Fast and extensible multi-platform HTTP/1-2-3 web server with automatic HTTPS
Mirrored from https://github.com/Slazee/caddy.git
Synced Nov 13, 23:00 UTC
metrics: Enforce smaller set of method labels
Signed-off-by: Dave Henderson <dhenderson@gmail.com>
Dave Henderson committed
Jan 22, 2022 at 19:08 UTC
eb891d46831252c5329218bfbb606727685fea72
3 files changed
+73
-4
metrics.go
+25
-2
@@ -3,7 +3,6 @@ package caddy
3
import (
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"net/http"
5
"strconv"
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- "strings"
6
7
"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/collectors"
@@ -47,7 +46,7 @@ func instrumentHandlerCounter(counter *prometheus.CounterVec, next http.Handler)
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next.ServeHTTP(d, r)
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counter.With(prometheus.Labels{
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"code": sanitizeCode(d.status),
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- "method": strings.ToUpper(r.Method),
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+ "method": sanitizeMethod(r.Method),
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}).Inc()
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})
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}
@@ -76,3 +75,27 @@ func sanitizeCode(s int) string {
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return strconv.Itoa(s)
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}
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}
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+
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+// Only support the list of "regular" HTTP methods, see
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+// https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods
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+var methodMap = map[string]string{
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+ "GET": http.MethodGet, "get": http.MethodGet,
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+ "HEAD": http.MethodHead, "head": http.MethodHead,
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+ "PUT": http.MethodPut, "put": http.MethodPut,
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+ "POST": http.MethodPost, "post": http.MethodPost,
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+ "DELETE": http.MethodDelete, "delete": http.MethodDelete,
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+ "CONNECT": http.MethodConnect, "connect": http.MethodConnect,
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+ "OPTIONS": http.MethodOptions, "options": http.MethodOptions,
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+ "TRACE": http.MethodTrace, "trace": http.MethodTrace,
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+ "PATCH": http.MethodPatch, "patch": http.MethodPatch,
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+}
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+
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+// sanitizeMethod sanitizes the method for use as a metric label. This helps
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+// prevent high cardinality on the method label. The name is always upper case.
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+func sanitizeMethod(m string) string {
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+ if m, ok := methodMap[m]; ok {
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+ return m
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+ }
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+
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+ return "other"
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+}
modules/caddyhttp/metrics.go
+25
-2
@@ -4,7 +4,6 @@ import (
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"context"
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"net/http"
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"strconv"
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- "strings"
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"sync"
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"time"
9
@@ -109,7 +108,7 @@ func newMetricsInstrumentedHandler(handler string, mh MiddlewareHandler) *metric
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func (h *metricsInstrumentedHandler) ServeHTTP(w http.ResponseWriter, r *http.Request, next Handler) error {
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server := serverNameFromContext(r.Context())
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labels := prometheus.Labels{"server": server, "handler": h.handler}
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- method := strings.ToUpper(r.Method)
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+ method := sanitizeMethod(r.Method)
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// the "code" value is set later, but initialized here to eliminate the possibility
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// of a panic
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statusLabels := prometheus.Labels{"server": server, "handler": h.handler, "method": method, "code": ""}
@@ -160,6 +159,30 @@ func sanitizeCode(code int) string {
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return strconv.Itoa(code)
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}
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+// Only support the list of "regular" HTTP methods, see
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+// https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods
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+var methodMap = map[string]string{
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+ "GET": http.MethodGet, "get": http.MethodGet,
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+ "HEAD": http.MethodHead, "head": http.MethodHead,
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+ "PUT": http.MethodPut, "put": http.MethodPut,
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+ "POST": http.MethodPost, "post": http.MethodPost,
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+ "DELETE": http.MethodDelete, "delete": http.MethodDelete,
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+ "CONNECT": http.MethodConnect, "connect": http.MethodConnect,
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+ "OPTIONS": http.MethodOptions, "options": http.MethodOptions,
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+ "TRACE": http.MethodTrace, "trace": http.MethodTrace,
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+ "PATCH": http.MethodPatch, "patch": http.MethodPatch,
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+}
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+
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+// sanitizeMethod sanitizes the method for use as a metric label. This helps
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+// prevent high cardinality on the method label. The name is always upper case.
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+func sanitizeMethod(m string) string {
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+ if m, ok := methodMap[m]; ok {
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+ return m
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+ }
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+
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+ return "other"
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+}
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+
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// taken from https://github.com/prometheus/client_golang/blob/6007b2b5cae01203111de55f753e76d8dac1f529/prometheus/promhttp/instrument_server.go#L298
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func computeApproximateRequestSize(r *http.Request) int {
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s := 0
modules/caddyhttp/metrics_test.go
+23
@@ -5,6 +5,7 @@ import (
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"errors"
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"net/http"
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"net/http/httptest"
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+ "strings"
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"testing"
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"github.com/prometheus/client_golang/prometheus/testutil"
@@ -82,3 +83,25 @@ type middlewareHandlerFunc func(http.ResponseWriter, *http.Request, Handler) err
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func (f middlewareHandlerFunc) ServeHTTP(w http.ResponseWriter, r *http.Request, h Handler) error {
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return f(w, r, h)
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}
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+
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+func TestSanitizeMethod(t *testing.T) {
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+ tests := []struct {
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+ method string
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+ expected string
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+ }{
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+ {method: "get", expected: "GET"},
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+ {method: "POST", expected: "POST"},
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+ {method: "OPTIONS", expected: "OPTIONS"},
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+ {method: "connect", expected: "CONNECT"},
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+ {method: "trace", expected: "TRACE"},
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+ {method: "UNKNOWN", expected: "other"},
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+ {method: strings.Repeat("ohno", 9999), expected: "other"},
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+ }
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+
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+ for _, d := range tests {
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+ actual := sanitizeMethod(d.method)
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+ if actual != d.expected {
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+ t.Errorf("Not same: expected %#v, but got %#v", d.expected, actual)
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+ }
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+ }
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+}