Can I develop and test Azure Functions completely offline (no network connection)? I understand Azure Functions can be debugged locally but that's not the same as working completely disconnected from the Azure platform.
I found a few references in the Azure documentation that I interpreted to mean being connected to Azure is required to run Azure Functions, even locally.
FWIW, I'm using the Azure Functions tooling in Visual Studio 2017 (15.3.2)
On
It depends. Some infrastructure (like [Singleton], which is used by Timer) need a storage account since they use blob leases for coordination. Logging can be disabled.
On one extreme, if you're binding to cloud resources (ie, DocDb) or using cloud-based triggers, then clearly you must be online. Some bindings (like blob) can work against a storage emulator, but this a case-by-case basis.
On the other extreme, Azure Functions parameter binding makes it very mock-friendly which would let you invoke your functions directly offline (and also in unit tests) rather than go through the Azure Functions listening + dispatch logic. For example, you can bind a Blob to a Stream or TextReader, and then directly invoke your function and pass them streams that are bound to in-memory or file system. The IAsyncCollector interfaces are also very mock friendly. Our own unit tests in the WebJobs SDK heavily leverage this (see https://github.com/Azure/azure-webjobs-sdk/blob/b8674651654f27a51ffadd0d38b4f89ce246b7a1/test/Microsoft.Azure.WebJobs.Host.UnitTests/Indexers/ReturnValueTests.cs as an example)
The answer is no. Although you can use some bindings in a disconnected way such as Azure Storage through Azure Emulator, not all of them offer a way to work disconnected.