/HotChocolate_ThorLogging

Primary LanguageC#

Introduction

This repository shows how to use Thor to enable Tracing on a HotChocolate Api.

In our example, we will generate resolver errors in a HotChocolate Api. HotChocolate will automatically send events about these errors to an EventHub.

We will read these events with a HostedService, which will forward them to a HotChocolate subscription. This is just for convenience, you could instead write them into the console or make another App that's listening to the EventHub and stores the received events in a database.

Getting Started

The Host app is Host.csproj.

You'll need an Azure Blob Storage and an EventHub.

For the blob Storage, you can use Azurite (see the official Azurite doc as well as the Azure Cloud Storage connectionString override mechanism)

docker pull mcr.microsoft.com/azure-storage/azurite
docker run -p 10000:10000 -p 10001:10001 mcr.microsoft.com/azure-storage/azurite

Or you can use an azure resource.

Both resources' connectionStrings are to be stored in the appsettings.json File.

Testing the tracing feature

Our HotChocolate api automatically forwards all exceptions and resolver issues to the configured EventBus. This is done with just two lines in the Startup class (AddTracing() and AddThorLogging()).

We will use a HostedService to listen to new events from the EventHub. This hosted service will forward the events to a HotChocolate subscription onEvent that we can consume via a compatible GraphQL Client.

The subscription

A BananaCakepop GraphQL Client is available on the endpoint (http://localhost:XXXX).

Open your BananaCakepop GraphQL client and run the following request:

subscription sub {
  onEvent(eventType: "trace"){
    id
    activityId
    applicationId
    level
    message
    payloads{
      statusCode
      statusText
    }
    providerName
    taskId
  }
}

Each time a new event is received from the EventHub, you'll see it here.

Now open another GraphQL Client and run the following Query:

query f1 {
  nonNullableFieldWithNullResult
}

You'll see events appear in the subscription: requests and traces