Expose failed API requrests through event log

[Rohlik]

Describe the bug
When provisioning invalid GrafanaDatasource, you will encounter an error like the one below, which isn't helpful because it doesn't give a reason. I spent quite a bit of time debugging it and figured out what was wrong 😥.
In the end, I was able to find out that the root cause was missing access: proxy parameter within the definition, even though official documentation doesn't explicitly mention it in the "minimal working example": https://grafana.com/docs/plugins/yesoreyeram-infinity-datasource/latest/setup/provisioning/#basic-provisioning.

Moreover, this plugin can generate its provisioning definition within its settings, and the generated config doesn't even include an access property 😕:

It's only partly related, but there is also a JSON validation scheme for this GrafanaDatasource CR at https://raw.githubusercontent.com/datreeio/CRDs-catalog/main/grafana.integreatly.org/grafanadatasource_v1beta1.json#', but even there, access is not set as required.

Error log:

{"level":"error","ts":"2025-09-05T07:31:06Z","msg":"Reconciler error","controller":"grafanadatasource","controllerGroup":"grafana.integreatly.org","controllerKind":"GrafanaDatasource","GrafanaDatasource":{"name":"infinity-datasource","namespace":"monitoring"},"namespace":"monitoring","name":"infinity-datasource","reconcileID":"0b292f41-360e-4c9d-bdb0-194e4f5ea6e4","error":"failed to apply to all instances: map[monitoring/grafana:[POST /datasources] addDataSource (status 400): {}]","stacktrace":"sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller[...]).reconcileHandler\n\tsigs.k8s.io/controller-runtime@v0.21.0/pkg/internal/controller/controller.go:353\nsigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller[...]).processNextWorkItem\n\tsigs.k8s.io/controller-runtime@v0.21.0/pkg/internal/controller/controller.go:300\nsigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller[...]).Start.func2.1\n\tsigs.k8s.io/controller-runtime@v0.21.0/pkg/internal/controller/controller.go:202"}

Version
v5.19.4

To Reproduce
Steps to reproduce the behavior:

1. Apply this CR in your K8s

apiVersion: grafana.integreatly.org/v1beta1
kind: GrafanaDatasource
metadata:
  name: infinity-datasource
spec:
  resyncPeriod: 30s
  instanceSelector:
    matchLabels:
      grafana_dashboard: "true"
  datasource:
    name: Infinity-Datasource
    type: yesoreyeram-infinity-datasource
    uid: INFINITY

2. Datasource is not provisioned
3. Check the logs of grafana-operator to see the error

Expected behavior
Provide a clear explanation within the logs of the issue to help resolve the error more quickly. Something like:

Datasource needs to have access property defined.

Suspect component/Location where the bug might be occurring
unknown

Runtime (please complete the following information):

• OS: Linux
• Grafana Operator Version v5.19.4
• Environment: EKS
• Deployment type: Helm

Additional context
Add any other context about the problem here.

[theSuess]

Thanks for raising the issue! This is a bit tricky as the validation happens on the data source side, so we can't define our own errors. We'll discuss this today and look into how to best expose those errors

[theSuess]

We'll investigate if we can get more detailed information from the API and expose it through the event log. I've updated the issue title accordingly