Refactor AzurePublisher to enable usage in downstream publishers (#8507)

Few refactoring changes to AzurePublisher to enable usage in downstream publishers:

Refactor the logic in AzurePublisher to a new public AzurePublishingContext class.
refactor code in AzurePublisher.PublishAsync to AzurePublishingContext and capture bicep compilation data that is thrown away in the existing AzurePublisher.PublishAsync method

* Restructure AzurePublisher and add AzurePublishingContext

* Few more edits and add an playgroud app for AzurePublisher

* Move SaveToDisk to Publisher

* Edit Playground aspire starter app to use AspireProjectOrPackageReference and call AddAzurePublisher

* Remove AzurePublisher playground app

* Refactor AzurePublishingContext to be public.

* Fix up .sln file

---------

Co-authored-by: Eric Erhardt <[email protected]>

Author: sunandabalu

src/Aspire.Hosting.Azure/AzurePublisher.cs

@@ -4,289 +4,50 @@
 using System.Diagnostics.CodeAnalysis;
 using Aspire.Hosting.ApplicationModel;
 using Aspire.Hosting.Publishing;
-using Azure.Provisioning;
-using Azure.Provisioning.Expressions;
-using Azure.Provisioning.Primitives;
-using Azure.Provisioning.Resources;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 
 namespace Aspire.Hosting.Azure;
 
+/// <summary>
+/// Represents a publisher for deploying distributed application models to Azure using Bicep templates.
+/// </summary>
+/// <remarks>
+/// This class is responsible for processing a distributed application model, generating Bicep templates,
+/// and configuring Azure infrastructure for deployment. It supports parameter resolution, resource grouping,
+/// and output propagation for Azure resources.
+/// </remarks>
+/// <example>
+/// Example usage:
+/// <code>
+/// var publisher = new AzurePublisher("myPublisher", optionsMonitor, provisioningOptions, logger);
+/// await publisher.PublishAsync(model, cancellationToken);
+/// </code>
+/// </example>
+/// <seealso cref="IDistributedApplicationPublisher"/>
 [Experimental("ASPIREAZURE001", UrlFormat = "https://aka.ms/dotnet/aspire/diagnostics#{0}")]
 internal sealed class AzurePublisher(
     [ServiceKey] string name,
     IOptionsMonitor<AzurePublisherOptions> options,
     IOptions<AzureProvisioningOptions> provisioningOptions,
     ILogger<AzurePublisher> logger) : IDistributedApplicationPublisher
 {
-    private AzureProvisioningOptions ProvisioningOptions => provisioningOptions.Value;
-
-    public Task PublishAsync(DistributedApplicationModel model, CancellationToken cancellationToken)
+    /// <summary>
+    /// Publishes the specified distributed application model to Azure using Bicep templates.
+    /// </summary>
+    /// <param name="model">The distributed application model to publish.</param>
+    /// <param name="cancellationToken">A token to monitor for cancellation requests.</param>
+    /// <returns>A task that represents the asynchronous publish operation.</returns>
+    public async Task PublishAsync(DistributedApplicationModel model, CancellationToken cancellationToken)
     {
         var publisherOptions = options.Get(name);
 
-        var infra = new Infrastructure
-        {
-            TargetScope = DeploymentScope.Subscription
-        };
-
-        var environmentParam = new ProvisioningParameter("environmentName", typeof(string));
-        infra.Add(environmentParam);
-
-        var locationParam = new ProvisioningParameter("location", typeof(string));
-        infra.Add(locationParam);
-
-        var principalId = new ProvisioningParameter("principalId", typeof(string));
-        infra.Add(principalId);
-
-        var tags = new ProvisioningVariable("tags", typeof(object))
-        {
-            Value = new BicepDictionary<string>
-            {
-                ["aspire-env-name"] = environmentParam
-            }
-        };
-
-        // REVIEW: Do we want people to be able to change this
-        var rg = new ResourceGroup("rg")
-        {
-            Name = BicepFunction.Interpolate($"rg-{environmentParam}"),
-            Location = locationParam,
-            Tags = tags
-        };
-
         var outputDirectory = new DirectoryInfo(publisherOptions.OutputPath!);
-
         outputDirectory.Create();
 
