Custom Instrumentation

Learn how to capture performance data on any action in your app.

To capture transactions and spans customized to your organization's needs, you must first set up performance monitoring.

To instrument certain regions of your code, you can create transactions to capture them.

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// Transaction can be started by providing, at minimum, the name and the operation
var transaction = SentrySdk.StartTransaction(
  "test-transaction-name",
  "test-transaction-operation"
);

// Transactions can have child spans (and those spans can have child spans as well)
var span = transaction.StartChild("test-child-operation");

// ...
// (Perform the operation represented by the span/transaction)
// ...

span.Finish(); // Mark the span as finished
transaction.Finish(); // Mark the transaction as finished and send it to Sentry

For example, if you want to create a transaction for a user interaction in your application:

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// Let's say this method is invoked when a user clicks on the checkout button of your shop
public async Task PerformCheckoutAsync()
{
  // This will create a new Transaction for you
  var transaction = SentrySdk.StartTransaction(
      "checkout", // name
      "perform-checkout" // operation
  );

  // Set transaction on scope to associate with errors and get included span instrumentation
  // If there's currently an unfinished transaction, it may be dropped
  SentrySdk.ConfigureScope(scope => scope.Transaction = transaction);

  // Validate the cart
  var validationSpan = transaction.StartChild(
      "validation", // operation
      "validating shopping cart" // description
  );

  await ValidateShoppingCartAsync();

  validationSpan.Finish();

  // Process the order
  var processSpan = transaction.StartChild(
      "process", // operation
      "processing shopping cart" // description
  )

  await ProcessShoppingCartAsync();

  processSpan.Finish();

  transaction.Finish();
}

This example will send a transaction checkout to Sentry. The transaction will contain a validation span that measures how long ValidateShoppingCartAsync took and a process span that measures ProcessShoppingCartAsync. Finally, the call to transaction.Finish() will finish the transaction and send it to Sentry.

In cases where you want to attach Spans to an already ongoing Transaction you can use SentrySdk.GetSpan(). If there is a running Transaction or Span currently on the scope, this method will return a SentryTransaction or Span; otherwise, it returns null.

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using Sentry;

var span = SentrySdk.GetSpan();

if (span == null)
{
    span = SentrySdk.StartTransaction("task", "op");
}
else
{
    span = span.StartChild("subtask");
}
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