
other.py
...
setup.py

Better Example Layout
Project/
.gitignore
doc/
Makefile
index.rst
README.txt
Makefile
bin/
runfoo.py
project/
__init__.py
other.py
...
setup.py

Assignment

create layout for
cat.py

Versioning

http://semver.org
Formal spec for versioning projects

Python Versioning

PEP 386
N.N[.n]+[{a|b|c}N[.N]+][.postN][.devN]
1.0a1 < 1.0a2 < 1.0b2.post345

setup.py

from distutils.core import setup

setup(name='PyCat',....
version='1.0')

Where to store version?

In module.__version__ (might cause
importing issues)

Version

If using Sphinx for docs, be sure to update:
docs/
conf.py

argparse

ap = argparse.ArgumentParser(version='1.0')
...
ap.print_version()

Assignment

Add version to project

● Python Configuration
– Django (settings.py)

– Python (site.py, setup.py)
● JSON/YAML
– Google App Engine
● Environment Variables
– Python (PYTHONPATH)
● .ini (ConfigParser, ConfigObj)
– matplotlib
– ipython
● Command line options (argparse)
● Sqlite blob
● Shelve/pickle blob

Configuration (2)

Are not mutually exclusive

Configuration (3)
(Unix) Hierarchy:
● System rc (run control) (/etc/conf.d)
● User rc (~/.config/app/...)
● Environment variables
● Command line options
http://www.faqs.org/docs/artu/ch10s02.html
Filesystem Hierarchy Standard:
http://www.pathname.com/fhs/

Configuration (4)

● Plain text config is easily approachable
● Careful with Python config on process

run by root

Assignment

Add configuration -n to
show line numbers

Logging

logging module provides feature-rich
logging

Logging (2)

import logging

logging.basicConfig(level=logging.ERROR,
filename='.log')
...
logging.error('Error encountered in...')

Assignment

Add configuration
--verbose to log file
being “catted”

“Files”

Dealing with?
● Filename

● file object
● string data

Filename

Somewhat analogous to an Iterable.
● Can open/iterate many times

● Implementation depends on file
● Need to manage closing file

File Object

Somewhat analogous to an Iterator.
● Can iterate once (unless seeked)
● Can accept file, StringIO, socket,
generator, etc
● Memory friendly - scalable

String Data

No iterator analogy.
● Memory hog - less scalable

Stdlib Examples
Module String Data File Filename
json loads load
pickle loads load
xml.etree.Element fromstring parse parse
Tree
xml.dom.minidom parseString parse parse
ConfigParser cp.readfp cp.read(filenames
)
csv reader DictReader
pyyaml 3rd party load, safe_load load, safe_load

Stdlib Take-aways

● mostly functions
● file interface is required, others optional

● parse or load

Example
>>> import sys

>>> def parse(fin):
... for line in upper(fin):
... sys.stdout.write(line)

>>> def upper(iterable):
... for item in iterable:
... yield str(item).upper()

Create file to parse

>>> with open('/tmp/data', 'w')
as fout:
... fout.write('line1n ')
... fout.write('line2n ')

Filename to file
>>> filename = '/tmp/data'
>>> with open(filename) as fin:
... parse(fin)
LINE1
LINE2

String data to file
>>> data = "stringn datan "
>>> import StringIO
>>>
parse(StringIO.StringIO(data))
STRING
DATA

Parse Iterable

>>> data = ['foon ', 'barn ']
>>> parse(data)
FOO
BAR

More file benefits

● Combine with generators to filter, tweak
● Easier to test

Assignment

Add a parse function

Reading output

>>> import subprocess
>>> p = subprocess.Popen('id -u', shell=True,
stdout=subprocess.PIPE, stderr=subprocess.PIPE)
>>> p.stdout.read()
'1000n'
>>> p.returncode # None means not done
>>> print p.wait()
0

Feeding stdin
Can use communicate or
p2.stdin.write w/ flush/close.
>>> p2 = subprocess.Popen('wc -l', shell=True,
stdout=subprocess.PIPE, stdin=subprocess.PIPE,
stderr=subprocess.PIPE)
>>> out, err = p2.communicate('foon barn ')
#p.stdin.flush()

