I'm not saying it was built with Azure Functions, but it was definitely built with Azure Functions.

How to fix “The listener for function was unable to start. Out of retries creating lease for partition 0”

Another pretty quick one – trying to debug Azure Functions fails with a confusing error message about failing to create a lease for a partition. But as usual, the fix is (probably) simple, and this article explains what to do :) So, hey future me, finding this article on Google! 🙋‍♂️ Let’s get to it, then! Problem When trying to debug your Azure Function, you get an error somewhat like this: The listener for function [function name] was unable to start. Microsoft.Azure.EventHubs.Processor: Out of retries…Continue reading How to fix “The listener for function was unable to start. Out of retries creating lease for partition 0”

CORS errors.

Azure Functions suddenly throwing CORS errors when ran locally? Easy fix(es)!

In this article, I’m listing the quick fixes to your Azure Functions suddenly throwing seemingly random and very unexpected CORS errors. I have run into this so many times that I had to list these (admittedly simple) fixes in order of importance purely for myself – but perhaps some of these will help you as well! 😁 CORS issues can be frustrating but the issue is usually, simple to fix – as long as you know what you are doing. But first, let’s take a…Continue reading Azure Functions suddenly throwing CORS errors when ran locally? Easy fix(es)!

I'm not saying it was built with Azure Functions, but it was definitely built with Azure Functions.

How to fix “Microsoft.WindowsAzure.Storage: Server encountered an internal error. Please try again after some time.” when using IoTHub trigger for Azure Functions?

One more article before Christmas! 😁 This time, I’ll be fixing a function that’s triggering based on new messages received through my IoT Hub in my Azure Functions project. Technically speaking, this is super simple to implement – your function needs to define an IoTHubTrigger, with an Event Hub name and usually a Connection String (I don’t know why I’m Sentence Casing that, too, but I’ll stick to it!) You can tap a practically unlimited number of Azure Function triggers to any Event Hubs (or…Continue reading How to fix “Microsoft.WindowsAzure.Storage: Server encountered an internal error. Please try again after some time.” when using IoTHub trigger for Azure Functions?

Azure Functions CLI - such a pretty logo for such an awesome functionality

Azure Function build fails with “Mono.Cecil.AssemblyResolutionException: Failed to resolve assembly: Microsoft.AspNetCore.Mvc.Core”

Another fun one with Azure Functions! At least it’s a simple one: this time, I ran into a weird issue while doing some code reusing – well, copy-pasting – between a couple of different projects. I was lovingly hand-crafting some Azure Functions, while suddenly the Azure Functions host would throw this in ugly red letters: Mono.Cecil.AssemblyResolutionException: Failed to resolve assembly: ‘Microsoft.AspNetCore.Mvc.Core, Version=3.1.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60’ at Mono.Cecil.BaseAssemblyResolver.Resolve(AssemblyNameReference name, ReaderParameters parameters) at Mono.Cecil.BaseAssemblyResolver.Resolve(AssemblyNameReference name) at Mono.Cecil.DefaultAssemblyResolver.Resolve(AssemblyNameReference name) at Mono.Cecil.MetadataResolver.Resolve(TypeReference type) at Mono.Cecil.ModuleDefinition.Resolve(TypeReference type) at Mono.Cecil.TypeReference.Resolve() at MakeFunctionJson.AttributeExtensions.IsWebJobsAttribute(CustomAttribute…Continue reading Azure Function build fails with “Mono.Cecil.AssemblyResolutionException: Failed to resolve assembly: Microsoft.AspNetCore.Mvc.Core”

Azure Functions CLI - such a pretty logo for such an awesome functionality

How to fix “Unable to cast object of type ‘System.Net.Http.HttpRequestMessage’ to type ‘Microsoft.AspNetCore.Http.HttpRequest’.”

This article explains how to fix an issue where your Azure Functions function (yes, that’s a capital F and a lowercase f to denote the difference between the product and the piece of compute) fails to fire when a POST request comes in, even though it’s configured to do so, and instead throws a somewhat confusing error message about HttpRequestMessage not being castable to HttpRequest – even though you KNOW HttpRequestMessage works just fine for receiving POST requests with payload! So, why is this happening…Continue reading How to fix “Unable to cast object of type ‘System.Net.Http.HttpRequestMessage’ to type ‘Microsoft.AspNetCore.Http.HttpRequest’.”

When my Azure Function doesn't build

ILogger binding suddenly failing for Azure Functions – what to do?

This article explains another fun issue that you might run into when developing Azure Functions in your local environment. It was weird how unclear the few results were that I could find. And the issue is just… very hazy in general. But I was able to track the issue down, and thought I’d document the solution :) It’s for myself, really, because I’m pretty sure I’ll run into this one again. But if you find it useful, good for you! 😉 Problem So what is…Continue reading ILogger binding suddenly failing for Azure Functions – what to do?

