Move datasource/extractor validations to datalayer runtime. by elevran · Pull Request #2357 · kubernetes-sigs/gateway-api-inference-extension

elevran · 2026-02-17T11:05:50Z

What type of PR is this?
/kind cleanup

What this PR does / why we need it:
Following up on comments in #2228:

Extractors declare their expected input type (unchanged)
DataSource declare their output type and expected Extractor type (new)
Compatibility validation utility functions and tests in plugins/datalayer/source (new, moved)
Datalayer WithConfig() validates compatbility before calling AddExtractor (new)
DataSource can optionaly implement validating interface method to perform specific compatibility checks (new)
Current DataSource checks on AddExtractor and their tests are not changed to minimize the code changes.

Notes (relating to comments on #2228)

The metric names used in Produces() and other Plugin's Consumes() are already in the metrics Extractor under the framework.
Morphing Metrics (or MetadataState) as generic Attributes is not done (low impact, large changeset).

Which issue(s) this PR fixes:
Fixes #2234
Replaces #2336

Does this PR introduce a user-facing change?:

NONE

- Extractors declare their expected input type (unchanged) - DataSource declare their output type and expected Extractor type (new) - Compatibility validation utility functions and tests in plugins/datalayer/source (new, moved) - Datalayer WithConfig() validates compatbility before calling AddExtractor (new) - DataSource can optionaly implement validating interface method to perform specific compatibility checks (new) - Current DataSource checks on AddExtractor and their tests are not changed to minimize the code changes. Signed-off-by: Etai Lev Ran <elevran@gmail.com>

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k8s-ci-robot · 2026-02-17T11:05:57Z

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: elevran
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k8s-ci-robot · 2026-02-17T11:25:05Z

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ahg-g · 2026-02-17T13:17:05Z

pkg/epp/framework/plugins/datalayer/source/validate.go

+
+// ValidateInputTypeCompatible checks if the extractor's expected input type is
+// compatible with the DataSource's output type.
+func ValidateInputTypeCompatible(dataSourceOutput, extractorInput reflect.Type) error {


do we expect that those validation checks will be run by anyone other than the runtime? Do we expect the plugins to execute them for example or llm-d main? If not, then this belongs more in the runtime pkg.

if by runtime you mean pkg/epp/datalayer then it was moved here based on previous feedback (avoid framework from importing packages outside).
I prefer to leave it here to allow framework/*/source implementations to call these if needed.
datalayer.WithConfig() will only call these when working with configuration files (e.g., not in tests or when the datalayer is configured directly - not in code) so we leave it up open for failures in some cases.

if by runtime you mean pkg/epp/datalayer then it was moved here based on previous feedback (avoid framework from importing packages outside).

Yes, but the main question was: do we expect any logic other than runtime to call it in the first place? if not, why make it part of the interface?

The initial implementation was expecting the plugins to invoke it, but then we discussed that this validation logic should be executed by the runtime (which processes the config and instantiates the plugins), the plugins themselves are not supposed to call it, and so this logic can live in the epp/datalayer as private functions.

See comments below on calling on addExtractor vs calling on ExtractNotification/Extract.
Let me know which approach you prefer

leave in framework and validate on adding an extractor (withConfig calling it is redundant in that case); or

validate on every extraction

Will change to whichever is preferred.

I think we only need to validate once, the runtime does that before calling AddExtractor (which I think we should remove as well, see the other comment)

ahg-g · 2026-02-17T13:23:19Z

pkg/epp/framework/plugins/datalayer/source/http/datasource.go

 // the data source output type.
 func (dataSrc *HTTPDataSource) AddExtractor(extractor fwkdl.Extractor) error {
-	if err := datalayer.ValidateExtractorType(dataSrc.outputType, extractor.ExpectedInputType()); err != nil {
+	if err := source.ValidateInputTypeCompatible(dataSrc.OutputType(), extractor.ExpectedInputType()); err != nil {


Why do we call it here still? the datalayer runtime calls it already

when dispatching to an extractor we can trust it to be of the right type (it was validated) or we need to verify the interface at runtime and fail if incompatible.

I am not following, the epp/datalayer already calls this before it runs AddExtractor, why does the plugin itself has to do it again? The plugin already defined what it produces and what it expects, the runtime is the entity responsible for enforcement when setting things up.

I also think the source should not expose an AddExtractor interface, the runtime is the one that should maintain which extractors are configured for which source and invoke them, the runtime

maintains the source <-> extractor mapping

runs the iteration that we currently force all plugins to execute inside the Collect function to invoke Extract on each extractor. To enable this, the Collect interface changes to return the data, that the datalayer runtime pass that to the extract call when it iterates over the extractors.

The idea is to move all mechanical logic to be done by the runtime (validations, maintaining source<->extractor mapping as per the config, invoking the extractors on each collect etc.), the plugins are focused on implementing the plugin specific logic only.

ahg-g · 2026-02-17T13:25:52Z

pkg/epp/framework/plugins/datalayer/source/notifications/k8s_datasource.go

-		return fmt.Errorf("extractor %s does not implement NotificationExtractor", ext.TypedName())
+	extractorType := reflect.TypeOf(ext)
+	expectedType := reflect.TypeOf((*fwkdl.NotificationExtractor)(nil)).Elem()
+	if err := source.ValidateExtractorCompatible(extractorType, expectedType); err != nil {


Why do we have to call it here still? The validation is done by the runtime.

ditto.
Do we validate once on adding the extractor (regardless of if by config or not) or do we validate on every call to Extarct (and if there are multiple extractors, I presume we would want log a message and continue, but not spam the log file...?)

k8s-ci-robot added the kind/cleanup Categorizes issue or PR as related to cleaning up code, process, or technical debt. label Feb 17, 2026

k8s-ci-robot requested review from liu-cong and robscott February 17, 2026 11:05

k8s-ci-robot added the cncf-cla: yes Indicates the PR's author has signed the CNCF CLA. label Feb 17, 2026

k8s-ci-robot added the size/L Denotes a PR that changes 100-499 lines, ignoring generated files. label Feb 17, 2026

elevran closed this Feb 17, 2026

elevran reopened this Feb 17, 2026

elevran mentioned this pull request Feb 17, 2026

Moved DataSource and Extractor type validation to framework #2336

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ahg-g reviewed Feb 17, 2026

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netlify bot commented Feb 17, 2026 •

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