Two same dependent resources in different namespaces

[AleksanderBrzozowski]

Hi, I wanted to ask what is the correct way to implement two dependent resources in different namespaces.

We want to create one dependent resource in primary namespace and a second dependent resource in istio-system namespace.

Furthermore, we use BulkDependentResource interface to be able to create 0 or 1 resources based on the config in primary resource.

here are code snippets:

@KubernetesDependent(namespaces = [Namespaces.ISTIO_SYSTEM])
class IstioSystemDependent :
    BulkDependentResource<EnvoyFilter, Api>,
    KubernetesDependentResource<EnvoyFilter, Api>(EnvoyFilter::class.java),
    Updater<EnvoyFilter, Api>,
    SecondaryToPrimaryMapper<EnvoyFilter> by Mappers.fromAnnotatons() {

    override fun desiredResources(primary: Api, context: Context<Api>): Map<String, EnvoyFilter> {
        if (condition()) {
            return emptyMap()
        }
        val envoyFilter = EnvoyFilterBuilder()
            .withMetadata(primary.toMetadata())
            .withSpec(primary.toSpec())
            .build()
        return mapOf(envoyFilter.metadata.name to envoyFilter)
    }

    override fun getSecondaryResources(primary: Api, context: Context<Api>): Map<String, EnvoyFilter> {
        val secondaryResources = context.getSecondaryResources(EnvoyFilter::class.java)
                         .filter { it.metadata.namespace == Namespaces.ISTIO_SYSTEM }
        return secondaryResources
            .associateBy { envoyFilter -> envoyFilter.metadata.name }
    }
    ...

And here is the second dependent resource, it is very similar, but it doesn't specify namespaces inside KubernetesDependent annotation, and the getSecondaryResources method is slightly different:

   override fun getSecondaryResources(primary: Api, context: Context<Api>): Map<String, EnvoyFilter> {
        val secondaryResources = context.getSecondaryResources(EnvoyFilter::class.java)
            .filter { it.metadata.namespace == primary.metadata.namespace }
        return secondaryResources
            .associateBy { envoyFilter -> envoyFilter.metadata.name }
    }

The question is if these filter methods are necessary here, or if there is another way to do this:

filter { it.metadata.namespace == Namespaces.ISTIO_SYSTEM }

filter { it.metadata.namespace == primary.metadata.namespace }

The problem is that these both resources use two event sources - EnvoyFilter for istio-system namespace and EnvoyFilter for primary resource namespace. As a result, this method: context.getSecondaryResources(EnvoyFilter::class.java) returns resources from both namespaces.

[csviri]

Hi @AleksanderBrzozowski

Furthermore, we use BulkDependentResource interface to be able to create 0 or 1 resources based on the config in primary resource.

This seems to me just a reconcilePrecondition for a standard dependent, no need for a bulk dependent.

The question is if these filter methods are necessary here, or if there is another way to do this:

Did you check this one in the docs:

https://javaoperatorsdk.io/docs/dependent-resources#multiple-dependent-resources-of-same-type

that part thould cover this use case as far I can see.

[AleksanderBrzozowski]

@csviri
Thanks for your response 🙂

This seems to me just a reconcilePrecondition for a standard dependent, no need for a bulk dependent.

I tried reconcilePrecondition and it works as expected. Our use case is that user provides the name of the resource that is going to be created, for example bar. However, it can be changed later from bar to foo, and in this case we need to delete old bar resource, and create new foo resource. I tried this scenario with reconcilePrecondition and I matched based on name, like:

override fun isMet(
    dependentResource: DependentResource<Dependent, Primary>,
    primary: Primary,
    context: Context<Primary>
): Boolean {
    val secondary = dependentResource.getSecondaryResource(primary, context)
        .orElse(null) ?: return true
    val expectedName = primary.toMetadata().name
    val actualName = secondary.metadata.name
    return expectedName == actualName
}

From what I checked, when there is bar dependent created, and we edit primary resource to change the name of dependent to foo, the workflow starts to reconcile and isMet returns false, thus dependent is deleted.

And after it is deleted, the workflow reconciles once again, and this time isMet returns true (because there is no dependent resource) and it creates new dependent with new name. Am I right? 🙂

Did you check this one in the docs:
https://javaoperatorsdk.io/docs/dependent-resources#multiple-dependent-resources-of-same-type
that part thould cover this use case as far I can see.

When I tried to use ResourceDiscriminator, I got an error:

java.lang.IllegalArgumentException: There are multiple EventSources registered for type io.fabric8.istio.api.networking.v1alpha3.EnvoyFilter

    override fun distinguish(
        resource: Class<EnvoyFilter>,
        primary: Api,
        context: Context<Primary>
    ): Optional<EnvoyFilter> {
        return context.getSecondaryResource(EnvoyFilter::class.java)
            .filter { it.metadata.namespace == primary.metadata.namespace }
    }

Do I need to use only one event source for both of these dependent resources? The method context.getSecondaryResource(EnvoyFilter::class.java, <event source name>) is deprecated.