This section covers installation of lim.

Production use of lim should take advantage of released versions on PyPi. Testing of development versions that have not yet been released can be installed from the GitHub repository’s master or develop branch. Development use (e.g., for creating pull requests with bug fixes and new features) will generally install from a local clone of the GitHub repository. Each of these are described below.

It is generally recommended to use a Python virtual environment to isolate installation of third-party open source packages that could potentially break the default operating system installation of Python by accidentally upgrading incompatible versions of necessary packages, or when packages required by specific open source modules require a more recent version of Python than the one installed with your operating system. E.g., the python_secrets package requires Python 3.6 or newer, while some operating systems come with Python 2.7 or Python 3.4.

There are two ways to handle this situation.

  1. If you intend on doing development and testing of the lim Python source code itself, it is best to use a Python virtual environment that you maintain manually. This is a little more complicated, but you will find it better suited for development.

  2. If you simply need to run the lim CLI on an analysis workstation in a “production” sense, there is an easier way to manage the virtual environment and package installation more like you would with an operating system package manager.

The second, simpler method, will be covered first.

Production (non-development) installation

The program pipx is the easiest way to install a Python package including command line scripts to run them as stand-alone commands in their own virtual environments (without having to know much about virtual environments). Programs installed by pipx are called apps.

pipx manages creating the virtual environment and creating links to a common runtime directory that you add to your $PATH to run them.

On a Mac running Darwin, Homebrew is the easiest way to install pipx:

$ brew info pipx
pipx: stable (bottled), HEAD
Execute binaries from Python packages in isolated environments
/usr/local/Cellar/pipx/ (125 files, 660.3KB) *
  Poured from bottle on 2020-05-27 at 10:21:20
==> Dependencies
Required: python@3.8 ✔
==> Options
    Install HEAD version
==> Analytics
install: 2,090 (30 days), 4,963 (90 days), 8,568 (365 days)
install-on-request: 2,093 (30 days), 4,963 (90 days), 8,553 (365 days)
build-error: 0 (30 days)

Install pipx as follows:

$ brew install pipx
Updating Homebrew...
==> Auto-updated Homebrew!
==> Downloading
Already downloaded: /Users/dittrich/Library/Caches/Homebrew/downloads/6251803fbe228622581468fc08e6f781172e7083c958e424693b471cb1953d1c--pipx-
==> Pouring pipx-
🍺  /usr/local/Cellar/pipx/ 92 files, 530.9KB

Now install lim as an app using the package name lim-cli.

$ pipx install lim-cli
  installed package lim-cli 20.5.2, Python 3.8.2
  These apps are now globally available
    - lim
done! ✨ 🌟 ✨

You can get information about the path where apps are located, the parent package name and current release version, the version of Python the apps use, the apps (scripts) installed from the parent package name, etc.

$ pipx list
venvs are in /Users/dittrich/.local/pipx/venvs
apps are exposed on your $PATH at /Users/dittrich/.local/bin
   package ansible 2.9.9, Python 3.8.2
    - ansible
    - ansible-config
    - ansible-connection
    - ansible-console
    - ansible-doc
    - ansible-galaxy
    - ansible-inventory
    - ansible-playbook
    - ansible-pull
    - ansible-test
    - ansible-vault
   package asciinema 2.0.2, Python 3.8.2
    - asciinema
   package blockdiag 2.0.1, Python 3.8.2
    - blockdiag
   package bump2version 1.0.0, Python 3.8.2
    - bump2version
    - bumpversion
   package lim-cli 20.5.2, Python 3.8.2
    - lim
   package sphinx 3.0.4, Python 3.8.2
    - sphinx-apidoc
    - sphinx-autogen
    - sphinx-build
    - sphinx-quickstart
   package twine 3.1.1, Python 3.8.2
    - twine

For more information on capabilities of pipx, see the project web site:

Development and testing installation

Source directory setup

Start by cloning the lim code repository into your Git base directory.

$ git clone ~/git/lim-cli
Cloning into '/home/dittrich/git/lim-cli'...
remote: Enumerating objects: 174, done.
remote: Counting objects: 100% (174/174), done.
remote: Compressing objects: 100% (95/95), done.
remote: Total 1397 (delta 102), reused 132 (delta 68), pack-reused 1223
Receiving objects: 100% (1397/1397), 264.53 KiB | 0 bytes/s, done.
Resolving deltas: 100% (920/920), done.
Checking connectivity... done.
$ cd ~/git/lim-cli
$ tree -L 1
├── AUTHORS.rst
├── ChangeLog
├── HISTORY.rst
├── LICENSE-2.0.txt
├── Makefile
├── README.rst
├── bandit.yaml
├── docs
├── lim
├── requirements.txt
├── setup.cfg
├── test-requirements.txt
├── tests
└── tox.ini

3 directories, 16 files


There is a subdirectory with the same name as the top level directory. The directory lim-cli is the source directory for the Cliff lim CLI application. Unless otherwise specified, the current working directory for example commands will be the top level of the cloned directory, /home/dittrich/git/lim-cli in this case.

