Metrics

Metrics are captured during execution if ExecutionOptions.EnableMetrics property is set to true. By default, metrics collection is disabled to improve performance.

Enabling metrics can help you determine performance issues within a resolver or validation. Field metrics are captured using Field Middleware and the results are returned as a PerfRecord array on the ExecutionResult. You can then generate Apollo Tracing data with the EnrichWithApolloTracing() extension method.

var start = DateTime.UtcNow;

var executor = new DocumentExecutor();
ExecutionResult result = executor.ExecuteAsync(_ =>
{
  _.Schema = schema;
  _.Query = "...";
  _.EnableMetrics = true;
  _.FieldMiddleware.Use<InstrumentFieldsMiddleware>();
});

result.EnrichWithApolloTracing(start);

Alternatively, you can use the ApolloTracingDocumentExecuter to append the tracing results to the execution; this is ideal when wiring up GraphQL via dependency injection.

services.AddGraphQL(b => b
    .AddSchema<StarWarsSchema>()
    .AddMetrics(true)
    .AddDocumentExecuter<ApolloTracingDocumentExecuter>()
    .AddSystemTextJson());

Here is a sample of the results:

{
  "data": {
    "hero": {
      "name": "R2-D2",
      "friends": [
        {
          "name": "Luke"
        },
        {
          "name": "C-3PO"
        }
      ]
    }
  },
  "extensions": {
    "tracing": {
      "version": 1,
      "startTime": "2018-07-28T21:39:27.160902Z",
      "endTime": "2018-07-28T21:39:27.372902Z",
      "duration": 212304000,
      "parsing": {
        "startOffset": 57436000,
        "duration": 21985999
      },
      "validation": {
        "startOffset": 57436000,
        "duration": 21985999
      },
      "execution": {
        "resolvers": [
          {
            "path": [
              "hero"
            ],
            "parentType": "Query",
            "fieldName": "hero",
            "returnType": "Character",
            "startOffset": 147389000,
            "duration": 2756000
          },
          {
            "path": [
              "hero",
              "name"
            ],
            "parentType": "Droid",
            "fieldName": "name",
            "returnType": "String",
            "startOffset": 208043000,
            "duration": 396000
          },
          {
            "path": [
              "hero",
              "friends"
            ],
            "parentType": "Droid",
            "fieldName": "friends",
            "returnType": "[Character]",
            "startOffset": 208533000,
            "duration": 1067999
          },
          {
            "path": [
              "hero",
              "friends",
              0,
              "name"
            ],
            "parentType": "Human",
            "fieldName": "name",
            "returnType": "String",
            "startOffset": 210501000,
            "duration": 33999
          },
          {
            "path": [
              "hero",
              "friends",
              1,
              "name"
            ],
            "parentType": "Droid",
            "fieldName": "name",
            "returnType": "String",
            "startOffset": 210542000,
            "duration": 3000
          }
        ]
      }
    }
  }
}

Also you could create a listener that hooks in after the execution and uses the Apollo tracing data to synthesize some other traces, for example, for Application Insights.