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Error loading NuGets with Azure Functions Core tools (2.0.1-beta.31)

Azure Functions Core Tools (2.0.1-beta.31) Function Runtime Version: 2.0.11888.0

I'm writing v1 functions using F#. I use Paket to bring in NuGets and build the code into precompiled assemblies as part of my deployment. I've had this working for many months.

I think local testing stopped running today once I updated to 2.0.1-beta.31.

Now when I test using func host start, I see this multiple instances of this error:

[7/18/18 9:14:32 PM] Could not load file or assembly 'Octokit, Version=0.27.0.0, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.
[7/18/18 9:14:32 PM] Could not load file or assembly 'FSharp.Data, Version=2.4.2.0, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.
[7/18/18 9:14:32 PM] Could not load file or assembly 'FSharp.Control.AsyncSeq, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.

I thought this had to do with assembly binding redirections, but now I don't think so because Octokit doesn't (shouldn't) have any relevant external dependencies.

I've tested this on both Mac and Windows, and I see the same errors on both platforms.

Solution

  • There are two versions of the Azure Functions runtime:

    • v1, which is built on the full .NET Framework and is Windows-only (GA)
    • v2, which is built on .NET Standard 2.1 and is cross-platform (preview)

    These are essentially two separate "branches" of Functions. Accordingly there are two versions of Azure Functions Core Tools:

    • 1.x, which runs the v1 Functions runtime
    • 2.x, which runs the v2 Functions runtime

    You have a 2.x Core Tools version installed and are trying to run v1 functions on it, which is why you're experiencing errors. You'll need to revert to the latest 1.x version of Azure Functions Core Tools.

    re: Functions v1 and v2 in general, v2 is where our engineering efforts will be focused. For this reason we recommend users consider migrating to or starting new projects in v2. There is no current plan to deprecate v1, and if we were to, v1 would remain generally available for at least a year after v2 becomes General Availability (expected sometime this fall).