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I know how to bind queries directly to an Azure Function and use Cosmos DB triggers in functions.

However, I'm looking for direction around using DocumentClient (Nuget package Microsoft.Azure.Cosmos) directly.

1. There's documentation that explains how to reuse a static client instance between executions.
2. It is also possible to get a DocumentClient instance as a binding by adding [DocumentDB("test", "test", ConnectionStringSetting = "CosmosDB")] DocumentClient client to the function's parameters.
3. Finally, it is possible to create a DocumentClient instance in the function's body: var client = new DocumentClient(...).

I do not find a clear recommendation when to use what approach except that number 3 never is a good option because of performance, memory usage and connection limits. Also, I understand that using a static instance has advantages.

Questions

• Azure functions have a connection limit (discussed here). Does this also apply when using approach 2 (bind to client)?
• What are the pros and cons of using approach 2 (binding) versus 1 (static)?
• What's the advantage of binding to a SQL query compared to binding to a DocumentClient and creating the query in the function's body?

I want to use output queue in my azure function. I get an example code from: https://docs.microsoft.com/en-us/sandbox/functions-recipes/queue-storage

With recent changes to the Azure Function App version 2 in Sept 2018, my function app code was refactored. However, it seems that:

• LogTrace() messages no longer show in the console window (and I suspect Application Insights), and
• categoryLevels in host.json does not seem to be respected.

The issue was duplicated in a sample application below in the call to LogWithILogger(). Two other points:

(1) I note that the default filter trace level seems to be hard-coded. Could another Filter be added to allow LogTrace() to work, or should LogTrace() no longer be used? If another Filter can be added, how does one inject the necessary objects into the Function App to permit that?

I'm trying to create a configured object that can be reused along requests in Azure Functions. The example below is in C#. The idea is to avoid the expensive creation of a customized DocumentClient instance for each request. The client field is static and is reused in this example taken from the documentation: