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// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package middleware
import (
"fmt"
"net/http"
"cloud.google.com/go/errorreporting"
"golang.org/x/pkgsite/internal/config"
"golang.org/x/pkgsite/internal/derrors"
)
// ErrorReporting returns a middleware that reports any server errors using the
// report func.
func ErrorReporting(report func(errorreporting.Entry)) Middleware {
return func(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w2 := &erResponseWriter{ResponseWriter: w}
h.ServeHTTP(w2, r)
// Don't report if the bypass header was set.
if w2.bypass {
return
}
// Don't report success or client errors.
if w2.status < 500 {
return
}
// Don't report 503s; they are a normal consequence of load shedding.
if w2.status == http.StatusServiceUnavailable {
return
}
// Don't report errors where the proxy times out; they're too common.
if w2.status == derrors.ToStatus(derrors.ProxyTimedOut) {
return
}
// Don't report on proxy internal errors; they're not actionable.
if w2.status == derrors.ToStatus(derrors.ProxyError) {
return
}
// Don't report on vulndb errors.
if w2.status == derrors.ToStatus(derrors.VulnDBError) {
return
}
report(errorreporting.Entry{
Error: fmt.Errorf("handler for %q returned status code %d", r.URL.Path, w2.status),
Req: r,
})
})
}
}
type erResponseWriter struct {
http.ResponseWriter
bypass bool
status int
}
func (rw *erResponseWriter) WriteHeader(code int) {
rw.status = code
if rw.ResponseWriter.Header().Get(config.BypassErrorReportingHeader) == "true" {
rw.bypass = true
// Don't send this header to clients.
rw.ResponseWriter.Header().Del(config.BypassErrorReportingHeader)
}
rw.ResponseWriter.WriteHeader(code)
}