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Server Cluster Shim

Overview

The ServerClusterShim provides a way to adapt legacy (codegen/Ember-based) server cluster implementations to the new ServerClusterInterface. It acts as an intermediary layer, translating between the new interface methods and legacy emberAf... calls. This allows developers to isolate the dependency on code generation to the cluster layer, instead of leaking it into the data model provider layer.

This ServerClusterShim enables us to develop a new Data Model Provider (fully code-driven) that doesn‘t depend on codegen/Ember and can be tested against real clusters (while the clusters themselves are not all migrated to fully code-driven yet). This is meant to be a temporary option, until all cluster implementations have been migrated to implement the new interface. This is an effort that’s currently in progress in the SDK.

Usage

To use the ServerClusterShim, you need to:

• Have a ZAP file with all of the legacy clusters configured.
• Instantiate a ServerClusterShim providing the endpoint and cluster ID into the constructor.
  • You can either instantiate one ServerClusterShim for multiple endpoint/cluster ID pairs or one for each cluster.
• Call ServerClusterShim::Startup to initialize the cluster with a ServerClusterContext.
• Interact with the cluster by calling any of the ServerClusterInterface methods such as:
  • ReadAttribute, WriteAttribute, InvokeCommand, etc.

See some other examples in TestServerClusterShim.cpp.

// Instantiate a `ServerClusterShim`
ServerClusterShim cluster({ { endpointId, clusterId } });

// Startup with a ServerClusterContext
ServerClusterContext clusterContext{.provider = &provider, .storage = nullptr, .interactionContext = &imContext};
cluster.Startup(&clusterContext);

// Read Attributes (for example, feature map)
ReadOperation readOperation(endpointId, clusterId, Attributes::FeatureMap::Id);
std::unique_ptr<AttributeValueEncoder> encoder = readOperation.StartEncoding();

ASSERT_EQ(cluster.ReadAttribute(readOperation.GetRequest(), *encoder), CHIP_NO_ERROR);
ASSERT_EQ(readOperation.FinishEncoding(), CHIP_NO_ERROR);

// Validate after read
std::vector<DecodedAttributeData> attribute_data;
ASSERT_EQ(readOperation.GetEncodedIBs().Decode(attribute_data), CHIP_NO_ERROR);