Lookups

Lookup enables you to form components from an external source eg: an HTTP endpoint, kubernetes clusters or a database.

The response from the external sources are then "shaped" to a component using the display field.

The display field contains several scripting mechanism to transform any arbitrary data to a component.

For example this topology will create a root Ingress component with all the ingresses in a kubernetes cluster as its child components.

kubernetes-ingress-classes.yaml
apiVersion: canaries.flanksource.com/v1
kind: Topology
metadata:
  name: kubernetes-ingress-classes
  namespace: default
spec:
  schedule: '@every 30s'
  components:
    - name: Ingress
      type: Ingress
      icon: server
      lookup:
        configDB:
          - query: SELECT name FROM config_items WHERE type = 'Kubernetes::IngressClass'
            expr: |
              dyn(results).map(e, {
                'name': e.name,
                'type': "Ingress",
              }).toJSON()

Field	Description	Type
`catalog`	Lookup catalogs in configDB.	`[]Catalog`
`exec`	Lookup by running (bash/powershell) scripts.	`[]Exec`
`kubernetes`	Lookup kubernetes resources	`[]Kubernetes`
`http`	Lookup an HTTP endpoint.	`[]HTTP`
`mongodb`	Query records from a MongoDB database.	`[]MongoDB`
`sql`	Query records from a MSSQL database.	`[]SQL`
`redis`	Query records from a Redis server.	`[]Redis`
`prometheus`	Query metrics from Prometheus.	`[]Prometheus`

For Each

The forEach operation allows you to perform operations that you would apply to all the components crafted during the lookup phase.

In the example below, we can add a kubernetes check on each of the ingresses as follows

kubernetes-ingress-classes.yaml
apiVersion: canaries.flanksource.com/v1
kind: Topology
metadata:
  name: kubernetes-ingress-classes
  namespace: default
spec:
  schedule: '@every 30s'
  components:
    - name: Ingress
      type: Ingress
      icon: server
      lookup:
        configDB:
          - query: SELECT name FROM config_items WHERE type = 'Kubernetes::IngressClass'
            expr: |
              dyn(results).map(e, {
                'name': e.name,
                'type': "Ingress",
              }).toJSON()
      forEach:
        checks:
          - inline:
              kubernetes:
                - kind: Pod
                  ready: true
                  resource:
                    labelSelector: 'app.kubernetes.io/name=ingress-{{.component.name}}&app.kubernetes.io/component=controller'

Field	Description	Scheme
`components`	Create sub-components for each component	`[]Component`
`properties`	Create or lookup properties for each component	`[]Property`
`configs`	Link configuration items for each component	`[]ConfigSelector`
`checks`	Create or link health checks for each component	`[]CheckSelector`
`selectors`	Select existing components to be used as the child components.	`[]ResourceSelector`

Templating

All the fields in forEach are templatable. They receive the following context

Field	Description	Scheme
`component`	Component from the lookup	`[]Component`
`properties`	The component's properties	`map[string]any`

For Each​

Templating​

For Each

Templating