Azure DevOps - Always Be Shipping!

How to update application settings of an Azure Functions App in Azure DevOps Pipeline

This article aims to patch one annoying gap in Microsoft’s documentation: how, exactly, do you update Azure Function App’s application settings using an Azure DevOps build/release pipeline? It sounds easy, and something that should happen almost automatically – and for Azure Web Apps (or App Services, as they are often called) it IS practically automatic. But for Azure Functions, it isn’t. And the docs aren’t perfect. Let me try and fix that. Problem Azure Functions won’t take your appsettings.json file, “mapping” your variable groups or…Continue reading How to update application settings of an Azure Functions App in Azure DevOps Pipeline

Azure Functions CLI - such a pretty logo for such an awesome functionality

“Missing value for AzureWebJobsStorage in local.settings.json” when debugging Azure Functions locally?

Another day, another issue with Azure Functions! For such a simple and powerful tool, it sure does produce a lot of topics for blog articles! 😁 So, in this article, I’m explaining a couple of possible reasons why you might get an error along the lines of “Missing value for AzureWebJobsStorage” when debugging Azure Functions locally. But before jumping into the solution(s), let’s take a closer look at the issue at hand, shall we? Problem When firing up your Azure Functions project locally, this error…Continue reading “Missing value for AzureWebJobsStorage in local.settings.json” when debugging Azure Functions locally?

Elastic Premium plan? It's got potential.

How to change Azure Functions from Consumption to Premium Elastic plan?

Sometimes, you need to change the hosting model (or tier) for your resources on Azure. Maybe you’ve outgrown whatever you’ve originally selected, maybe you’ve got too much cash on your hands, or maybe you’re like me, and you get absolutely and completely fed up with the cold starts for your Azure Function apps on the Consumption plan and want to use the Premium Elastic plan instead. For these situations, you have the possibility of changing the hosting tier – the plan – you’re on. Although,…Continue reading How to change Azure Functions from Consumption to Premium Elastic plan?

When my Azure Function doesn't build

How to fix “System.IO.FileSystem: Could not find a part of the path \AppData\Local\AzureFunctionsTools\Releases\3.17.0\workers. Value cannot be null. (Parameter ‘provider’)” when running Azure Functions locally?

Well, that title is a mouthful. But it’s the topic for today, so what can you do? That said, this article should be pretty topical, as the issue started popping up only a few days ago. Chances are it’ll be patched soon enough, but in the meantime, it’s always useful to document the fix! Problem When running or debugging Azure Functions locally, your runtime just blurts our this error and fails to compile your functions: [2021-01-11T10:28:11.495Z] A host error has occurred during startup operation ‘0d00defa-b8bd-4fb8-9794-b0e5950a4c38’.…Continue reading How to fix “System.IO.FileSystem: Could not find a part of the path \AppData\Local\AzureFunctionsTools\Releases\3.17.0\workers. Value cannot be null. (Parameter ‘provider’)” when running Azure Functions locally?

Say "Dependency Injection" one more time I DARE YOU

How to inject EF Core DbContext in an Azure Function

Ah, one more on the related topics of different configurations for your Azure Function apps. In this article, I will describe how you can configure the Entity Framework Core database context to be injected into your Azure Functions App. In my experience, this is a very typical and often-needed model to structure your Azure Functions. Therefore, while tooling and templates aren’t quite there, it’s worthwhile to document how to do this somewhere – well, here. Solution I’ve posted before about how to instantiate a database…Continue reading How to inject EF Core DbContext in an Azure Function

Azure Functions CLI - such a pretty logo for such an awesome functionality

How to configure Azure Function’s startup

Azure Functions use dependency injection, and that allows us to define all kinds of prebuilt or custom-built services as being available for our functions really easily. This is a really easy way to initialize scoped resources to be used in your different functions… But how do you actually configure them in an Azure Functions App? Problem Okay, a step back – there’s a bit of a problem that we need to resolve before we can proceed with the configuration. When you create a new Azure…Continue reading How to configure Azure Function’s startup

Dependency hell

How to resolve “Microsoft.Data.SqlClient is not supported on this platform.” in an Azure Function App?

Hah – another interesting one. This article describes how to resolve an error along the lines of “Microsoft.Data.SqlClient: Microsoft.Data.SqlClient is not supported on this platform.“, thrown by the Azure Functions host. Apparently, you can run into this issue either on your local development machine or even in Azure. Problem For me, this error popped up after some house cleaning tasks – dependency updates, merging feature branches… You know the stuff. And suddenly, while the Azure Function App would build and run just fine, my SQL…Continue reading How to resolve “Microsoft.Data.SqlClient is not supported on this platform.” in an Azure Function App?

