Debugging

Debugging Source Symbols in NuGet packages

It’s possible to debug into the ServiceStack source code when using the ServiceStack NuGet packages.

Normally you could enable this after enabling SymbolSource integration in VisualStudio but as the SymbolSource has been unavailable for months it’s no longer a reliable source for Debug Symbols.

Instead we’re publishing the NuGet package symbols after each release to: github.com/ServiceStack/Assets/tree/master/nuget

The easiest way to download all .pdb is by downloading all-pdbs.zip under the release version you’re interested in then adding the path where you’ve extracted the pdb’s to as a Symbol Source Location:

1. Go to Tools -> Options -> Debugger -> General
2. Uncheck Enable Just My Code, Enable .NET Framework source stepping and Require source files to exactly match the original version
3. Check Enable source server support
4. In the Tools -> Options -> Debugger -> Symbols dialog, under the Symbol file (.pdb) locations section by clicking the New Folder icon and add the following urls (in order):
   • http://referencesource.microsoft.com/symbols
   • C:\path\to\symbols
   • http://msdl.microsoft.com/download/symbols

And with that you should now be able to debug into the source code of any NuGet package (who publishes their Symbols) directly from within your application!

Alternatives Debugging Solutions

GitLink is another solution for debugging source code in NuGet packages.

Otherwise the most reliable solution for debugging ServiceStack source code is to download the source code for the release on Github you want to debug, build the VS.NET Solution locally using Debug configuration then change your ServiceStack references to use your local .dll.

Configuration

DebugMode

ServiceStack allows additional debug information when in DebugMode, which is automatically set by default in Debug builds or explicitly with:

SetConfig(new HostConfig { DebugMode = true });

In addition, users with the Admin role or Requests with an AuthSecret can also view Debug Info in production.

StrictMode

You can configure Strict Mode in ServiceStack to enforce stricter behavior and have it throw Exceptions when it sees certain failure conditions. To enable Strict Mode across all libraries use:

Env.StrictMode = true;

Otherwise to just enable StrictMode for ServiceStack:

SetConfig(new HostConfig {
    StrictMode = true
})

When enabled ServiceStack will perform runtime checks to catch invalid state, currently:

• Checks if Services return Value Types
• Checks if UserSession has circular dependencies
• Fails fast for exceptions on Startup

Admin Role

Users in the Admin role have super-user access giving them access to any services or plugins protected with Roles and Permissions.

AuthSecret

You can use Config.AdminAuthSecret to specify a special string to give you admin access without having to login by adding ?authsecret=xxx to the query string, e.g:

SetConfig(new HostConfig { AdminAuthSecret = "secretz" });

By-pass protected services using query string:

/my-service?authsecret=secretz

Debug Links

To provide better visibility to the hidden functionality in ServiceStack we’ve added Debug Info links section to the /metadata page which add links to any Plugins with Web UI’s, e.g:

The Debug Links section is only available in DebugMode.

You can add links to your own Plugins in the metadata pages with:

appHost.GetPlugin<MetadataFeature>()
    .AddPluginLink("swagger-ui/", "Swagger UI");

appHost.GetPlugin<MetadataFeature>()
    .AddDebugLink("?debug=requestinfo", "Request Info");

AddPluginLink adds links under the Plugin Links section and should be used if your plugin is publicly visible, otherwise use AddDebugLink for plugins only available during debugging or development.

Startup Errors

When plugins are registered their Exceptions are swallowed and captured in AppHost.StartupErrors so an individual Rogue plugin won’t prevent your ServiceStack AppHost from starting. But when a plugin doesn’t work properly it can be hard to determine the cause was due to an Exception occuring at Startup.

Alternatively enable StrictMode to have StartUp Exceptions thrown on StartUp.

Debug Inspector

All ServiceStack Apps have access to rich introspection and queryability for inspecting remote ServiceStack instances with the new Debug Template.

The Debug Template is a Service in TemplatePagesFeature that’s pre-registered in DebugMode. The Service can also be available when not in DebugMode by enabling it with:

Plugins.Add(new TemplatePagesFeature { 
    MetadataDebugAdminRole = RoleNames.Admin,        // Only allow Admin users
})

This registers the Service but limits it to Users with the Admin role, alternatively you configure an Admin Secret:

SetConfig(new HostConfig { AdminAuthSecret = "secret" })

Which will let you access it by appending the authsecret to the querystring: /metadata/debug?authsecret=secret

Alternatively if preferred you can make the Debug Template Service available to:

Plugins.Add(new TemplatePagesFeature { 
    MetadataDebugAdminRole = RoleNames.AllowAnyUser,  // Allow Authenticated Users
    MetadataDebugAdminRole = RoleNames.AllowAnon,     // Allow anyone
})

Which is the configuration that allows templates.servicestack.net/metadata/debug to be accessible to anyone.

Request Info

ServiceStack’s Request Info feature is useful for debugging requests. Just add ?debug=requestinfo in your /pathinfo and ServiceStack will return a dump of all the HTTP Request parameters to help with debugging interoperability issues. The RequestInfoFeature is only enabled in DebugMode.

To better highlight the presence of Startup Errors a red warning banner will also appear in /metadata pages when in DebugMode, e.g:

The number of Startup Errors is also added to the X-Startup-Errors: n Global HTTP Header so you’ll be able to notice it when debugging HTTP Traffic.

If you prefer that any Plugin Exception is immediately visible you can register this callback in your AppHost to throw a YSOD with your first Startup Error:

AfterInitCallbacks.Add(host => {
    var appHost = (ServiceStackHost)host;
    if (appHost.StartUpErrors.Count > 0)
        throw new Exception(appHost.StartUpErrors[0].Message);
});

Plugins

There are a number of plugins that can help with debugging:

Request Logger

Add an In-Memory IRequestLogger and service with the default route at /requestlogs which maintains a live log of the most recent requests (and their responses). Supports multiple config options incl. Rolling-size capacity, error and session tracking, hidden request bodies for sensitive services, etc.

Plugins.Add(new RequestLogsFeature());

The IRequestLogger is a great way to introspect and analyze your service requests in real-time. Here’s a screenshot from the http://bootstrapapi.servicestack.net website:

It supports multiple queryString filters and switches so you filter out related requests for better analysis and debuggability:

The RequestLogsService is just a simple C# service under-the-hood but is a good example of how a little bit of code can provide a lot of value in ServiceStack’s by leveraging its generic, built-in features.