Skip to content

Latest commit

 

History

History
82 lines (75 loc) · 3.51 KB

02 Creating an Azure Function.md

File metadata and controls

82 lines (75 loc) · 3.51 KB
Raw

Setting up for Azure Functions

Because at the time of writing, .net 5 isn't supported in the in-process hosting for Azure Functions, I'm following the Isolated Process Worker instructions.

To test locally, you don't need an Azure account, but you do need the Azure Function Core Tools and the Azure CLI

An F# project for an HttpHandler

There aren't (at the time of writing) any templates for the isolated hosting in F#, but we'll make do:

cd EverythingAsCodeFSharp
func init WordValues.Azure --worker-runtime dotnetisolated --language F#

That gets us a C# project with no functions. So now to 'fix' it a bit:

cd WordValues.Azure
rename WordValues_Azure.csproj WordValues.Azure.fsproj
del program.cs

Edit the NuGet package references to include the Http Function extension worker

   <ItemGroup>
     <PackageReference Include="Microsoft.Azure.Functions.Worker.Sdk" Version="1.0.1" OutputItemType="Analyzer"/>
     <PackageReference Include="Microsoft.Azure.Functions.Worker" Version="1.0.0" />
     <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http" Version="3.0.12" />
+    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http" Version="3.0.12" />
   </ItemGroup>

And edit the last ItemGroup node in WordValues.Azure.fsproj to compensate for F# projects not automatically including the files from the source folder

   <ItemGroup>
+    <Compile Include="Function.fs" />
+    <Compile Include="Program.fs" />
-    <None Update="host.json">
+    <None Include="host.json">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
+    <None Include="local.settings.json">
-    <None Update="local.settings.json">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
       <CopyToPublishDirectory>Never</CopyToPublishDirectory>
     </None>
   </ItemGroup>

Create Program.fs to start up the hosting

module WordValues.Azure.Program

open Microsoft.Extensions.Hosting

let [<EntryPoint>] main _ =
    HostBuilder()
        .ConfigureFunctionsWorkerDefaults()
        .Build()
        .Run()
    0

And Function.fs with a do-almost-nothing HttpHandler

module WordValues.Azure.Function

open System.Net
open Microsoft.Azure.Functions.Worker
open Microsoft.Azure.Functions.Worker.Http

[<Function("WordValue")>]
let run ([<HttpTrigger(AuthorizationLevel.Anonymous, "get")>] request:HttpRequestData, executionContext:FunctionContext) : HttpResponseData =
    let response = request.CreateResponse(HttpStatusCode.OK)
    response.Headers.Add("Content-Type", "text/plain; charset=utf-8")
    response.WriteString("Hello")
    response

Now if you use func to start the project it will build and start up a local web server to test the function (you might be asked to allow func.exe's through the local firewall)

func start
...
Azure Functions Core Tools
Core Tools Version:       3.0.3388 Commit hash: fb42a4e0b7fdc85fbd0bcfc8d743ff7d509122ae
Function Runtime Version: 3.0.15371.0

Functions:
        WordValue: [GET] http://localhost:7071/api/WordValue

Opening that Url in the browser you should see the "Hello" message, and the console window should give some information about the function invocation.