Owner: Architect:

Francesco Ilario

Story (Required)

As a Service Administrator,
I would like to compose data extracted from Resources
so that I can create Composite data in RegisteredServices

Background (Required)

Given the following CRD

apiVersion: mypsql.io/v1alpha1
kind: MyPostgres
spec: 
  port: 5432
  host: my-psql.my-cloud-provider.dev

There is actually no way of having a field in the generated RegisteredService that uses the port and host to create a new field url: psql://my-psql.my-cloud-provider.dev:5432

See epic for arch document link.

Glossary

See glossary in architecture document

Out of scope

NA

In Scope

• ServiceClass CRD changes
• Using GoTemplate in ServiceClass data extraction

Approach(Required)

An example of ServiceClass as of now is the following

apiVersion: primaza.io/v1alpha1
kind: ServiceClass
metadata: 
    name: myserviceclass
    namespace: services
spec: 
    resource: 
        apiVersion: stable.example.com/v1
        kind: Backend
        serviceEndpointDefinitionMappings: 
            resourceFields: 
            - name: host
              jsonPath: .spec.host
              secret: false
    serviceClassIdentity: 
      - name: type
        value: backend

We can update the resourceFields spec to support the following specifications

resourceFields: 
  - name: url
    secret: false
    value: 
      template: "psql://{{.spec.host}}:{{.spec.port}}"
  - name: host
    secret: false
    value: 
      jsonPath: .spec.host

The value field should have the kubebuilder constraints on mix and max properties set to 1, i.e.:

// +kubebuilder:validation:MaxProperties:=1
// +kubebuilder:validation:MinProperties:=1

Using GoTemplates directly on the Service data structure or unstructured.Unstructured may result in inconsistent fields naming for the Primaza user.
For mitigating this issue, we can unmarshal the JSON representation of the Service to a generic Go map, like in the following (not tested) snippet:

t := template.Must(template.New("").Parse(templ))

m := map[string]interface{}
if err := json.Unmarshal([]byte(jsondata), &m); err != nil {
    return err
}

var buf bytes.Buffer
w := bufio.NewWriter(&b)
if err := t.Execute(w, m); err != nil {
    return err
}

Demo requirements(Required)

NA

Dependencies

NA

Edge Case

NA

BDD Tests

You can find BDD Test specification for this story in the "Testing Instruction" Field Tab or in the GitHub Issue linked to this story.
Click here for all BDD Tests Issues.

Acceptance Criteria

• Development
  ServiceClass CRD Updates
  Extract data using Go Template on Service JSON representation

• QE
  There are test cases for data extracted using template field

• Docs
  There is a section in our ServiceClass doc dedicated to explaining how to extract data using the template approach
  Update architecture document with any changes while implementing

INVEST Checklist

Dependencies identified
Blockers noted and expected delivery timelines set
Design is implementable
Acceptance criteria agreed upon
Story estimated

Legend

Unknown
Verified
Unsatisfied