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Helm Resource

Author: Nick Santos

Use Helm to deploy services to a cluster.

Prefer this extension to helm_remote for new projects.

Requirements:

  • Tilt v0.23.4+
  • Helm 3
  • Python 3

Functions

helm_resource


def helm_resource(
    name,
    chart,
    deps=[],
    release_name='',
    namespace=None,
    image_deps=None,
    image_keys=None,
    flags=None,
    image_selector='',
    container_selector='',
    live_update=None,
    resource_deps=None,
    labels=None,
    port_forwards=[],
    auto_init=True,
    pod_readiness='',
    update_dependencies: False
    links=[]):
  ...

Installs a helm chart to a cluster.

Arguments:

name: The name of the resource in the Tilt UI.

chart: A reference to a chart. Uses the same syntax as helm install [release-name] [chart]. May be a local path, a local tarball, or a repo/name reference.

deps: A list of file dependencies that should trigger a deployment.

release_name: The name of the release. If not specified, defaults to the Tilt UI resource name.

namespace: Install into the specified namespace.

image_deps: A list of images built by Tilt to inject into the chart. If Tilt doesn't know how to build one of these images, this will be an error.

image_keys: A list of specifications for how to inject images into the chart. Must be the same length as image_deps. Examples of accepted values:

  • 'image': A chart that accepts a single tagged image reference, passed as a string.

  • ('image.repository', 'image.tag'): A chart that accepts an image as a separate repository and tag, passed as a 2-element tuple. This is how charts created with helm create are structured.

  • ('image.registry', 'image.repository', 'image.tag'): A chart that accepts an image as a 'registry', 'repository' and a 'tag', passed as a 3-element tuple. This is another common pattern used by many charts.

  • [('image.repository', 'image.tag'), ('initImage.repository', 'initImage.tag')]: A chart that uses the same image in two different values. Passed as a list.

flags: Additional flags to pass to helm install. For example:

  • Pass values as flags=['--set=key=value'].

  • Pass a version as flags=['--version=1.0.0'].

  • Pass a values file as flags=['--values=./path/to/values.yaml'].

uninstall_flags: Additional flags to pass to helm uninstall.

image_selector: Image reference to determine containers eligible for Live Update. Only applicable if there are no images in image_deps.

container_selector: Container reference to determine containers eligible for Live Update. Only applicable if there are no images in image_deps.

live_update: Live Update steps for images not built by Tilt. Only applicable if there are no images in image_deps.

resource_deps: Tilt resources to depend on. Useful for adding a dependency on a helm repo install.

labels: Labels for categorizing the resource.

port_forwards: Host port to connect to the pod. Takes the same form as port_forwards in the k8s_resource command.

auto_init: Whether this resource runs on tilt up. Defaults to True. For more info, see the Manual Update Control docs.

pod_readiness: Possible values: 'ignore', 'wait'. Controls whether Tilt waits for pods to be ready before the resource is considered healthy (and dependencies can start building). By default, Tilt will wait for pods to be ready if it thinks a resource has pods.

update_dependenices: Runs helm dependency update before installing the chart.

links: One or more links to be associated with this resource in the UI. For more info, see Accessing Resource Endpoints.

helm_repo

def helm_repo(
    name,
    url,
    username='',
    password='',
    **kwargs):
  ...

Installs a helm repo on tilt up.

Arguments:

name: The name of the helm repo.

url: The url of the helm repo.

username: The username for authenticating (if the helm repo is private).

password: The password for authenticating (if the helm repo is private).

**kwargs: Arguments to pass to the underlying resource like labels (for organization).

Examples

See the test directory for a simple example.

Implementation Notes

Previous Approaches

In a Tilt environment, there are a few different approaches to installing a Helm chart.

  • You can use local() or local_resource() to invoke helm upgrade --install as a local shell script. This works and is easy to get started. But Tilt has no way to "see" what the shell scripts are installing, or monitoring them after they're done.

  • Tilt offers a built-in helm() command that converts local Helm charts into Kubernetes YAML. k8s_yaml(helm('./path/to/chart')) registers the resources so that Tilt can deploy them. This works well for simple charts. Helm 3 has lots of great features for customizing the install process (e.g., waiting on CRD installation) that this approach misses out on.

  • Bob Jackman wrote a helm_remote Tilt extension. helm_remote downloaded a remote chart, unpacked it on local disk, converted it to Kubernetes YAML, then registered that YAML with Tilt. Because people often used this to install Kuberentes CRDs and operators, helm_remote would register CRDs as a separate resource and use Tilt's dependency-management to customize the install process.

You can read more in the Tilt Helm Docs

How this Approach is Different

Tilt now has a k8s_custom_deploy built-in that lets you use arbitrary shell scripts to deploy resources, without losing Tilt's ability to monitor health, stream logs, and sync live-updates.

helm_resource is a k8s_custom_deploy wrapper that deploys with Helm. More importantly, it incorporates a lot of what the Kubernetes community has learned about how to group packages of YAML for installation. You can see this in the evolution from Helm 2 to Helm 3.

Future Work

Currently, helm_repo doesn't try to keep the repo up to date.

In the past, we've found it difficult to efficiently manage this information from the Tiltfile. Ideally, tilt up against an existing environment should be well-cached and fast. But maybe there are ways to do this with UIButtons that manually trigger a repo update.

Acknowledgements

Thanks to Bob Jackman for the original helm_remote and a lot of the early experiments with Helm charts.

This extension is based an an early POC Milas Bowman wrote for k8s_custom_deploy.