Python

flake8 skip lines

If specific lines should not be linted i.e. long URLs over 80 chars
just append following comment to your line that should be ignored
# noqa

argparse

import sys
import argparse

parser = argparse.ArgumentParser(description='Put some different arguments')
parser.add_argument('--storstring', '-s', action='store', dest='string', required=True,
  help='Put some string in here. This value is also required/mandatory')
parser.add_argument('--true', '-t', action='store_true', dest='bool', default=False,
  help='If set variable is set to true')
parser.add_argument('--append', '-a', action='append', dest='append', default=[]
  help='Put strins into array. this can be used multiple times')
args = parser.parse_args()

# Values can be accesed via args.string, args.bool, args.append

# Print help when no args given
if len(sys.argv)==1:
  parser.print_help()
  sys.exit(1)

system call

import os

com = os.popen("<SHELL COMMAND>").read()
for c in com:
  print(c)

ternary operator

variable = variable if variable else self.variable

merge dict

by updating the dictionary:

x = {'a': 1, 'b': 2}
y = {'b': 3, 'c': 4}

x.update(y)
print(x)

Using ** operator:

x = {'a': 1, 'b': 2}
y = {'b': 3, 'c': 4}

z = {**x, **y}
print(z)

mixed:

x = {'a': 1, 'b': 2}
y = {'b': 3, 'c': 4}

print({**x, 'foo': 1, 'bar': 2, **y})


## Ensure OpenStack env is set

```python
if not os.environ.get('OS_AUTH_URL') or not os.environ.get('OS_DOMAIN_NAME') or not os.environ.get('OS_PROJECT_NAME') or not os.environ.get('OS_PASSWORD') or not os.environ.get('OS_USERNAME'):
  print("missing OpenStack Environment variables! Plase source openrc")
  exit(1)

Build python package

Directory structure

/python-my-package
    /my-package
        __init__.py
        __main__.py
        submodule1.py
        submodule2.py
        submodule3.py
.gitignore
.gitlab-ci.yml
README.md
setup.py

.gitignore

build/
dist/
*.egg-info
__pycache__

setup.py

import setuptools, os

with open("README.md", "r") as fh:
    long_description = fh.read()

def get_version(version='9999.999.99-devel'):
  if 'CI_COMMIT_SHORT_SHA' in os.environ:
    version = os.environ['CI_COMMIT_SHORT_SHA']
  if 'CI_COMMIT_TAG' in os.environ:
    version = os.environ['CI_COMMIT_TAG']
  if 'CUSTOM_VERSION' in os.environ:
    version = os.environ['CUSTOM_VERSION']
  return version

setuptools.setup(
  name='python-my-package',
  version=get_version(),
  author="Me Myself And I",
  author_email="me@myself.and.i",
  description="My first python package",
  long_description=long_description,
  long_description_content_type="text/markdown",
  url="https://gitlab.der-jd.de/python/python-my-package",
  license='MIT',
  packages=setuptools.find_packages(),
  install_requires=['requests', 'ptable', 'argparse', 'configparser'],
  entry_points={"console_scripts": ["my-package = my-package.cli:main"]},
  classifiers=[
    "Operating System :: POSIX :: Linux",
    "Programming Language :: Python :: 3",
    "Programming Language :: Python :: 3.7",
    "License :: OSI Approved :: MIT License",
  ],
)

build package

python setup.py sdist

.gitlab-ci.yml

---

default:
  image: python:latest
  stages:
    - build
    - test
    - release
  artifacts:
    when: on_success
    paths:
      - dist/*.tar.gz

# build whl, deb and rpm
build:pip:
  stage: build
  script:
    - pip install setuptools wheel
    - python setup.py sdist
# build:deb:
#   stage: build
#   scripts:
#     - debian build
# build:rpm:
#   stage: build
#   scripts:
#     - rpm build

test:
  stage: test
  scripts:
    - pip install ./
    # - dpkg install *.deb
    # - yum install *.rpm

release:
  stage: release
  only:
    - tags

---

Last update: January 15, 2021