Proposal: Provide official JSON Schema for ECS configuration(maybe other providers too ?)

[armistcxy]

What would you like to be added: A helper mechanism for validating and exploring YAML configuration fields, ideally with autocomplete and schema validation support.

Why is this needed:

• Context: When working with the ECS UpdateService API, configuration errors can be surprisingly hard to detect, especially when they involve incorrect field names that are silently ignored or not clearly validated

Example

deploymentConfiguration:
  deploymentStrategy: BLUE_GREEN # Wrong field name, it should be strategy

There is no immediate feedback, the API does not clearly indicate the mismatch which led to significant debugging time. At one point, it even caused confusion for me about whether UpdateService API supports changing deployment strategy at all

My implication for the above example is there should be a way to enforce and robust the way we write config.

Potential solution: Leverage YAML schema validation via JSON Schema, which is already supported by tools like the Red Hat YAML Language Server

How it works ?: By adding this line at the top of a YAML file:

# yaml-language-server: $schema=<path-to-json-schema-file>

How to generate JSON schema ?: By using package github.com/invopop/jsonschema, we can generate a JSON schema like this

	// Generate schema
	r := &jsonschema.Reflector{
		KeyNamer: func(s string) string {
			if len(s) == 0 {
				return s
			}
			return strings.ToLower(s[:1]) + s[1:] // lowercase the first character
		},
		RequiredFromJSONSchemaTags: true,
	}
	schema := r.Reflect(&ecs.CreateServiceInput{})
	output, _ := json.MarshalIndent(schema, "", "  ")

	file, err := os.Create("output.json")
	if err != nil {
		panic(err)
	}
	defer file.Close()

	file.Write(output)

Example result

Should we create and maintain something like this ? https://pipecd.dev/jsonschema/plugins/ecs/service.json

I would love to have discussion about this

[sridhar-panigrahi]

@armistcxy This is a really useful proposal. I've been looking at the ECS plugin config structs and they already have clean json tags and inline docs, so generating schema for PipeCD's own app.pipecd.yaml ECS section (i.e. ECSApplicationSpec) should be straightforward with invopop/jsonschema.

One thing I'm curious about is where the boundary should be — do we want schema coverage for just the app.pipecd.yaml ECS section, or also for the service/task definition files (servicedef.yaml, taskdef.json) which reference external AWS SDK types? The latter would be useful but the schema could get large and drift when the SDK updates.

Would love to hear from maintainers on whether this direction is something they'd want to merge, and if ECS-only is the right starting point or if it makes more sense to design it across plugins from the beginning.