Function NewHTTPMiddleware

src/libraries/go/lib/pkg/core/httpservice.go:346–385

HTTPMiddleware builds a http middleware that: - Adds contexted request logger with {method,path,ip} into request.Context - Collects _http_duration_seconds metrics with {path,method} dimensions, if latencyMetricsName is specified - Wraps handler with http.TimeoutHandler with `h

(ctx context.Context, opts ...HTTPMiddlewareOption)

//   - Collects <latencyMetricsName>_http_duration_seconds metrics with
//     {path,method} dimensions, if latencyMetricsName is specified
//
// - Wraps handler with http.TimeoutHandler with `handlerTimeout`.
//
// - Wraps request.Body with MaxBytesReader with `requestBodyLimit`.
//
//   - Instruments OpenTelemetry by adding a span to the request context
//     that tracks the response and its return codes
func NewHTTPMiddleware(ctx context.Context, opts ...HTTPMiddlewareOption) []mux.MiddlewareFunc {
	m := &httpMiddleware{
		handlerTimeout:       5 * time.Second,
		requestBodyLimit:     int64(1 << 20), // 1 MB
		prometheusRegisterer: prometheus.DefaultRegisterer,
		telemetryExcludedRoutes: map[string]interface{}{
			// Exclude /healthz
			httpHealthRoutePath: nil,
		},
	}

	// Apply options
	for _, o := range opts {
		o(m)
	}

	var mw []mux.MiddlewareFunc

	// Add telemetry middleware if enabled
	if m.telemetryServiceName != "" {
		mw = append(mw, telemetryMiddleware(m.telemetryServiceName, m.telemetryExcludedRoutes))
		if len(m.telemetryAttributes) > 0 {
			mw = append(mw, telemetryAttributesMiddleware(m.telemetryAttributes))
		}
	}

	mw = append(mw, loggingMiddleware(ctx), metricsMiddleware(m.latencyMetricsName, m.prometheusRegisterer))

	// Add timeout middleware
	if m.handlerTimeout > 0 {
		mw = append(mw, timeoutMiddleware(m.handlerTimeout))
	}

	// Add max request body middleware
	if m.requestBodyLimit > 0 {
		mw = append(mw, maxRequestBodyMiddleware(m.requestBodyLimit))