mirror of
https://github.com/1f349/violet.git
synced 2024-11-22 03:11:44 +00:00
119 lines
3.6 KiB
Go
119 lines
3.6 KiB
Go
package metrics
|
|
|
|
import (
|
|
"context"
|
|
"github.com/prometheus/client_golang/prometheus"
|
|
"github.com/prometheus/client_golang/prometheus/promauto"
|
|
"github.com/prometheus/client_golang/prometheus/promhttp"
|
|
"net/http"
|
|
)
|
|
|
|
// Copyright 2022 The Prometheus Authors
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
// Package metrics is adapted from
|
|
// https://github.com/bwplotka/correlator/tree/main/examples/observability/ping/pkg/httpinstrumentation
|
|
// https://github.com/prometheus/client_golang/blob/main/examples/middleware/httpmiddleware/httpmiddleware.go
|
|
|
|
type Middleware interface {
|
|
// WrapHandler wraps the given HTTP handler for instrumentation.
|
|
WrapHandler(handlerName string, handler http.Handler) http.HandlerFunc
|
|
}
|
|
|
|
type middleware struct {
|
|
buckets []float64
|
|
registry prometheus.Registerer
|
|
}
|
|
|
|
// WrapHandler wraps the given HTTP handler for instrumentation:
|
|
// It registers four metric collectors (if not already done) and reports HTTP
|
|
// metrics to the (newly or already) registered collectors.
|
|
// Each has a constant label named "handler" with the provided handlerName as
|
|
// value.
|
|
func (m *middleware) WrapHandler(handlerName string, handler http.Handler) http.HandlerFunc {
|
|
reg := prometheus.WrapRegistererWith(prometheus.Labels{"handler": handlerName}, m.registry)
|
|
|
|
requestsTotal := promauto.With(reg).NewCounterVec(
|
|
prometheus.CounterOpts{
|
|
Name: "http_requests_total",
|
|
Help: "Tracks the number of HTTP requests.",
|
|
}, []string{"method", "code", "host"},
|
|
)
|
|
requestDuration := promauto.With(reg).NewHistogramVec(
|
|
prometheus.HistogramOpts{
|
|
Name: "http_request_duration_seconds",
|
|
Help: "Tracks the latencies for HTTP requests.",
|
|
Buckets: m.buckets,
|
|
},
|
|
[]string{"method", "code", "host"},
|
|
)
|
|
requestSize := promauto.With(reg).NewSummaryVec(
|
|
prometheus.SummaryOpts{
|
|
Name: "http_request_size_bytes",
|
|
Help: "Tracks the size of HTTP requests.",
|
|
},
|
|
[]string{"method", "code", "host"},
|
|
)
|
|
responseSize := promauto.With(reg).NewSummaryVec(
|
|
prometheus.SummaryOpts{
|
|
Name: "http_response_size_bytes",
|
|
Help: "Tracks the size of HTTP responses.",
|
|
},
|
|
[]string{"method", "code", "host"},
|
|
)
|
|
|
|
hostCtxGetter := promhttp.WithLabelFromCtx("host", func(ctx context.Context) string {
|
|
s, _ := ctx.Value(hostCtxKey(0)).(string)
|
|
return s
|
|
})
|
|
|
|
// Wraps the provided http.Handler to observe the request result with the provided metrics.
|
|
base := promhttp.InstrumentHandlerCounter(
|
|
requestsTotal,
|
|
promhttp.InstrumentHandlerDuration(
|
|
requestDuration,
|
|
promhttp.InstrumentHandlerRequestSize(
|
|
requestSize,
|
|
promhttp.InstrumentHandlerResponseSize(
|
|
responseSize,
|
|
handler,
|
|
hostCtxGetter,
|
|
),
|
|
hostCtxGetter,
|
|
),
|
|
hostCtxGetter,
|
|
),
|
|
hostCtxGetter,
|
|
)
|
|
|
|
return base.ServeHTTP
|
|
}
|
|
|
|
// New returns a Middleware interface.
|
|
func New(registry prometheus.Registerer, buckets []float64) Middleware {
|
|
if buckets == nil {
|
|
buckets = prometheus.ExponentialBuckets(0.1, 1.5, 5)
|
|
}
|
|
|
|
return &middleware{
|
|
buckets: buckets,
|
|
registry: registry,
|
|
}
|
|
}
|
|
|
|
type hostCtxKey uint8
|
|
|
|
func AddHostCtx(req *http.Request) *http.Request {
|
|
return req.WithContext(context.WithValue(req.Context(), hostCtxKey(0), req.Host))
|
|
}
|