CosmosDBTrigger does not accept any valid StartFromTime value

[lostincomputer]

Description

CosmosDBTrigger does not accept any valid StartFromTime value and always fails with:

The listener for function 'Functions.Function1' was unable to start. Microsoft.Azure.WebJobs.Extensions.CosmosDB: The specified StartFromTime parameter is not in the correct format. Please use the ISO 8601 format with the UTC designator. For example: '2021-02-16T14:19:29Z'.

The exact same setup works in in-process model with Microsoft.Azure.WebJobs.Extensions.CosmosDB, but not in isolated worker model with Microsoft.Azure.Functions.Worker.Extensions.CosmosDB.

Steps to reproduce

Create an Isolated worker Azure function and reference Microsoft.Azure.Functions.Worker.Extensions.CosmosDB

[Function("Function1")]
public void Run([CosmosDBTrigger(
    databaseName: "databaseName",
    containerName: "containerName",
    Connection = "CosmosDbConnectionString",
    LeaseContainerName = "LeaseContainerName ",
    CreateLeaseContainerIfNotExists = true,
    StartFromTime = "2021-02-16T14:19:29Z" // Error is thrown even when I use the example value in the error message
    )] IReadOnlyList<Transaction> transactions)
{
}

[satvu]

Can you share which version you are using of the following:

• CosmosDB extension
• Worker
• Core-tools

Is this error reproducing locally or in production? I am unable to reproduce this error locally with the information you've provided - could you share a link to a GH repo of a minimal function app repro? Thanks!

[lostincomputer]

I'm reproducing the error locally. Here is a GH repo that reproduces the problem

CosmosDB extension version- 4.11.0
Worker version- 2.0.0
Core-tools version- 4.0.6610
Function Runtime version: 4.1036.1.23224

The bug might have something to do with the Window's region format setting. If my region format is "English (United States)", I get this error:

But if my region format is "English (New Zealand)", I get this:

This is the region format setting that I was talking about:

[satvu]

Thanks! Great find with the region format setting. I am able to repro locally - this thread will be updated as we continue investigating.

[satvu]

This is actually a host bug - in this line, the binding and properties are parsed using Newtonsoft.JSON, which has this known bug regarding ISO strings.

It is altering the string based on the local time settings, resulting in the errors above. Tracking the fix in the host at this issue: Azure/azure-functions-host#10732.