// InstrumentHandlerFuncWithOpts works like InstrumentHandlerFunc but provides
// more flexibility (at the cost of a more complex call syntax).
//
// As InstrumentHandlerFunc, this function registers four metric collectors, but it
// uses the provided SummaryOpts to create them. However, the fields "Name" and
// "Help" in the SummaryOpts are ignored. "Name" is replaced by
// "requests_total", "request_duration_microseconds", "request_size_bytes", and
// "response_size_bytes", respectively. "Help" is replaced by an appropriate
// help string. The names of the variable labels of the http_requests_total
// CounterVec are "method" (get, post, etc.), and "code" (HTTP status code).
//
// If InstrumentHandlerWithOpts is called as follows, it mimics exactly the
// behavior of InstrumentHandler:
//
// prometheus.InstrumentHandlerWithOpts(
// prometheus.SummaryOpts{
// Subsystem: "http",
// ConstLabels: prometheus.Labels{"handler": handlerName},
// },
// handler,
// )
//
// Technical detail: "requests_total" is a CounterVec, not a SummaryVec, so it
// cannot use SummaryOpts. Instead, a CounterOpts struct is created internally,
// and all its fields are set to the equally named fields in the provided
// SummaryOpts.
func InstrumentHandlerFuncWithOpts(opts prometheus.SummaryOpts, handlerFunc gin.HandlerFunc) gin.HandlerFunc {
reqCnt := prometheus.NewCounterVec(
prometheus.CounterOpts{
Namespace: opts.Namespace,
Subsystem: opts.Subsystem,
Name: "requests_total",
Help: "Total number of HTTP requests made.",
ConstLabels: opts.ConstLabels,
},
instLabels,
)
opts.Name = "request_duration_microseconds"
opts.Help = "The HTTP request latencies in microseconds."
reqDur := prometheus.NewSummary(opts)
opts.Name = "request_size_bytes"
opts.Help = "The HTTP request sizes in bytes."
reqSz := prometheus.NewSummary(opts)
opts.Name = "response_size_bytes"
opts.Help = "The HTTP response sizes in bytes."
resSz := prometheus.NewSummary(opts)
regReqCnt := prometheus.MustRegisterOrGet(reqCnt).(*prometheus.CounterVec)
regReqDur := prometheus.MustRegisterOrGet(reqDur).(prometheus.Summary)
regReqSz := prometheus.MustRegisterOrGet(reqSz).(prometheus.Summary)
regResSz := prometheus.MustRegisterOrGet(resSz).(prometheus.Summary)
return func(c *gin.Context) {
now := time.Now()
r := c.Request
out := make(chan int)
urlLen := 0
if r.URL != nil {
urlLen = len(r.URL.String())
}
go computeApproximateRequestSize(r, out, urlLen)
handlerFunc(c)
elapsed := float64(time.Since(now)) / float64(time.Microsecond)
method := sanitizeMethod(r.Method)
code := sanitizeCode(c.Writer.Status())
regReqCnt.WithLabelValues(method, code).Inc()
regReqDur.Observe(elapsed)
regResSz.Observe(float64(c.Writer.Size()))
regReqSz.Observe(float64(<-out))
}
}
// InstrumentRouteFunc works like Prometheus' InstrumentHandlerFunc but wraps
// the go-restful RouteFunction instead of a HandlerFunc
func InstrumentRouteFunc(handlerName string, routeFunc restful.RouteFunction) restful.RouteFunction {
opts := prometheus.SummaryOpts{
Subsystem: "http",
ConstLabels: prometheus.Labels{"handler": handlerName},
}
reqCnt := prometheus.NewCounterVec(
prometheus.CounterOpts{
Subsystem: opts.Subsystem,
Name: "requests_total",
Help: "Total number of HTTP requests made.",
ConstLabels: opts.ConstLabels,
},
instLabels,
)
opts.Name = "request_duration_microseconds"
opts.Help = "The HTTP request latencies in microseconds."
reqDur := prometheus.NewSummary(opts)
opts.Name = "request_size_bytes"
opts.Help = "The HTTP request sizes in bytes."
reqSz := prometheus.NewSummary(opts)
opts.Name = "response_size_bytes"
opts.Help = "The HTTP response sizes in bytes."
resSz := prometheus.NewSummary(opts)
regReqCnt := prometheus.MustRegisterOrGet(reqCnt).(*prometheus.CounterVec)
regReqDur := prometheus.MustRegisterOrGet(reqDur).(prometheus.Summary)
regReqSz := prometheus.MustRegisterOrGet(reqSz).(prometheus.Summary)
regResSz := prometheus.MustRegisterOrGet(resSz).(prometheus.Summary)
return restful.RouteFunction(func(request *restful.Request, response *restful.Response) {
now := time.Now()
delegate := &responseWriterDelegator{ResponseWriter: response.ResponseWriter}
out := make(chan int)
urlLen := 0
if request.Request.URL != nil {
urlLen = len(request.Request.URL.String())
}
go computeApproximateRequestSize(request.Request, out, urlLen)
_, cn := response.ResponseWriter.(http.CloseNotifier)
_, fl := response.ResponseWriter.(http.Flusher)
_, hj := response.ResponseWriter.(http.Hijacker)
_, rf := response.ResponseWriter.(io.ReaderFrom)
var rw http.ResponseWriter
if cn && fl && hj && rf {
rw = &fancyResponseWriterDelegator{delegate}
} else {
rw = delegate
}
response.ResponseWriter = rw
routeFunc(request, response)
elapsed := float64(time.Since(now)) / float64(time.Microsecond)
method := strings.ToLower(request.Request.Method)
code := strconv.Itoa(delegate.status)
regReqCnt.WithLabelValues(method, code).Inc()
regReqDur.Observe(elapsed)
regResSz.Observe(float64(delegate.written))
regReqSz.Observe(float64(<-out))
})
}