Fix AzureBicepResource file-not-found error when using templateFile with AzurePublishingContext

[Copilot]

Description

AzureBicepResource with a templateFile parameter failed during AzurePublishingContext.WriteModelAsync() with "Could not find file" errors. GetBicepTemplateFile() combined paths without copying the file to the output directory

Changes:

• GetBicepTemplateFile(): When a TemplateFile is specified, return it directly without combining the output directory path.
• Test: Added AzureBicepResourceWithTemplateFile_CanBePublished to validate end-to-end publishing with template files

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
  • No
• Does the change require an update in our Aspire docs?
  • Yes
  • No

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• aka.ms
  • Triggering command: /usr/local/bin/bicep /usr/local/bin/bicep build /tmp/aspire-bicepHgBrjy/env-acr.module.bicep --stdout (dns block)
  • Triggering command: /usr/local/bin/bicep /usr/local/bin/bicep build /tmp/aspire-bicepccCXB9/teststorage.module.bicep --stdout (dns block)
  • Triggering command: /usr/local/bin/bicep /usr/local/bin/bicep build /tmp/aspire-bicep8yq5hz/env.module.bicep --stdout (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Failed to write Azure Bicep templates: Could not find file with AzurePublishingContext</issue_title>
<issue_description>Using an AzureBicepResource with a template file and using AzurePublishingContext to publish all the bicep files, results in an exception:

12:59:32 (publish-custom) ✗ Failed to write Azure Bicep templates: Could not find file
'C:\Users\eerhardt\AppData\Local\Temp\aspire-bicepwqooyya3.vit\front-door-appservice.bicep'. (0.0s)
12:59:32 (publish-custom) ✗ [ERR] Failed to write Azure Bicep templates to
C:\Users\eerhardt\source\repos\AspireApp4\AspireApp4.AppHost\aspire-output\root\templates
12:59:32 (publish-custom) ✗ [ERR] Step 'publish-custom' failed.
12:59:32 (publish-custom) ✗ Step 'publish-custom' failed: Could not find file
'C:\Users\eerhardt\AppData\Local\Temp\aspire-bicepwqooyya3.vit\front-door-appservice.bicep'.
12:59:32 (pipeline-execution) ✗ [ERR] Step 'publish-custom' failed: Could not find file
'C:\Users\eerhardt\AppData\Local\Temp\aspire-bicepwqooyya3.vit\front-door-appservice.bicep'.
12:59:32 (pipeline-execution) ✗ Failed

Repo steps

aspire do pubilsh-custom the following AppHost:

#pragma warning disable ASPIREPIPELINES001
#pragma warning disable ASPIREPIPELINES004
#pragma warning disable ASPIREAZURE001

using Aspire.Hosting.Azure;
using Aspire.Hosting.Pipelines;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;

var builder = DistributedApplication.CreateBuilder(args);

var apiService = builder.AddProject<Projects.AspireApp4_ApiService>("apiservice")
    .WithHttpHealthCheck("/health");

var frontend = builder.AddProject<Projects.AspireApp4_Web>("webfrontend")
    .WithExternalHttpEndpoints()
    .WithHttpHealthCheck("/health")
    .WithReference(apiService)
    .WaitFor(apiService);

builder.AddAzureFrontDoor("afd", frontend);

builder.Pipeline.AddStep("publish-custom", async context =>
{
    var outputPath = Path.Combine(context.Services.GetRequiredService<IPipelineOutputService>().GetOutputDirectory(), "root");
    var outputDirectory = new DirectoryInfo(outputPath);
    outputDirectory.Create();

    var templates = new DirectoryInfo(Path.Join(outputDirectory.FullName, "templates"));
    templates.Create();

    var azureProvisioningOptions = context.Services.GetRequiredService<IOptions<AzureProvisioningOptions>>().Value;

    var azPublishContext = new AzurePublishingContext(templates.FullName, azureProvisioningOptions, context.Services, context.Logger, context.ReportingStep);
    var azureEnvironmentResource = context.Model.Resources.OfType<AzureEnvironmentResource>().FirstOrDefault() ?? throw new InvalidOperationException("AzureEnvironmentResource not found in the model.");
    await azPublishContext.WriteModelAsync(context.Model, azureEnvironmentResource, context.CancellationToken).ConfigureAwait(false);
});

