Loki-k8s docs - contributing

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Contributing to loki-operator

Overview

This documents explains the processes and practices recommended for contributing enhancements to the Loki charm.

  • Generally, before developing enhancements to this charm, you should consider opening an issue explaining your use case.
  • If you would like to chat with us about your use-cases or proposed implementation, you can reach us at Canonical Mattermost public channel or Discourse. The primary author of this charm is available on the Mattermost channel as @jose-masson.
  • It is strongly recommended that prior to engaging in any enhancements to this charm you familiarise your self with Juju.
  • Familiarising yourself with the Charmed Operator Framework. library will help you a lot when working on PRs.
  • All enhancements require review before being merged. Besides the code quality and test coverage, the review will also take into account the resulting user experience for Juju administrators using this charm. Please help us out in having easier reviews by rebasing onto the main branch, avoid merge commits and enjoy a linear Git history.

Setup

A typical setup using snaps, for deployments to a microk8s cluster can be done using the following commands

    sudo snap install microk8s --classic
    microk8s.enable dns storage
    sudo snap install juju --classic
    juju bootstrap microk8s microk8s
    juju create-storage-pool operator-storage kubernetes storage-class=microk8s-hostpath

Developing

Create and activate a virtualenv with the development requirements:

   virtualenv -p python3 venv
   source venv/bin/activate
   pip install -r requirements.txt

Later on, upgrade packages as needed

   pip install --upgrade -r requirements.txt

Testing

All tests can be executed by running tox without arguments.

To run individual test environments:

tox -e prettify  # update your code according to linting rules
tox -e lint  # check your code complies to linting rules
tox -e static # run static analysis
tox -e unit  # run unit tests

Unit tests are implemented using the Operator Framework test harness.

Build

Install the charmcraft tool and build the charm in this git repository:

    charmcraft pack

Code Overview

The core implementation of this charm is represented by the LokiOperatorCharm class. LokiOperatorCharm responds to the following events:

  • loki_pebble_ready: Here we set up pebble layer and start the service
  • relation_joined In this event (Provided by the object LokiPushApiProvider) we set the loki_push_api (http://{self.unit_ip}:{self.charm.port}/loki/api/v1/push) so it can be used by a Consumer charm that uses the LokiPushApiConsumer object.

Both clases LokiPushApiProvider and LokiPushApiConsumer are provided by the Loki library

Design Choices

This Loki charm does not support (yet) the distributed deployment, only the standalone one.