>>> out
'2n'
>>> p2.returncode
0

Chaining scripts.
Chaining is pretty straightforward make sure to close stdin
http://stackoverflow.com/questions/1595492/blocks-send-input-to-python-subpr
ocess-pipeline
>>> p3 = subprocess.Popen('sort', shell=True,
... stdout=subprocess.PIPE,
... stdin=subprocess.PIPE)
>>> p4 = subprocess.Popen('uniq', shell=True,
... stdout=subprocess.PIPE,
... stdin=p3.stdout,
... close_fds=True) # hangs w/o close_fds

>>> p3.stdin.write('1n 2n 1n ')
>>> p3.stdin.flush(); p3.stdin.close();
>>> p4.stdout.read()
'1n2n'

Chaining scripts and python
cat 0-2, add 10 to them (in python) and wc
-l results.
>>> import os
>>> p5 = subprocess.Popen('cat', shell=True,
stdout=subprocess.PIPE, stdin=subprocess.PIPE, close_fds=True)
>>> def p6(input):
... ''' add 10 to line in input '''
... for line in input:
... yield '%d%s ' %(int(line.strip())+10, os.linesep)

Chaining scripts and python
(2)
>>> p7 = subprocess.Popen('wc -l', shell=True,
stdout=subprocess.PIPE, stdin=subprocess.PIPE, close_fds=True)
>>> [p5.stdin.write(str(x)+os.linesep) for x in xrange(3)]
>>> p5.stdin.close()
>>> [p7.stdin.write(x) for x in p6(p5.stdout.xreadlines())]
>>> p7.stdin.close()
>>> p7.stdout.read()
'3n'

Python Environment

● System Python or “Virtual” Python
● Installation method

Which Python

System Python
● Requires root

● Only one version of library
● System packages may be out of date

Which Python (2)

“Virtual” Python
● Runs as user

● Specify version
● Sandboxed from system

● Create multiple sandboxes

Which Python (3)

Install virtualenv

virtualenv
Installation:
● System package $ sudo apt-get install
python-virtualenv
● With pip $ pip install virtualenv
● $ easy_install virtualenv
● $ wget
https://raw.github.com/pypa/virtualenv/master/
virtualenv.py; python virtualenv.py

virtualenv (2)

Create virtual environment:
$ virtualenv env_name

Directory Structure
env_name/
bin/
activate
python
pip
lib/
python2.7/
site-packages/

virtualenv (3)

Activate virtual environment:
$ source env_name/bin/activate

virtualenv (4)

Windows activate virtual environment:
> pathtoenvScriptsactivate

May require PS C:>
Set-ExecutionPolicy AllSigned

virtualenv (5)

Comes with pip to install packages:
$ pip install sqlalchemy

virtualenv (6)

$ which python # not /usr/bin/python
/home/matt/work/courses/script-pypi-github/env/b
in/python

virtualenv (7)
>>> sys.path
['', ...,
'/home/matt/work/courses/script-py
pi-github/env/lib/python2.7/site-p
ackages']

virtualenv (8)

Use deactivate shell function to reset
PATH:
$ deactivate

Assignment

create virtualenv env

pip
Recursive Acronym - Pip Installs Packages
● install

● upgrade
● uninstall

● “pin” versions
● requirements.txt

pip (2)

Install:
$ pip install sqlalchemy

pip (3)

Upgrade:
$ pip install --upgrade sqlalchemy

pip (4)

Uninstall:
$ pip uninstall sqlalchemy

pip (5)

“Pin” version:
$ pip install sqlalchemy==0.7

pip (6)

Requirements file:
$ pip install -r requirements.txt

pip (7)

Requirements file $ cat requirements.txt:
sqlalchemy==0.7
foobar
bazlib>=1.0

pip (8)

Create requirement file from env:
$ pip freeze > req.txt

pip (9)