builder.Build().Run();

internal static class DeploymentExtensions
{
    public static IResourceBuilder<AzureBicepResource> AddAzureFrontDoor(
        this IDistributedApplicationBuilder builder,
        [ResourceName] string name,
        IResourceBuilder<ProjectResource> appServiceWebsite)
    {
        builder.AddAzureProvisioning();

        var frontDoorName = $"{name}-afd";
        var frontdoor = new AzureBicepResource(frontDoorName, "front-door-appservice.bicep");

        return builder.AddResource(frontdoor)
            .WithParameter("frontDoorName", frontDoorName)
            .WithParameter("appServiceHostName", appServiceWebsite.Resource.Name);
    }
}

with front-door-appservice.bicep:

param frontDoorName string
param appServiceHostName string

@description('Location for all resources, needed because Aspire always injects a location parameter')
param location string = resourceGroup().location

resource frontDoorProfile 'Microsoft.Cdn/profiles@2024-02-01' = {
  name: take('${frontDoorName}${uniqueString(resourceGroup().id)}', 50)
  location: 'Global'
  sku: {
    name: 'Premium_AzureFrontDoor'
  }
}

resource frontDoorEndpoint 'Microsoft.Cdn/profiles/afdEndpoints@2025-06-01' = {
  parent: frontDoorProfile
  name: take('${frontDoorName}-endp-${uniqueString(resourceGroup().id)}', 50)
  location: 'Global'
  properties: {
    enabledState: 'Enabled'
  }
}

resource originGroup 'Microsoft.Cdn/profiles/originGroups@2025-06-01' = {
  parent: frontDoorProfile
  name: take('appservice-origin-group-${uniqueString(resourceGroup().id)}', 50)
  properties: {
    loadBalancingSettings: {
      sampleSize: 4
      successfulSamplesRequired: 3
      additionalLatencyInMilliseconds: 50
    }
    healthProbeSettings: {
      probePath: '/'
      probeRequestType: 'HEAD'
      probeProtocol: 'Https'
      probeIntervalInSeconds: 240
    }
    sessionAffinityState: 'Disabled'
  }
}

resource origin 'Microsoft.Cdn/profiles/originGroups/origins@2025-06-01' = {
  parent: originGroup
  name: take('appservice-orig...

</details>



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- Fixes dotnet/aspire#13967

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[github-actions]

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.sh | bash -s -- 13968

Or

• Run remotely in PowerShell:

iex "& { $(irm https://raw.githubusercontent.com/dotnet/aspire/main/eng/scripts/get-aspire-cli-pr.ps1) } 13968"

[Copilot]

Pull request overview

This PR fixes a bug where AzureBicepResource with a templateFile parameter failed during Azure publishing with "Could not find file" errors. The issue occurred because GetBicepTemplateFile() incorrectly combined user-provided template file paths with a temporary directory parameter, resulting in invalid file paths when attempting to copy the template files.

Changes:

• Modified GetBicepTemplateFile() to return the template file path directly when TemplateFile is specified, instead of combining it with the directory parameter
• Added three unit tests to verify the corrected behavior of GetBicepTemplateFile() with template files vs template strings
• Added an integration test to validate end-to-end publishing with relative template file paths

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/Aspire.Hosting.Azure/AzureBicepResource.cs	Fixed GetBicepTemplateFile() to return TemplateFile path directly without incorrectly combining it with directory parameter
tests/Aspire.Hosting.Azure.Tests/AzureBicepResourceTests.cs	Added three unit tests verifying GetBicepTemplateFile() behavior with template files and strings
tests/Aspire.Hosting.Azure.Tests/AzureEnvironmentResourceTests.cs	Added integration test using RemoteExecutor to validate end-to-end publishing with relative template file paths

[eerhardt]

/backport to release/13.1

[github-actions]

Started backporting to release/13.1: https://github.com/dotnet/aspire/actions/runs/21179320631