Within this source directory, you can then create a virtual environment using a version of Python 3.6 (or higher):

$ /home/dittrich/miniconda3/bin/python3.6 -m venv env
$ tree -L 1 env
├ bin
├ include
├ lib
├ lib64 -> lib
└ pyvenv.cfg

4 directories, 1 file

To activate this virtual environment, source the activation script. Many Linux shell prompts will immediately show the active Python virtual environment as part of the shell prompt, as seen here:

$ type python3
python3 is /home/dittrich/miniconda3/bin/python3
$ source env/bin/activate
(env) $ type python3
python3 is /home/dittrich/git/lim-cli/env/bin/python3
(env) $


It is a good idea to immediately update pip in the new virtual environment, just in case it was out of date.

$ python3 -m pip install -U pip
Cache entry deserialization failed, entry ignored
Collecting pip
  Cache entry deserialization failed, entry ignored
  Downloading (1.5 MB)
    100% |████████████████████████████████| 1.3MB 306kB/s
Installing collected packages: pip
  Attempting uninstall: pip
    Found existing installation: pip 19.3.1
    Uninstalling pip-19.3.1:
      Successfully uninstalled pip-19.3.1
Successfully installed pip-20.1

After cloning the source repository, there are several steps required to install lim and its pre-requisite software packages.

Install pre-requisite software

Required Python packages can be installed using the requirements.txt file.

$ python -m pip install -U -r requirements.txt
Collecting cliff (from -r requirements.txt (line 1))
  Using cached
Collecting gnureadline (from -r requirements.txt (line 2))
6.3.8-cp36-cp36m-manylinux1_x86_64.whl (474kB)
    100% |████████████████████████████████| 481kB 508kB/s
. . .
Successfully installed MarkupSafe-1.1.0 PrettyTable-0.7.2 PyYAML-3.13 Pygments-2.3.1 alabaster-0.7.12 asn1crypto-0.24.0 attrs-18.2.0
babel-2.6.0 bcrypt-3.1.5 certifi-2018.11.29 cffi-1.11.5 chardet-3.0.4 cliff-2.14.0 cmd2-0.9.6 colorama-0.4.1 coloredlogs-10.0 cryptog
raphy-2.4.2 docutils-0.14 executor-21.3 fasteners-0.14.1 filelock-3.0.10 gnupg-2.3.1 gnureadline-6.3.8 humanfriendly-4.17 idna-2.8 im
agesize-1.1.0 jinja2-2.10 lxml-4.2.5 monotonic-1.5 naturalsort-1.5.1 numpy-1.15.4 packaging-18.0 pandas-0.23.4 paramiko-2.4.2 pbr-5.1
.1 pluggy-0.8.0 property-manager-2.3.1 psutil-5.4.8 py-1.7.0 pyasn1-0.4.4 pycparser-2.19 pynacl-1.3.0 pyparsing-2.3.0 pyperclip-1.7.0
 python-dateutil-2.7.5 python-secrets-18.11.5 pytz-2018.7 requests-2.21.0 six-1.12.0 snowballstemmer-1.2.1 sphinx-1.8.2 sphinxcontrib
-websupport-1.1.0 sshtunnel-0.1.4 stevedore-1.30.0 toml-0.10.0 tox-3.6.1 update-dotdee-5.0 urllib3-1.24.1 verboselogs-1.7 virtualenv-
16.1.0 wcwidth-0.1.7 xkcdpass-1.17.0 yamlreader-3.0.4

Configure a python_secrets environment

The python_secrets program is used to store secrets (e.g., an Amazon AWS API key for a limited AWS user, passwords, etc) and other related variables (e.g., path to SSH private key), and the terraform state files (which will also contain copies of secrets). These variables and files are organized into directory trees known as environments. The name of the environment we want to use for the purposes of this documentation is going to be lim.

$ psec environments path
$ psec environments tree lim
environment "lim" does not exist

Explicitly set the default python_secrets environment identifier for use in the Git source repository.

$ pwd
$ /home/dittrich/git/lim-cli
$ psec environments default lim
default environment set to "lim"


There is a irritating side-effect of using Cliff, which loads commands dynamically using the Python packaging mechanism. You can’t just use the normal Python develop mechanism to run code directly from the current working directory. You need to install the full package into the current Python environment with make install-active and then the lim app will load the current versions of commands properly.

There may be another way to do this, but it isn’t obvious and hasn’t been identified yet. This mechanism, though a little tedious, does work.

To update the user documentation as you code–you do document your code well, right? right?–you can either build the Sphinx documentation as part of the make test tasks (one of which is testing Sphinx generation), or you can do it manually with make docs.

$ make docs
(cd docs && make clean html)
rm -rf _build/*
sphinx-build -b html -d _build/doctrees   . _build/html
Running Sphinx v2.1.2
making output directory... done
building [mo]: targets for 0 po files that are out of date
building [html]: targets for 8 source files that are out of date
updating environment: 8 added, 0 changed, 0 removed
reading sources... [100%] usage
looking for now-outdated files... none found
pickling environment... done
checking consistency... done
preparing documents... done
writing output... [100%] usage
generating indices... genindex
writing additional pages... search
copying static files... done
copying extra files... done
dumping search index in English (code: en) ... done
dumping object inventory... done
build succeeded, 5 warnings.

The HTML pages are in _build/html.

Build finished. The HTML pages are in _build/html.

If you are on a Mac, you can then open the document in your default browser with open docs/_build/html/index.html.