Cosmos DB: Enable merge support

sdk/data/azcosmos/CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## 0.3.5 (2023-05-09)
 
+### Features Added
+* Added support for accounts with [merge support](https://aka.ms/cosmosdbsdksupportformerge) enabled
+
 ### Bugs Fixed
 * Fixed unmarshalling error when using projections in value queries
 

sdk/data/azcosmos/cosmos_client.go

@@ -395,6 +395,7 @@ func (c *Client) createRequest(
 
 	req.Raw().Header.Set(headerXmsDate, time.Now().UTC().Format(http.TimeFormat))
 	req.Raw().Header.Set(headerXmsVersion, "2020-11-05")
+	req.Raw().Header.Set(cosmosHeaderSDKSupportedCapabilities, supportedCapabilitiesHeaderValue)
 
 	req.SetOperationValue(operationContext)
 

sdk/data/azcosmos/cosmos_client_test.go

@@ -258,6 +258,10 @@ func TestCreateRequest(t *testing.T) {
 		t.Errorf("Expected %v, but got %v", "2020-11-05", req.Raw().Header.Get(headerXmsVersion))
 	}
 
+	if req.Raw().Header.Get(cosmosHeaderSDKSupportedCapabilities) != supportedCapabilitiesHeaderValue {
+		t.Errorf("Expected %v, but got %v", supportedCapabilitiesHeaderValue, req.Raw().Header.Get(cosmosHeaderSDKSupportedCapabilities))
+	}
+
 	opValue := pipelineRequestOptions{}
 	if !req.OperationValue(&opValue) {
 		t.Error("Expected to find operation value")

sdk/data/azcosmos/cosmos_headers.go

@@ -33,6 +33,7 @@ const (
 	cosmosHeaderIsBatchRequest                     string = "x-ms-cosmos-is-batch-request"
 	cosmosHeaderIsBatchAtomic                      string = "x-ms-cosmos-batch-atomic"
 	cosmosHeaderIsBatchOrdered                     string = "x-ms-cosmos-batch-ordered"
+	cosmosHeaderSDKSupportedCapabilities           string = "x-ms-cosmos-sdk-supportedcapabilities"
 	headerXmsDate                                  string = "x-ms-date"
 	headerAuthorization                            string = "Authorization"
 	headerContentType                              string = "Content-Type"

sdk/data/azcosmos/sdk_capabilities.go

@@ -0,0 +1,21 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+package azcosmos
+
+import "strconv"
+
+type supportedCapabilities uint64
+
+const (
+	supportedCapabilitiesNone           supportedCapabilities = 0
+	supportedCapabilitiesPartitionMerge supportedCapabilities = 1 << 0
+)
+
+var supportedCapabilitiesHeaderValue = supportedCapabilitiesAsString()
+
+func supportedCapabilitiesAsString() string {
+	supported := supportedCapabilitiesNone
+	supported |= supportedCapabilitiesPartitionMerge
+	return strconv.FormatUint(uint64(supported), 10)
+}