-        // Process the resources in the model and create a module for each one
-        var moduleMap = new Dictionary<AzureBicepResource, ModuleImport>();
-
-        foreach (var resource in model.Resources.OfType<AzureBicepResource>())
-        {
-            var file = resource.GetBicepTemplateFile();
-
-            var moduleDirectory = outputDirectory.CreateSubdirectory(resource.Name);
-
-            var modulePath = Path.Combine(moduleDirectory.FullName, $"{resource.Name}.bicep");
-
-            File.Copy(file.Path, modulePath, true);
-
-            var identifier = Infrastructure.NormalizeBicepIdentifier(resource.Name);
-
-            var module = new ModuleImport(identifier, $"{resource.Name}/{resource.Name}.bicep")
-            {
-                Name = resource.Name
-            };
-
-            moduleMap[resource] = module;
-        }
-
-        // Resolve parameters *after* writing the modules to disk
-        // this is because some parameters are added in ConfigureInfrastructure callbacks
-        var parameterMap = new Dictionary<ParameterResource, ProvisioningParameter>();
-
-        foreach (var resource in model.Resources.OfType<AzureBicepResource>())
-        {
-            foreach (var parameter in resource.Parameters)
-            {
-                Visit(parameter.Value, v =>
-                {
-                    if (v is ParameterResource p && !parameterMap.ContainsKey(p))
-                    {
-                        var pid = Infrastructure.NormalizeBicepIdentifier(p.Name);
-
-                        var pp = new ProvisioningParameter(pid, typeof(string))
-                        {
-                            IsSecure = p.Secret
-                        };
-
-                        if (!p.Secret && p.Default is not null)
-                        {
-                            pp.Value = p.Value;
-                        }
-
-                        // Map the parameter to the Bicep parameter
-                        parameterMap[p] = pp;
-                    }
-                });
-            }
-        }
-
-        static BicepValue<string> GetOutputs(ModuleImport module, string outputName) =>
-           new MemberExpression(new MemberExpression(new IdentifierExpression(module.BicepIdentifier), "outputs"), outputName);
-
-        BicepFormatString EvalExpr(ReferenceExpression expr)
-        {
-            var args = new object[expr.ValueProviders.Count];
-
-            for (var i = 0; i < expr.ValueProviders.Count; i++)
-            {
-                args[i] = Eval(expr.ValueProviders[i]);
-            }
-
-            return new BicepFormatString(expr.Format, args);
-        }
-
-        object Eval(object? value) => value switch
-        {
-            BicepOutputReference b => GetOutputs(moduleMap[b.Resource], b.Name),
-            ParameterResource p => parameterMap[p],
-            ConnectionStringReference r => Eval(r.Resource.ConnectionStringExpression),
-            IResourceWithConnectionString cs => Eval(cs.ConnectionStringExpression),
-            ReferenceExpression re => EvalExpr(re),
-            string s => s,
-            _ => ""
-        };
-
-        static BicepValue<string> ResolveValue(object val)
-        {
-            return val switch
-            {
-                BicepValue<string> s => s,
-                string s => s,
-                ProvisioningParameter p => p,
-                BicepFormatString fs => BicepFunction2.Interpolate(fs),
-                _ => throw new NotSupportedException("Unsupported value type " + val.GetType())
-            };
-        }
-
-        foreach (var resource in model.Resources.OfType<AzureBicepResource>())
-        {
-            BicepValue<string> scope = resource.Scope?.ResourceGroup switch
-            {
-                // resourceGroup(rgName)
-                string rgName => new FunctionCallExpression(new IdentifierExpression("resourceGroup"), new StringLiteralExpression(rgName)),
-                ParameterResource p => parameterMap[p],
-                _ => new IdentifierExpression(rg.BicepIdentifier)
-            };
-
-            var module = moduleMap[resource];
-            module.Scope = scope;
-            module.Parameters.Add("location", locationParam);
-
-            foreach (var parameter in resource.Parameters)
-            {
-                // TODO: There are a set of known parameter names that we may not be able to resolve.
