feat(helm): AS-706 helm values schema

[afoley587]

Rationale

A helm values schema allows us to validate/verify a user's values.yaml file entries before installing. It allows us to then display helpful messages about type mismatches / expected values / etc.

This, hopefully, makes installations easier for customers and allows us to provide a smoother experience.

Changes

1. Adds a new pre-commit hook for helm-schema

2. Adds a new makefile target for installing helm plugins

3. Updates pre-commit workflow to install helm-schema for the new pre-commit hook

4. Creates the new values.schema.json file with the following settings:

   ---
   # https://github.com/losisin/helm-values-schema-json/tree/main
   
   # https://json-schema.org/draft/2020-12
   draft: 2020
   
   indent: 4
   
   output: helm/fiftyone-teams-app/values.schema.json
   
   # Allow additional properties such as env vars
   # and additional maps
   noAdditionalProperties: false
   
   useHelmDocs: true
   
   values:
     - helm/fiftyone-teams-app/values.yaml

5. Also disables a new markdown lint finding:

   # MD059/descriptive-link-text Link text should be descriptive
   # This rule marks things like:
   # `Example nginx configurations can be found [here](../)`
   # as errors.
   # The context comes before the link so this seems
   # like a fair rule to disable.
   MD059: false

Checklist

• This PR maintains parity between Docker Compose and Helm

Testing

Test 1: Inserting a map where an array is expected

Using this test, we should throw an error because topologySpreadConstraints should be a list

apiSettings:
  topologySpreadConstraints:
      maxSkew: 
        topologyKey: 
        whenUnsatisfiable: 
        labelSelector:
          matchLabels:
            app.kubernetes.io/name: teams-api-foo
            app.kubernetes.io/instance: dev-fiftyone-ai

Running the below shows it does!

 % helm install --dry-run dev-fiftyone-ai ./helm/fiftyone-teams-app --values ../cloud-build-and-deploy/helm-configs/dev-values.yaml --namespace dev-fiftyone-ai
coalesce.go:301: warning: destination for fiftyone-teams-app.apiSettings.topologySpreadConstraints is a table. Ignoring non-table value ([])
Error: INSTALLATION FAILED: values don't meet the specifications of the schema(s) in the following chart(s):
fiftyone-teams-app:
- apiSettings.topologySpreadConstraints: Invalid type. Expected: array, given: object

Test 2: Inserting a string where an int is expected

Using this test, we should throw an error because podDisruptionBudget.minAvailable" should be an int`

casSettings:
  podDisruptionBudget:
    enabled: true
    minAvailable: "1"

Running the below shows it does!

 % helm install --dry-run dev-fiftyone-ai ./helm/fiftyone-teams-app --values ../cloud-build-and-deploy/helm-configs/dev-values.yaml --namespace dev-fiftyone-ai
Error: INSTALLATION FAILED: values don't meet the specifications of the schema(s) in the following chart(s):
fiftyone-teams-app:
- casSettings.podDisruptionBudget.minAvailable: Invalid type. Expected: integer, given: string

Test 3: Making sure additional keys are allowed

Using this test, we should not throw an error

casSettings:
  env:
    CAS_DATABASE_NAME: dev-cas
    CAS_DEFAULT_USER_ROLE: ADMIN
    FIFTYONE_APP_BANNER_COLOR: "orange"
    FIFTYONE_APP_BANNER_TEXT_COLOR: "purple"
    FIFTYONE_APP_BANNER_TEXT: "You are currently viewing the Dev Deployment"
    THIS_IS_SPARTA: yay <---- additional key, not in schema

Running the below shows it does!

 % helm install --dry-run dev-fiftyone-ai ./helm/fiftyone-teams-app --values ../cloud-build-and-deploy/helm-configs/dev-values.yaml --namespace dev-fiftyone-ai

[kevin-dimichel]

Nice!

[findtopher]

It'd be nice to see some documentation about how a customer might use this; right now it just looks like another thing that will frustrate me when I put a percentage in where an integer was tested....

[afoley587]

It'd be nice to see some documentation about how a customer might use this; right now it just looks like another thing that will frustrate me when I put a percentage in where an integer was tested....

Customers won't use this directly. When they run a helm install -f some-values.yaml, helm will look at their settings in the some-values.yaml file and compare the types to the schema. If there is a type mismatch (i.e. they're using a string instead of an int), helm will tell them the error:

Error: INSTALLATION FAILED: values don't meet the specifications of the schema(s) in the following chart(s):
fiftyone-teams-app:
- casSettings.podDisruptionBudget.minAvailable: Invalid type. Expected: integer, given: string

But we can talk offline to discuss how to make sure no one has a negative experience!

[findtopher]

It's unfortunate that this can't be used ahead of time to validate the config file... oh well!

[afoley587]

Closing for now. I am going to use a new tool which gives some more freedom over the union of types and will need to retest.