● pip docs say to install from virtualenv
● virtualenv docs say to install from pip

pip (10)
Install from directory:
pip install --download packages -r
requirements.txt
pip install --no-index
--find-links=file://full/path/to/p
ackages -r requirements.txt

distribute, setuptools,
distutils
● pip wraps distribute adds uninstall,
req.txt
● distribute fork of setuptools
● setuptools unmaintained, adds eggs,
dependencies, easy_install
● distutils stdlib packaging library

Assignment

use pip to install
package from internet

.gitignore
*.py[cod]

# C extensions
*.so

# Packages
*.egg
*.egg-info
dist
build
eggs
parts
bin
var
sdist

develop-eggs
.installed.cfg
.gitignore
lib
lib64
__pycache__

# Installer logs
pip-log.txt

# Unit test / coverage reports
.coverage
.tox
nosetests.xml

# Translations
*.mo

https://github.com/github/gitignore

.gitignore (2)

See blaze-core for example of C and
Docs.
https://github.com/ContinuumIO/blaze-cor
e

From requests:

.coverage
.gitignore (3)
MANIFEST
coverage.xml
nosetests.xml
junit-report.xml
pylint.txt
toy.py
violations.pyflakes.txt
cover/
docs/_build
requests.egg-info/
*.pyc
*.swp
env/
.workon
t.py
t2.py

https://github.com/kennethreitz/requests

●
Other(for django)
localsettings.py
tips
● *~ (emacs)
● Run git status and add outliers to
.gitignore
● Make settings global:
git config --global core.excludesfile
Python.gitignore
git config --global core.excludesfile
Python.gitignore

Assignment

add (premptive)
.gitignore

Documentation

Two types:
● Developer docs (README, INSTALL,

HACKING, etc)
● End user

Developer

README - main entry point for project
● Brief intro
● Links/Contact

● License

README

For github integration name it README.rst
or README.md

LICENSE

Include text of license. Templates at
http://opensource.org/licenses/index.html

Licensing
Some include dunder meta in project docstring (requests
__init__.py):
:copyright: (c) 2013 by Kenneth Reitz.
:license: Apache 2.0, see LICENSE for more
details.

(note IANAL)

Licensing (2)
Some include dunder meta in project (requests
__init__.py):
__title__ = 'requests'
__version__ = '1.1.0'
__build__ = 0x010100
__author__ = 'Kenneth Reitz'
__license__ = 'Apache 2.0'
__copyright__ = 'Copyright 2013 Kenneth Reitz'

(note IANAL)

Other files

● AUTHORS
● HISTORY/CHANGELOG

● TODO

Assignment

create simple README

End User Docs

Sphinx is a tool that makes it easy to create
intelligent and beautiful documentation,
written by Georg Brandl and licensed
under the BSD license.
http://sphinx-doc.org

Suggested setup

Project/
doc/
# sphinx stuff
Makefile

Sphinx in 4 Lines

$ cd docs
$ sphinx-quickstart
$ $EDITOR index.rst
$ make html

Assignment

write docs at a later
time :)

Running commands often:
● nosetests (plus options)
Motivation
● create sdist
● upload to PyPi
● create virtualenv
● install dependencies
● cleanup cruft
● create TAGS
● profile
● sdist
● PyPi - register and upload
● creating pngs from svgs
● docs
● Python 3 testing
● etc...

Makefile

● Knows about executing (build)
commands
● Knows about dependencies

Example

To test:
● Make virtualenv

● install code dependencies
● install nose (+coverage)

● run tests

Clean checkout
$ make test
vs
$ virtualenv env
$ env/bin/activate
$ pip install -r deps.txt
$ pip install nose coverage.py
$ nosestests

Enough make
knowledge to be
dangerous

Makefile (1)
Syntax of Makefile:
file: dependentfile
<TAB>Command1
...
<TAB>CommandN

Makefile (2)
Running (runs Makefile by default):
$ make file
# will build dependentfile if
necessary
# then build file

Makefile (3)

Example:
foo: foo.c foo.h
<TAB>cc -c foo.c
<TAB>cc -o foo foo.o

Makefile (4)
Running (echoes commands by default -s
for silent):
$ make
cc -c foo.c
cc -o foo foo.o

Makefile (5)

Subsequent runs do nothing:
$ make
make: `foo' is up to date.

