oidc-demo-app/handlers/observability.go

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/*
Copyright 2020, 2021 Jan Dittberner
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 handlers
import (
"context"
"net/http"
"sync/atomic"
log "github.com/sirupsen/logrus"
)
type key int
const (
requestIdKey key = iota
)
type statusCodeInterceptor struct {
http.ResponseWriter
code int
count int
}
func (sci *statusCodeInterceptor) WriteHeader(code int) {
sci.code = code
sci.ResponseWriter.WriteHeader(code)
}
func (sci *statusCodeInterceptor) Write(content []byte) (int, error) {
count, err := sci.ResponseWriter.Write(content)
sci.count += count
return count, err
}
func Logging(logger *log.Logger) func(http.Handler) http.Handler {
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
interceptor := &statusCodeInterceptor{w, http.StatusOK, 0}
defer func() {
requestId, ok := r.Context().Value(requestIdKey).(string)
if !ok {
requestId = "unknown"
}
logger.Infof(
"%s %s \"%s %s\" %d %d \"%s\"",
requestId,
r.RemoteAddr,
r.Method,
r.URL.Path,
interceptor.code,
interceptor.count,
r.UserAgent(),
)
}()
next.ServeHTTP(interceptor, r)
})
}
}
func Tracing(nextRequestId func() string) func(http.Handler) http.Handler {
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
requestId := r.Header.Get("X-Request-Id")
if requestId == "" {
requestId = nextRequestId()
}
ctx := context.WithValue(r.Context(), requestIdKey, requestId)
w.Header().Set("X-Request-Id", requestId)
next.ServeHTTP(w, r.WithContext(ctx))
})
}
}
var Healthy int32
func NewHealthHandler() http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if atomic.LoadInt32(&Healthy) == 1 {
w.WriteHeader(http.StatusNoContent)
return
}
w.WriteHeader(http.StatusServiceUnavailable)
})
}