Dependencies

This section of the guide covers best practices for dependencies declared in Chart.yaml.

Versions

Where possible, use version ranges instead of pinning to an exact version. The suggested default is to use a patch-level version match:

version: ~1.2.3

This will match version 1.2.3 and any patches to that release. In other words, ~1.2.3 is equivalent to >= 1.2.3, < 1.3.0

For the complete version matching syntax, please see the semver documentation.

Repository URLs

Where possible, use https:// repository URLs, followed by http:// URLs.

If the repository has been added to the repository index file, the repository name can be used as an alias of URL. Use alias: or @ followed by repository names.

File URLs (file://...) are considered a "special case" for charts that are assembled by a fixed deployment pipeline. Charts that use file:// are not allowed in the official Helm repository.

Experimental support for Charts hosted on OCI registries

If you have enabled experimental OCI support, you can specify an OCI reference (oci://registry/group/image:tag) for the repository URL.

When specifying an OCI reference, you may omit the version argument if your repository URL contains an image tag (oci://nginx:1.10). If you do not specify a tag on the URL, the version will be used as the tag. This means that OCI URLs do not support SemVer constraints, only tagged versions are supported.

If you specify both a tag and a version, the tag takes precedence and the version is ignored.

Conditions and Tags

Conditions or tags should be added to any dependencies that are optional.

The preferred form of a condition is:

condition: somechart.enabled

Where somechart is the chart name of the dependency.

When multiple subcharts (dependencies) together provide an optional or swappable feature, those charts should share the same tags.

For example, if both nginx and memcached together provided performance optimizations for the main app in the chart, and were required to both be present when that feature is enabled, then they might both have a tags section like this:

tags:
  - webaccelerator

This allows a user to turn that feature on and off with one tag.