Makefile (6)
Add a clean command:
.PHONY: clean

clean:
<TAB>rm foo.o foo

Makefile (7)

Since clean isn't a file, need to use .PHONY
to indicate that to make. (If you had a file
named clean it wouldn't try to build it).

Makefile (8)
(Simply Expanded) Variables (expanded when set):
BIN := env/bin
PY := $(BIN)/python
NOSE := $(BIN)/nosetests

.PHONY: build
build: env
<TAB>$(PY) setup.py sdist

Makefile (9)
(Recursively Expanded) Variables (expanded when used):
FILE = foo
DATA = $(FILE)

# If DATA expanded would be foo

FILE = bar
# If DATA expanded would be bar

Makefile (10)

Shell functions:
.PHONY: pwd
pwd:
<TAB>pushd /etc

Makefile (11)
Invoking:
$ make pwd
pushd /etc
make: pushd: Command not found
make: *** [pwd] Error 127

(pushd is a bash function)

Makefile (12)
Shell functions:
SHELL := /bin/bash

.PHONY: pwd
pwd:
<TAB>pushd /etc

Makefile (13)
Multiple commands:
SHELL := /bin/bash

.PHONY: pwd
pwd:
<TAB>pushd /etc
<TAB>pwd
<TAB>popd

Makefile (14)
Multiple commands:
$ make pwd
pushd /etc
/etc /tmp/foo
pwd
/tmp/foo
popd
/bin/bash: line 0: popd: directory stack empty

Makefile (15)

Each tab indented command runs in its
own process. Use ; and put in one line or
use for line continuation

Makefile (16)
Multiple commands (use line continuation ):

SHELL := /bin/bash

.PHONY: pwd2
pwd2:
<TAB>pushd /etc;
<TAB>pwd;
<TAB>popd

Makefile (17)

Shell variables:
.PHONY: path
path:
<TAB>echo $PATH

Makefile (18)

Make thinks they are make variables:
$ make path
echo ATH
ATH

Makefile (19)

$ needs to be escaped with $:
.PHONY: path
path:
<TAB>echo $$PATH

Makefile (18)

Now it works:
$ make path
echo $PATH
/tmp/maketest

Makefiles for Python
Projects

Inspired by Rick Harding's
Talk

http://pyvideo.org/video/1354/starting-you
r-project-right-setup-and-automation
https://github.com/mitechie/pyohio_2012

Makefile for Python

Make virtualenv:
env:
<TAB>virtualenv env

Makefile for Python (2)
Make dependencies:
.PHONY: deps
deps: env
<TAB>$(PIP) install -r
requirements.txt

Makefile for Python (3)
Testing with nose:

.PHONY: test
test: nose deps
<TAB>$(NOSE)

# nose depends on the nosetests binary
nose: $(NOSE)
$(NOSE): env
<TAB>$(PIP) install nose

Contrary Opinions

“Dynamic languages don't need anything
like make, unless they have some
compile-time interface dependencies
between modules”
http://stackoverflow.com/questions/758093
9/why-are-there-no-makefiles-for-automati
on-in-python-projects

Other options

● paver
● fabric

● buildout

setup.py overloaded

● create sdist (source distribution)
● upload to pypi

● install package

setup.py wart

require keyword of distutils doesn't
download reqs only documents them. Use
requirements.txt in combo with pip.

setup.py example
From requests:
setup(
name='requests',
version=requests.__version__,
description='Python HTTP for Humans.',
long_description=open('README.rst').read() +
'nn' +
open('HISTORY.rst').read(),
author='Kenneth Reitz',
author_email='me@kennethreitz.com',
url='http://python-requests.org',

setup.py example (2)
packages=packages,
package_data={'': ['LICENSE', 'NOTICE'],
'requests': ['*.pem']},
package_dir={'requests': 'requests'},
include_package_data=True,
install_requires=requires,
license=open('LICENSE').read(),
zip_safe=False,