-                // This is from earlier versions of aspire where infra was split across
-                // azd and aspire. Once the infra moves to aspire, we can throw for 
-                // unresolved "known parameters".
-
-                if (parameter.Key == AzureBicepResource.KnownParameters.UserPrincipalId && parameter.Value is null)
-                {
-                    module.Parameters.Add(parameter.Key, principalId);
-                    continue;
-                }
-
-                var value = ResolveValue(Eval(parameter.Value));
-
-                module.Parameters.Add(parameter.Key, value);
-            }
-        }
-
-        var outputs = new Dictionary<string, BicepOutputReference>();
-
-        // Now find all resources that have deployment targets that are bicep modules
-        foreach (var resource in model.Resources)
-        {
-            if (resource.TryGetLastAnnotation<DeploymentTargetAnnotation>(out var targetAnnotation) &&
-                targetAnnotation.DeploymentTarget is AzureBicepResource br)
-            {
-                var moduleDirectory = outputDirectory.CreateSubdirectory(resource.Name);
-
-                var modulePath = Path.Combine(moduleDirectory.FullName, $"{resource.Name}.bicep");
-
-                var file = br.GetBicepTemplateFile();
-
-                File.Copy(file.Path, modulePath, true);
-
-                // TODO: Resolve parameters for the module and
-                // handle flowing outputs from other modules
-
-                foreach (var parameter in br.Parameters)
-                {
-                    Visit(parameter.Value, v =>
-                    {
-                        if (v is BicepOutputReference bo)
-                        {
-                            // Any bicep output reference needs to be propagated to the top level
-                            outputs[bo.ValueExpression] = bo;
-                        }
-                    });
-                }
-            }
-        }
-
-        // Add parameters to the infrastructure
-        foreach (var (_, pp) in parameterMap)
-        {
-            infra.Add(pp);
-        }
-
-        // Add the parameters to the infrastructure
-        infra.Add(tags);
-
-        // Add the resource group to the infrastructure
-        infra.Add(rg);
-
-        // Add the modules to the infrastructure
-        foreach (var (_, module) in moduleMap)
-        {
-            // Add the module to the infrastructure
-            infra.Add(module);
-        }
-
-        // Add the outputs to the infrastructure
-        foreach (var (_, output) in outputs)
-        {
-            var module = moduleMap[output.Resource];
-
-            var identifier = Infrastructure.NormalizeBicepIdentifier($"{output.Resource.Name}_{output.Name}");
-
-            var bicepOutput = new ProvisioningOutput(identifier, typeof(string))
-            {
-                Value = GetOutputs(module, output.Name)
-            };
-
-            infra.Add(bicepOutput);
-        }
-
-        SaveToDisk(outputDirectory.FullName, infra);
-
-        return Task.CompletedTask;
-    }
-
-    private static void Visit(object? value, Action<object> visitor) =>
-        Visit(value, visitor, []);
-
-    private static void Visit(object? value, Action<object> visitor, HashSet<object> visited)
-    {
-        if (value is null || !visited.Add(value))
-        {
-            return;
-        }
-
-        visitor(value);
-
-        if (value is IValueWithReferences vwr)
-        {
-            foreach (var reference in vwr.References)
-            {
-                Visit(reference, visitor, visited);
-            }
-        }
-    }
-
-    private void SaveToDisk(string outputDirectoryPath, Infrastructure infrastructure)
-    {
-        var plan = infrastructure.Build(ProvisioningOptions.ProvisioningBuildOptions);
-        var compiledBicep = plan.Compile().First();
-
-        logger.LogDebug("Writing Bicep module {BicepName}.bicep to {TargetPath}", infrastructure.BicepName, outputDirectoryPath);
+        var context = new AzurePublishingContext(publisherOptions, provisioningOptions.Value, logger);
 
-        var bicepPath = Path.Combine(outputDirectoryPath, $"{infrastructure.BicepName}.bicep");
-        File.WriteAllText(bicepPath, compiledBicep.Value);
+        await context.WriteModelAsync(model, cancellationToken).ConfigureAwait(false);
     }
 }