PatchItemAsync does not support IfMatchEtag property

[KT-JuliaDias]

Hello,

I'm using Cosmos SDK in my application and using ETag optimistic locking for Upserts.
I'll need to use the PatchItemAsync method, however, it currently does not support the ETag property.

Do you have any plans to add this feature for patches?

Thank you, and looking forward to your response.

[FabianMeiswinkel]

An ETag means you have read the document already - why not use replace (with etag precondition)? Replace would have lower RU-charge than Patch and supports etag preconditions. PatchItem really is a convenience API for applications attempting to update documents wihtout reading the document before. If you absolutely want to do this you can use patch filter predicates - see

azure-cosmos-dotnet-v3/Microsoft.Azure.Cosmos/src/RequestOptions/PatchItemRequestOptions.cs

Lines 16 to 34 in 9bb0764

	/// <summary>
	/// Gets or sets condition to be checked before the patch operations in the Azure Cosmos DB service.
	/// </summary>
	/// <value>
	/// The condition to be checked before execution of operations.
	/// </value>
	/// <remarks>
	/// Condition can only be a from-clause of a sql statement.
	/// Creates a conditional SQL argument which is of format "FROM X where CONDITION",
	/// the condition has to be within the scope of the document which is supposed to be patched in the particular request.
	/// If the condition is satisfied the patch transaction will take place otherwise it will be returned with precondition failed.
	/// </remarks>
	/// <sample>
	/// PatchItemRequestOptions requestOptions = new PatchItemRequestOptions()
	/// {
	/// FilterPredicate = "from c where c.taskNum = 3"
	/// };
	/// </sample>
	public string FilterPredicate { get; set; }

[KT-JuliaDias]

makes sense! Thank you :D