Helmsnap

About

Helmsnap is a tool for generating and checking helm chart snapshots. Example:

Generate snapshots (uses helm template under the hood):

helmsnap generate -c helm/mychart -s helm/snapshots -v helm/values/production.yaml

Generate snapshots in some temp directory and check (diff) them against existing snapshots in helm/snapshots directory:

helmsnap check -c helm/mychart -s helm/snapshots -v helm/values/production.yaml

Get the full description of possible arguments:

helmsnap --help

The typical usage flow:

1. You generate some snapshots using helmsnap generate command and check them into your git repo.
2. You add helmsnap check command to your CI (or run it manually on every commit).
3. In case snapshots differ, you should carefully check the updates and either fix your chart or update the snapshots using helmsnap generate.

This tool can also be useful when you are developing a new chart or updating an existing one: you can generate snapshots and see what is rendered without need to deploy the chart in your cluster.

Features

Helm dependency management

Helmsnap will automically rebuild your chart dependencies on every snapshot generation or check. In case your dependency is using url to some local helm repo and you don't have a proper repo added, it will add it automically which is useful in CI. It also will detect local dependencies (those that start with file://) and rebuild their dependencies as well.

Timestamp replacement

Helmsnap will automically replace all occurencies of patterns that look like timestamps (format like 2022-01-01 00:00:00.000) in your templates. This is useful in case you have some annotations like releaseTime that would break your snapshots checks otherwise.

Installation

Just install a gem and use the provided helmsnap binary.

gem install helmsnap

Alaternatively, you can use a Docker image with Ruby, helm and helmsnap gem preinstalled. This is useful for CIs or if you don't want to install Ruby locally.

CI example

Example job for Gitlab CI:

check-snapshots:
  stage: test
  image: ghcr.io/tycooon/helmsnap:latest
  script: helmsnap check -c helm/mychart -s helm/snapshots -v helm/values/production.yaml

Contributing

Bug reports and pull requests are welcome.

License

The gem is available as open source under the terms of the MIT License.