How To Use This Template

WARNING: This is a PROOF-OF-CONCEPT template to help you quickly get started with writing charms built on top of the Operator Framework. It uses charmcraft to build the final charm zip file. More info on how to use charmcraft in Juju Discourse. Please note that this template has neither been reviewed nor adopted by the Charmcraft team so use this template at your own risk.

Browse to this template's GitHub page then click on the green "Use this template" button. Follow the steps on GitHub to create a freshly squeezed charm project! If you need more information before diving in, kindly refer to this GitHub documentation.

Next, run the following command to know which places you need to customize:

make changes

Change every line of every file listed in the output until re-running the command does not yield anything else. Afterwards, delete this section and then proceed to the Developer Guide section below for more instructions. Good luck!

ChangeMe Charm

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Quick Start

Test, build, and deploy the charm:

make test build && \
    juju deploy ./changeme.charm --resource changeme-image=changeme/changeme:v1.2.3

Developer's Guide

Prepare Your Development Environment

1. Install pyenv so that you can test with different versions of Python

curl -L https://raw.githubusercontent.com/yyuu/pyenv-installer/master/bin/pyenv-installer | bash

2. Append the following to your ~/.bashrc then log out and log back in

export PATH="$HOME/.pyenv/bin:$PATH"
eval "$(pyenv init -)"
eval "$(pyenv virtualenv-init -)"

3. Install development packages

sudo apt install build-essential libssl-dev zlib1g-dev libbz2-dev \
    libreadline-dev libsqlite3-dev wget curl llvm libncurses5-dev libncursesw5-dev \
    xz-utils tk-dev libffi-dev liblzma-dev python3-openssl git

4. Install Python 3.5, 3.6 and 3.7

pyenv install 3.5.9
pyenv install 3.6.10
pyenv install 3.7.7

NOTE: For more available versions, run pyenv install --list

5. Create a virtualenv for this project

export charm_name=changeme
pyenv virtualenv 3.7.7 ${charm_name}-3.7.7
pyenv local ${charm_name}-3.7.7 3.7.7 3.6.10 3.5.9

Your newly created virtualenv should now be activated if your prompt changed to the following:

(changeme-3.5.9) ubuntu@dev-18-04-2:/path/to/your/charm$

Notice the things in parentheses that corresponds to the virtualenv you created in the previous step. This is thanks to the coordination of pyenv-virtualenv and a newly createdd .python-version file in the rootdir of this project.

If you cd .. or cd anywhere else outside your project directory, the virtualenv will automatically be deactivated. When you cd back into the project dir, the virtualenv will automatically be activated.

Install The Dependencies

Install all development and runtime dependencies.

WARNING: Make sure you are using a virtualenv before running this command. Since it uses pip-sync to install dependencies, it will remove any package that is not listed in either dev-requirements.in or setup.py. If you followed the steps in Prepare Your Development Environment above, then you're good.

make dependencies

Adding A Development Dependency

1. Add it to dev-requirements.in and then run make:

echo "foo" >> dev-requirements.in
make dependencies

This will create dev-requirements.txt and then install all dependencies

2. Commit dev-requirements.in and dev-requirements.txt. Both files should now be updated and the foo package installed in your local machine. Make sure to commit both files to the repo to let your teammates know of the new dependency.

git add dev-requirements.*
git commit -m "Add foo to dev-requirements.txt"
git push origin

Adding A Runtime Dependency

1. Add it to runtime_requirements list in setup.py and then run:

make dependencies

This will create requirements.txt and then install all dependencies

2. Commit setup.py and requirements.txt. Both files should now be updated and the foo package installed in your local machine. Make sure to commit both files to the repo to let your teammates know of the new dependency.

git add requirements.txt
git add setup.py
git commit -m "Add bar to requirements.txt"
git push origin

Testing and Building the Charm

After any change in the charm code, you want to ensure that all unit tests pass before building it. This can be easily done by running:

make test build

Viewing the Coverage Report

To view the coverage report, run the tests first and then run:

make coverage-server

This will run a simple web server on port 5000 that will serve the files in the auto-generated htmlcov/ directory. You may leave this server running in a separate session as you run the tests so that you can just switch back to the browser and hit refresh to see the changes to your coverage down to the line of code.

Running the Tests in Multiple Python Versions

More often than not your charm needs to support more than one version of Python. This is where tox comes in. Just run the following to get test results for all Python versions listed in tox.ini's envlist config option

tox

Need to Start Over?

Sigh, don't we all...oh, wait, you mean with the project's state? Oh, well we got you covered there. Just run:

make clean