microsoft/aspire · error · InvalidOperationException

Could not find a with name .

Error message

Could not find a {nameof(AzureSqlDatabaseResource)} with name {database.Key}.

What it means

RunAsContainer for Azure SQL throws InvalidOperationException when a database declared on the AzureSqlServerResource has no matching entry in the inner container's database collection. This is an internal consistency check: switching the server to a container emulator must find every database already added to the Azure resource.

Solutions

  1. Ensure all databases are added via sql.AddDatabase(...) before calling RunAsContainer.
  2. Do not manually construct/add AzureSqlDatabaseResource instances that bypass the server's AzureSqlDatabases collection.
  3. Update Aspire packages so all Azure SQL extension versions match.
  4. Inspect the database.Key named in the message and add a matching database to the builder chain.

Example fix

// before
var sql = builder.AddAzureSql("sql").RunAsContainer();
sql.AddDatabase("appdb"); // added after switch — lookup fails

// after
var sql = builder.AddAzureSql("sql");
sql.AddDatabase("appdb");
sql.RunAsContainer();
Defensive patterns

Strategy: validation

Validate before calling

// Ensure all databases are declared before switching to container mode:
var sql = builder.AddAzureSql("sql");
sql.AddDatabase("appdb");
sql.RunAsContainer();

Try / catch

try { sql.RunAsContainer(); }
catch (InvalidOperationException ex) when (ex.Message.Contains("Could not find a AzureSqlDatabaseResource")) { /* restructure: add all databases first */ }

Prevention

When it happens

Trigger: Calling RunAsContainer after databases were added to the Azure SQL server resource in a way that did not register them on the inner container — e.g. adding databases after RunAsContainer, or interleaving extension versions that bypass SetInnerResource registration.

Common situations: Mixed use of direct resource construction and extension methods; adding databases to the server after switching to emulator mode; API version mismatches where the database key maps differ.

Understand the failure class

Background: "Not found" and "does not exist" errors: why "Task not found", "No such folder", and "Can't find" fire when a lookup comes back empty — this error's family across 14 libraries.

Related errors

AI-assisted analysis of microsoft/aspire@25830f84bd (2026-09-16). Data as JSON: /api/errors/c331e976d4642bf3. Report an issue: GitHub.

Appendix: source

Thrown at src/Aspire.Hosting.Azure.Sql/AzureSqlExtensions.cs:206

        }

        var azureResource = builder.Resource;
        var azureDatabases = builder.ApplicationBuilder.Resources
            .OfType<AzureSqlDatabaseResource>()
            .Where(db => db.Parent == azureResource)
            .ToDictionary(db => db.Name);

        RemoveAzureResources(builder.ApplicationBuilder, azureResource, azureDatabases);

        var sqlContainer = builder.ApplicationBuilder.AddSqlServer(azureResource.Name);

        azureResource.SetInnerResource(sqlContainer.Resource);

        foreach (var database in azureResource.AzureSqlDatabases)
        {
            if (!azureDatabases.TryGetValue(database.Key, out var existingDb))
            {
                throw new InvalidOperationException($"Could not find a {nameof(AzureSqlDatabaseResource)} with name {database.Key}.");
            }

            var innerDb = sqlContainer.AddDatabase(database.Key, database.Value.DatabaseName);
            existingDb.SetInnerResource(innerDb.Resource);
        }

        configureContainer?.Invoke(sqlContainer);

        return builder;
    }

    private static void RemoveAzureResources(IDistributedApplicationBuilder appBuilder, AzureSqlServerResource azureResource, Dictionary<string, AzureSqlDatabaseResource> azureDatabases)
    {
        appBuilder.Resources.Remove(azureResource);
        foreach (var database in azureDatabases)
        {
            appBuilder.Resources.Remove(database.Value);
        }

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