setup.py example (3)
classifiers=(
'Development Status :: 5 - Production/Stable',
'Intended Audience :: Developers',
'Natural Language :: English',
'License :: OSI Approved :: Apache Software License',
'Programming Language :: Python',
'Programming Language :: Python :: 2.6',
'Programming Language :: Python :: 3',
# 'Programming Language :: Python :: 3.0',
),
)

setup.py modules

If project consists of a few modules this
may be easiest

setup.py packages

Need to explicitly list all packages, not just
root

setup.py scripts

Add executable Python files here

setup.py non-Python files

● add files to MANIFEST.in (include in
package)
● add files to package_data in setup.py
(include in install) Not recursive

MANIFEST.in language
● include|exclude pat1 pat2 ...
● recursive-(include|exclude) dir pat1 pat2 ...
● global-(include|exclude) dir pat1 pat2 ...
● prune dir
● graft dir
http://docs.python.org/release/1.6/dist/sdist-cmd.html#sdist-c
md

setup.py classifiers

Almost 600 different classifiers.
Not used by pip to enforce versions. For UI
only

Create sdist

$ python setup.py sdist

PyPi

Validate setup.py:
$ python setup.py check

PyPi Register

Click on “Register” on right hand box
https://pypi.python.org/pypi?%3Aaction=re
gister_form

PyPi Upload

$ python setup.py sdist register
upload

PyPi Upload (2)
$ python setup.py sdist register upload
...
Creating tar archive
removing 'rst2odp-0.2.4' (and everything under it)
running register
running check
We need to know who you are, so please choose either:
1. use your existing login,
2. register as a new user,
3. have the server generate a new password for you (and email it to you),
or
4. quit
Your selection [default 1]:
1

PyPi Upload (3)
Username: mharrison
Password:
Registering rst2odp to http://pypi.python.org/pypi
Server response (200): OK
I can store your PyPI login so future submissions will be faster.
(the login will be stored in /home/matt/.pypirc)
Save your login (y/N)?y
running upload
Submitting dist/rst2odp-0.2.4.tar.gz to http://pypi.python.org/pypi
Server response (200): OK

PyPi Note

Though PyPi packages are signed there is
no verification step during package
installation

Non PyPi URL

$ pip install --no-index -f
http://dist.plone.org/thirdparty/
-U PIL

Personal PyPi

https://github.com/benliles/djangopypi

PyPi
Makefile integration:
# --------- PyPi ----------
.PHONY: build
build: env
<TAB>$(PY) setup.py sdist

.PHONY: upload
upload: env
<TAB>$(PY) setup.py sdist register upload

Testing

Add tests to your project

Testing (2)

● use doctest or unittest

Testing (3)
Use nose to run:
$ env/bin/nosetests
..
-------------
Ran 2 tests in 0.007s

OK

Testing (4)
Makefile integration:
NOSE := env/bin/nosetests
# --------- Testing ----------
.PHONY: test
test: nose deps
<TAB>$(NOSE)

# nose depends on the nosetests binary
nose: $(NOSE)
$(NOSE): env
<TAB>$(PIP) install nose

Github

Just a satisfied user

Why Github?

Not bazaar nor mercurial

Why Github? (2)

Code is a first class object

Github

Don't check in keys/passwords!
http://ejohn.org/blog/keeping-passwords-i
n-source-control/#postcomment

A Branching Strategy

http://github.com/nvie/gitflow

Travis CI

CI (continuous integration) for Github

Travis CI (2)

Illustrates power of (web) hooks

5 Steps
● Sign-in with github
● Sync repos on Profile page

● Enable repo
● Create a .travis.yml file on github
● Push a commit on github

travis.yml
language: python
python:
- "3.3"
- "2.7"
- "2.6"
- "pypy"
# command to run tests
script: make test

More Info

http://about.travis-ci.org/

poachplate

Example of most of what we have talked
about today
https://github.com/mattharrison/poachplat
e

That's all

Questions? Tweet or email me
matthewharrison@gmail.com
@__mharrison__
http://hairysun.com

PyCon 2013 : Scripting to PyPi to GitHub and More

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