Go agent v2.3

2.3.0 Notes

• Added support for Echo in the new nrecho package.

  • Documentation
  • Example

• Introduced Transaction.SetWebResponse(http.ResponseWriter) method which sets the transaction's response writer. After calling this method, the Transaction may be used in place of the http.ResponseWriter to intercept the response code. This method is useful when the http.ResponseWriter is not available at the beginning of the transaction (if so, it can be given as a parameter to Application.StartTransaction). This method will return a reference to the transaction which implements the combination of http.CloseNotifier, http.Flusher, http.Hijacker, and io.ReaderFrom implemented by the ResponseWriter. Example:

func setResponseDemo(txn newrelic.Transaction) {
    recorder := httptest.NewRecorder()
    txn = txn.SetWebResponse(recorder)
    txn.WriteHeader(200)
    fmt.Println("response code recorded:", recorder.Code)
}

• The Transaction's http.ResponseWriter methods may now be called safely if a http.ResponseWriter has not been set. This allows you to add a response code to the transaction without using a http.ResponseWriter. Example:

func transactionWithResponseCode(app newrelic.Application) {
       txn := app.StartTransaction("hasResponseCode", nil, nil)
       defer txn.End()
       txn.WriteHeader(200) // Safe!
}

• The agent will now collect environment variables prefixed by NEW_RELIC_METADATA_ and KUBERNETES_SERVICE_HOST. These will be added to Transaction events to provide context between your Kubernetes cluster and your services. For details on the benefits (currently in beta) see this blog post
• The agent now collects the fully qualified domain name of the host and local IP addresses for improved linking with our Infrastructure product.