Implementation:Datahub project Datahub VersionAwarePatchTransformer

Knowledge Sources	Datahub_project_Datahub
Domains	Java_SDK, Metadata_Management
Last Updated	2026-02-10 00:00 GMT

Overview

Description

VersionAwarePatchTransformer is the primary implementation of the PatchTransformer interface. It transforms patch MetadataChangeProposal (MCP) objects based on server version compatibility, handling known version-specific issues with patches on DataHub servers.

The transformer addresses two categories of compatibility:

• Always-transformed aspects: mlModelProperties patches are not supported on any current server version and are always transformed to full aspect replacements with optimistic locking retry functions.
• Version-gated aspects: Patches for editableContainerProperties, editableDatasetProperties, and editableMLModelGroupProperties are transformed only for DataHub Core servers at version <= v1.3.0.

Version thresholds:

Aspect	DataHub Core	DataHub Cloud
mlModelProperties	Always transform	Always transform
editableContainerProperties	> v1.3.0	TBD
editableDatasetProperties	> v1.3.0	TBD
editableMLModelGroupProperties	> v1.3.0	TBD

The class uses Lombok @RequiredArgsConstructor and @Slf4j annotations.

Usage

This transformer is instantiated with an EntityClient reference (needed for read-modify-write operations) and is invoked automatically during entity upsert operations. When server config is unavailable, patches are passed through unchanged with a warning.

Code Reference

Source Location

metadata-integration/java/datahub-client/src/main/java/datahub/client/v2/patch/VersionAwarePatchTransformer.java

Signature

@Slf4j
@RequiredArgsConstructor
public class VersionAwarePatchTransformer implements PatchTransformer {

    @Nonnull
    private final EntityClient entityClient;

    @Override
    @Nonnull
    public List<TransformResult> transform(
        @Nonnull List<MetadataChangeProposal> patches,
        @Nullable ServerConfig serverConfig) throws Exception

    private boolean needsPatchTransformation(@Nonnull ServerConfig serverConfig)
}

Import

import datahub.client.v2.patch.VersionAwarePatchTransformer;

I/O Contract

Inputs

Parameter	Type	Description
constructor entityClient	EntityClient	Client used for read-modify-write during transformation
transform patches	List<MetadataChangeProposal>	Original patch MCPs to transform
transform serverConfig	ServerConfig (nullable)	Server configuration for version checking

Outputs

Method	Return Type	Description
transform	List<TransformResult>	Transformed MCPs with optional retry functions

Transformation behavior by aspect:

Aspect Name	Server Config Null	Server Compatible	Server Incompatible
mlModelProperties	Pass-through (no retry)	Full replacement + retry	Full replacement + retry
editableContainerProperties	Pass-through	Pass-through	Full replacement (no retry)
editableDatasetProperties	Pass-through	Pass-through	Full replacement (no retry)
editableMLModelGroupProperties	Pass-through	Pass-through	Full replacement (no retry)
Other aspects	Pass-through	Pass-through	Pass-through

Exceptions:

• Exception - if transformation fails (e.g., aspect fetch failure)
• RuntimeException - wrapping retry failures for mlModelProperties

Usage Examples

// VersionAwarePatchTransformer is typically used internally by EntityClient.
// It is instantiated with the EntityClient reference:

EntityClient entityClient = new EntityClient(config);
VersionAwarePatchTransformer transformer =
    new VersionAwarePatchTransformer(entityClient);

// Transform patches based on server capabilities
List<MetadataChangeProposal> patches = collectPatches();
ServerConfig serverConfig = entityClient.getServerConfig();
List<TransformResult> results = transformer.transform(patches, serverConfig);

// Each result contains the MCP and optional retry function
for (TransformResult result : results) {
    MetadataChangeProposal mcp = result.getMcp();
    // result.getRetryFn() may be non-null for optimistic locking
}

Related Pages

• Implementation:Datahub_project_Datahub_PatchTransformer - Interface this class implements
• Implementation:Datahub_project_Datahub_AspectWithMetadata - Provides version info for optimistic locking
• Implementation:Datahub_project_Datahub_HasOwners_Mixin - Generates ownership patches consumed by this transformer
• Implementation:Datahub_project_Datahub_HasGlossaryTerms_Mixin - Generates glossary term patches consumed by this transformer