Azure Functions runtime throws an "Insufficient memory to continue the execution of the program." error. What do?

How to resolve error “Insufficient memory to continue the execution of the program.” when debugging Azure Functions locally?

This article describes a solution to an error “Insufficient memory to continue the execution of the program.” I was debugging an Azure Function locally and ran into it – it stopped my Azure Function from starting at all. So, this is what I got: Insufficient memory to continue the execution of the program. Ohh… kay..? My development machines have plenty of RAM, surely enough to run an Azure Function! Hell, I’m sure I have enough memory to have Google Chrome running while debugging a pesky…Continue reading How to resolve error “Insufficient memory to continue the execution of the program.” when debugging Azure Functions locally?

Azure Functions Core Tools (2.4.432) Function Runtime Version: 2.0.12332.0 - The system cannot find the file specified. Press any key to continue . . .

Azure Functions host quits with “The system cannot find the file specified”

So, another interesting issue I ran into when developing Azure Functions locally. What an endless bag of funsies! 😁 This time, the issue was simple but infuriating – my Azure Functions host would just silently close when debugging: none of the breakpoints would be hit, no information would be logged anywhere. Azure Functions Core Tools (2.4.432 Commit hash: 3371a87e0fce2aa35986c0de8e77d5d618163b91) Function Runtime Version: 2.0.12332.0 The system cannot find the file specified Press any key to continue . . . I first encountered this by the Azure…Continue reading Azure Functions host quits with “The system cannot find the file specified”

Azure Functions host be like ...

How to extract more information out of your Azure Functions host failing silently?

I dont’ know about you, but it’s happened to me a few times: fire up your Azure functions project, hit F5 to start debugging, project builds without errors, Azure Functions host starts… And shuts down right away. This article has a few quick and simple tips on how to extract a bit more information from Azure Functions host (func.exe), when it’s just silently failing. This means by default you won’t get any information about what’s going wrong. However, a couple of steps should get you…Continue reading How to extract more information out of your Azure Functions host failing silently?

Azure Functions CLI - such a pretty logo for such an awesome functionality

How to enable verbose logging for Azure Functions?

This post describes how you can easily enable debug/verbose information for your Azure Functions for a lightweight and built-in way to extract just a bit more information out of your Azure Function executions. There’s different methods available for Azure and your local development environment. Problem Azure Functions are awesome. But by default, your tools on gathering information without some additional configuration are not that great. The “monitor” view of the function doesn’t give you more than an excerpt of the console. This applies not only…Continue reading How to enable verbose logging for Azure Functions?

Azure Functions CLI - such a pretty logo for such an awesome functionality

How to access Entity Framework Core’s DbContext in an Azure Function?

This post describes how you can access your Entity Framework Core model classes and the database context in your Azure Functions. In my example I’m using EF Core 2.1, but the main principle should be the same for later versions as well. Please note, that I use Azure functions runtime v2 (but it should work the same in v3 !) Another easy one, that I was unable to find much guidance on! But first, let’s start with the basics. Why would you want to have…Continue reading How to access Entity Framework Core’s DbContext in an Azure Function?

Azure Functions CLI - such a pretty logo for such an awesome functionality

Sudden “Function compilation error” for an Azure Function

Welp – another interesting error encountered while deploying Azure Functions to Azure. So, everything runs nicely locally, but when you deploy your well-tested, functional and pretty code to run them in the cloud, you’ll just get these ugly and unfriendly errors. Long story short, “Function compilation error” is what you’re faced with. Example error below: Function compilation error Microsoft.CodeAnalysis.Scripting.CompilationErrorException : Script compilation failed. at async Microsoft.Azure.WebJobs.Script.Description.DotNetFunctionInvoker.CreateFunctionTarget(CancellationToken cancellationToken) at C:\azure-webjobs-sdk-script\src\WebJobs.Script\Description\DotNet\DotNetFunctionInvoker.cs : 314 at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at async Microsoft.Azure.WebJobs.Script.Description.FunctionLoader`1.GetFunctionTargetAsync[T](Int32 attemptCount) at C:\azure-webjobs-sdk-script\src\WebJobs.Script\Description\FunctionLoader.cs : 55 at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at async…Continue reading Sudden “Function compilation error” for an Azure Function

Low-code / no-code basically means serverless

How to remove Azure Functions without deleting the Functions App?

Have you ever run into a situation, where you just wanted to remove the currently standing function definitions from your app service without actually nuking the whole Functions app? I have! App Service configuration is usually easy to manage programmatically or by scripting, so even if you need to redo the deployment, it should be fairly straightforward. But what if you don’t have the setup scripted, and have already configured everything the way you like it – you’d really like to NOT nuke the whole…Continue reading How to remove Azure Functions without deleting the Functions App?