crd-modifier

crd-modifier

What is crd-modifier?

crd-modifier is a command-line tool designed for post-processing Custom Resource Definition (CRD) files for TiDB Operator. Its primary function is to remove certain required constraints within the overlay field's schema in the CRDs. This provides greater flexibility when customizing Pod templates, helping to avoid unnecessary validation errors.

How it Works

The tool scans a specified directory (defaulting to manifests/crd) for all CRD files with .yaml extension. For each CRD file, it inspects its OpenAPI v3 schema to determine the CRD type and applies modifications accordingly:

• Group-type CRDs: If an overlay field is detected at the path spec.template.spec.overlay, the tool identifies it as a group-type CRD (e.g., PDGroup, TiKVGroup). It then proceeds to remove the required constraint from the pod sub-field within that overlay.

• Instance-type CRDs: If an overlay field is detected at the path spec.overlay.pod, the tool identifies it as an instance-type CRD (e.g., PD, TiKV). Similarly, it removes the required constraint from the pod sub-field within that overlay.

• Special CRDs: For CRDs with nested overlay structures (like TiBRGC), where overlays are located at spec.overlay.pods[].overlay, the tool automatically detects and processes these special cases.

This schema-based detection mechanism ensures robust forward compatibility. As long as new CRDs follow the established overlay structure patterns, they can be processed automatically without requiring code changes. The tool gracefully handles CRDs that don't have overlay fields by skipping them.

How to Use

You can run the tool by executing the main.go file with go run. Use the --dir flag to specify the directory containing the CRDs.

go run cmd/crd-modifier/main.go --dir <your-crd-manifests-path>

If the --dir flag is omitted, it will default to the manifests/crd directory in the project root.

Output

The tool provides detailed logging to show which CRDs are being processed and what type of overlay structure was detected. This helps with debugging and understanding what modifications were applied.