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4fa40e22b2
* Rework Scope metrics according to Prometheus conventions. - counters should end with _total - elaborated and added units to help strings - recommended for cache hit/miss metrics: track only the total and the hits and in separate metrics, since the most common query will be "hits / total" - track all times in seconds (base units), which has become the standard recommendation - other small changes There could be more changes that would require more thinking (what dimensions to use, summaries vs. histograms, etc.), but this is probably enough controversial material already :) * Use timeRequestStatus() in sqs_control_router.go.
85 lines
2.4 KiB
Go
85 lines
2.4 KiB
Go
package middleware
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import (
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"net/http"
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"regexp"
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"strconv"
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"strings"
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"time"
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"github.com/gorilla/mux"
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"github.com/prometheus/client_golang/prometheus"
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)
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// Instrument is a Middleware which records timings for every HTTP request
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type Instrument struct {
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RouteMatcher interface {
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Match(*http.Request, *mux.RouteMatch) bool
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}
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Duration *prometheus.SummaryVec
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}
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func isWSHandshakeRequest(req *http.Request) bool {
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return strings.ToLower(req.Header.Get("Upgrade")) == "websocket" &&
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strings.ToLower(req.Header.Get("Connection")) == "upgrade"
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}
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// Wrap implements middleware.Interface
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func (i Instrument) Wrap(next http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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begin := time.Now()
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isWS := strconv.FormatBool(isWSHandshakeRequest(r))
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interceptor := &interceptor{ResponseWriter: w, statusCode: http.StatusOK}
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route := i.getRouteName(r)
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next.ServeHTTP(interceptor, r)
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var (
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status = strconv.Itoa(interceptor.statusCode)
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took = time.Since(begin)
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)
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i.Duration.WithLabelValues(r.Method, route, status, isWS).Observe(took.Seconds())
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})
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}
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// Return a name identifier for ths request. There are three options:
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// 1. The request matches a gorilla mux route, with a name. Use that.
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// 2. The request matches an unamed gorilla mux router. Munge the path
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// template such that templates like '/api/{org}/foo' come out as
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// 'api_org_foo'.
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// 3. The request doesn't match a mux route. Munge the Path in the same
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// manner as (2).
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// We do all this as we do not wish to emit high cardinality labels to
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// prometheus.
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func (i Instrument) getRouteName(r *http.Request) string {
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var routeMatch mux.RouteMatch
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if i.RouteMatcher.Match(r, &routeMatch) {
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if name := routeMatch.Route.GetName(); name != "" {
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return name
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}
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if tmpl, err := routeMatch.Route.GetPathTemplate(); err != nil {
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return MakeLabelValue(tmpl)
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}
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}
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return MakeLabelValue(r.URL.Path)
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}
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var invalidChars = regexp.MustCompile(`[^a-zA-Z0-9]+`)
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// MakeLabelValue converts a Gorilla mux path to a string suitable for use in
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// a Prometheus label value.
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func MakeLabelValue(path string) string {
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// Convert non-alnums to underscores.
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result := invalidChars.ReplaceAllString(path, "_")
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// Trim leading and trailing underscores.
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result = strings.Trim(result, "_")
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// Make it all lowercase
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result = strings.ToLower(result)
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// Special case.
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if result == "" {
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result = "root"
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}
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return result
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}
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