Update AZ-204_lab_02.md Instruction and solution code to use Asynchronous I/O for functions

[Hortlund]

Module/Lab: 02

Fixes Example and solution code giving runtime error

Exception: System.InvalidOperationException: Synchronous operations are disallowed. Call WriteAsync or set AllowSynchronousIO to true instead.

Changes proposed in this pull request: Instructions to use Asynchronous I/O for functions in example and solution code

Relevant Issues link

None

[WigF1]

What issue is this attempting to resolve? The lab steps work as written and the code works as written.

[Hortlund]

@WigF1

I tried again running the example for Echo with the curl examples

curl -X POST -i http://localhost:7071/api/echo -d 3

Functions:

Echo: [GET,POST] http://localhost:7071/api/Echo

GetSettingInfo: [GET,POST] http://localhost:7071/api/GetSettingInfo

Recurring: timerTrigger

For detailed output, run func with --verbose flag. [2024-09-22T13:06:27.739Z] Host lock lease acquired by instance ID '0000000000000000000000004674353B'. [2024-09-22T13:06:47.760Z] Executing 'Functions.Echo' (Reason='This function was programmatically called via the host APIs.', Id=8a048387-d3d0-4554-8a4f-8acf8a8fb37f) [2024-09-22T13:06:47.878Z] C# HTTP trigger function processed a request. [2024-09-22T13:06:47.887Z] Function 'Echo', Invocation id '8a048387-d3d0-4554-8a4f-8acf8a8fb37f': An exception was thrown by the invocation. [2024-09-22T13:06:47.887Z] Result: Function 'Echo', Invocation id '8a048387-d3d0-4554-8a4f-8acf8a8fb37f': An exception was thrown by the invocation. Exception: System.InvalidOperationException: Synchronous operations are disallowed. Call ReadAsync or set AllowSynchronousIO to true instead.

Kestrel doesnt allow synchronous calls by default.

using both SDKS 9.0.100-rc.1.24452.12 and 8.0.400

<PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore" Version="1.2.1" />
<PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Storage" Version="6.6.0" />
<PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Timer" Version="4.1.0" />
<PackageReference Include="Microsoft.Azure.Functions.Worker.Sdk" Version="1.17.2" />
<PackageReference Include="Microsoft.ApplicationInsights.WorkerService" Version="2.22.0" />
<PackageReference Include="Microsoft.Azure.Functions.Worker.ApplicationInsights" Version="1.2.0" />

these are also all the packages i need to be able to run the project without issues as per the examples.

When adding async to the code it works.

This is when running the functions locally.

[msftnutta]

agreed with @WigF1 that currently the code and instruction for this lab working as per normal. Hence, i'll close this PR.

[jv-k]

I'm on MacOS with dotnet v8 and had this exact issue. I fixed it like this:

using Microsoft.Azure.Functions.Worker.Builder;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.DependencyInjection;

var builder = FunctionsApplication.CreateBuilder(args);

builder.Services.Configure<Microsoft.AspNetCore.Server.Kestrel.Core.KestrelServerOptions>(options =>
{
    options.AllowSynchronousIO = true;
});

builder.ConfigureFunctionsWebApplication();

// Application Insights isn't enabled by default. See https://aka.ms/AAt8mw4.
// builder.Services
//     .AddApplicationInsightsTelemetryWorkerService()
//     .ConfigureFunctionsApplicationInsights();

builder.Build().Run();

[Hortlund]

@jv-k Yes that was an option too. My hopes was to not deviate from the default value and change to asynchronous methods instead since that is recommended.