durablefunctionsmonitor.dotnetbackend.targets

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">

    <PropertyGroup>
        <!-- Tells microsoft.net.sdk.functions to include DFM's dll to metadata generation -->
        <FunctionsInDependencies>true</FunctionsInDependencies>
        <!-- Fix for https://github.com/Azure/azure-functions-host/issues/5894 -->
        <_FunctionsSkipCleanOutput>true</_FunctionsSkipCleanOutput>
    </PropertyGroup>

    <!-- Copying statics -->
    <ItemGroup >
        <Content Include="$(MSBuildThisFileDirectory)\..\DfmStatics\**" LinkBase="DfmStatics\">
            <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
        </Content>
    </ItemGroup>

    <!-- 
        This inline task applies DurableFunctionsMonitorRoutePrefix to previously generated DFM's function.json files.
        
        By default, DFM's endpoint is served from root URL (which is typically 'https://<my-functions-host>/api')
        and overshadows all existing HTTP triggers.
        To prevent that from happening and make your DFM endpoint be served from e.g. 'https://<my-functions-host>/api/my-dfm' 
        add the following to your CSPROJ-file:

            <DurableFunctionsMonitorRoutePrefix>my-dfm</<DurableFunctionsMonitorRoutePrefix>
    -->
    <UsingTask
        TaskName="FixDfmPrefixesInFunctionJsonTask"
        TaskFactory="RoslynCodeTaskFactory"
        AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.Core.dll" >
        <ParameterGroup>
            <FolderWithDfmFunctions ParameterType="System.String" />
            <DfmRoutePrefix ParameterType="System.String" />
        </ParameterGroup>
        <Task>
        <Using Namespace="System"/>
        <Using Namespace="System.IO"/>
        <Using Namespace="System.Text.RegularExpressions"/>
        <Code Type="Fragment" Language="cs">
        <![CDATA[

            Log.LogMessage(MessageImportance.High, $"#DurableFunctionsMonitor: applying '{DfmRoutePrefix}' route prefix to function.json files in {FolderWithDfmFunctions}");

            var regex = new Regex("\"route\":\\s*\"", RegexOptions.IgnoreCase | RegexOptions.Compiled);

            bool dfmFunctionsFound = false;
            foreach(var folder in Directory.EnumerateDirectories($"{FolderWithDfmFunctions}", "Dfm*"))
            {
                string functionJsonPath = Path.Combine(folder, "function.json");
                if(!File.Exists(functionJsonPath))
                {
                    continue;
                }

                string json = File.ReadAllText(functionJsonPath);

                var match = regex.Match(json);
                if(match.Success)
                {
                    string before = json.Substring(0, match.Index);
                    string after = json.Substring(match.Index + match.Length);
                    
                    if(after.StartsWith(DfmRoutePrefix))
                    {
                        continue;
                    }

                    json = $"{before}\"route\": \"{DfmRoutePrefix}/{after}";

                    File.WriteAllText(functionJsonPath, json);

                    dfmFunctionsFound = true;
                    Log.LogMessage(MessageImportance.High, $"#DurableFunctionsMonitor: modified {functionJsonPath}");
                }
            }

            if(!dfmFunctionsFound)
            {
                Log.LogWarning("#DurableFunctionsMonitor: Couldn't find any DFM functions in output folder. Make sure you called DfmEndpoint.Setup() in your code.");
            }
        ]]>
        </Code>
        </Task>
    </UsingTask>

    <Target Name="FixDfmPrefixesInFunctionJsonAfterBuild" 
        AfterTargets="_GenerateFunctionsPostBuild" 
        DependsOnTargets="_GenerateFunctionsPostBuild"
        Condition="$(DurableFunctionsMonitorRoutePrefix) != ''"
    >
        <FixDfmPrefixesInFunctionJsonTask FolderWithDfmFunctions="$(TargetDir)" DfmRoutePrefix="$(DurableFunctionsMonitorRoutePrefix)"/>
    </Target>

    <Target Name="FixDfmPrefixesInFunctionJsonAfterPublish" 
        AfterTargets="_FunctionsPostPublish" 
        DependsOnTargets="_FunctionsPostPublish"
        Condition="$(DurableFunctionsMonitorRoutePrefix) != ''"
    >
        <FixDfmPrefixesInFunctionJsonTask FolderWithDfmFunctions="$(PublishDir)" DfmRoutePrefix="$(DurableFunctionsMonitorRoutePrefix)"/>
    </Target>

</Project>