package client import ( "context" "fmt" "net/http" "strconv" "github.com/grafana/dskit/instrument" ) // Requester executes an HTTP request. type Requester interface { Do(req *http.Request) (*http.Response, error) } // TimedClient instruments a request. It implements Requester. type TimedClient struct { client Requester collector instrument.Collector } type contextKey int // OperationNameContextKey specifies the operation name location within the context // for instrumentation. const OperationNameContextKey contextKey = 0 // NewTimedClient creates a Requester that instruments requests on `client`. func NewTimedClient(client Requester, collector instrument.Collector) *TimedClient { return &TimedClient{ client: client, collector: collector, } } // Do executes the request. func (c TimedClient) Do(r *http.Request) (*http.Response, error) { return TimeRequest(r.Context(), c.operationName(r), c.collector, c.client, r) } // RoundTrip implements the RoundTripper interface. func (c TimedClient) RoundTrip(r *http.Request) (*http.Response, error) { return c.Do(r) } func (c TimedClient) operationName(r *http.Request) string { operation, _ := r.Context().Value(OperationNameContextKey).(string) if operation == "" { operation = r.URL.Path } return operation } // TimeRequest performs an HTTP client request and records the duration in a histogram. func TimeRequest(ctx context.Context, operation string, coll instrument.Collector, client Requester, request *http.Request) (*http.Response, error) { var response *http.Response doRequest := func(_ context.Context) error { var err error response, err = client.Do(request) // nolint:bodyclose return err } toStatusCode := func(err error) string { if err == nil { return strconv.Itoa(response.StatusCode) } return "error" } err := instrument.CollectedRequest(ctx, fmt.Sprintf("%s %s", request.Method, operation), coll, toStatusCode, doRequest) return response, err }