Mortar is a GO framework/library for building gRPC (and REST) web services. Mortar has out-of-the-box support for configuration, application metrics, logging, tracing, profiling, dependency injection and more. While it comes with predefined defaults Mortar gives you total control to fully customize it.


Clone this demo repository and play around.

When you done, read the documentation or create your own service with this template here.


Telemetry (Everything connected)

  • Logs have Tracing Information traceId=6ff7e7e38d1e86f across services

  • Also visible in Jaeger traceId=6ff7e7e38d1e86f if it's sampled.


Support for *http.Client Interceptors, so you can

  • Add request and response info to Trace traceId=6ff7e7e38d1e86f


  • Log/Dump requests and/or responses when http request fails.

    return func(req *http.Request, handler client.HTTPHandler) (resp *http.Response, err error) {
        var reqBytes, respBytes []byte
        // If the response is Bad Request, log both Request and Response
        reqBytes, _ = httputil.DumpRequestOut(req, true) // it can be nil and it's ok
        if resp, err = handler(req); err == nil && resp.StatusCode >= http.StatusBadRequest {
            respBytes, _ = httputil.DumpResponse(resp, true) // it can be nil
            logger.WithError(fmt.Errorf("http request failed")).
            Warn(req.Context(), "\nRequest:\n%s\n\nResponse:\n%s\n", reqBytes, respBytes)


  • Alter requests and/or responses (useful in Tests)

    func(*http.Request, clientInt.HTTPHandler) (*http.Response, error) {
        // special case, don't go anywhere just return the response
        return &http.Response{
            Status:        "200 OK",
            StatusCode:    200,
            Proto:         "HTTP/1.1",
            ProtoMajor:    1,
            ProtoMinor:    1,
            ContentLength: 11,
            Body:          ioutil.NopCloser(strings.NewReader("car painted")),
        }, nil

Monitoring/Metrics support

Export to either Prometheus/Datadog/statsd/etc, it's your choice. Mortar only provides the Interface and also caches the metrics so you don't have to.

counter := w.deps.Metrics.WithTags(monitor.Tags{
 "color":   request.GetDesiredColor(),
 "success": fmt.Sprintf("%t", err == nil),
}).Counter("paint_desired_color", "New paint color for car")


counter is actually a singleton, uniqueness calculated here


For more information about Mortar Monitoring read here.

Additional Features

  • /debug/pprof and other useful handlers
  • Use config_test.yml during tests to override values in config.yml, it saves time.

There are some features not listed here, please check the Documentation for more.