a412255ad1
Add prometheus metrics to the cache handler. This just used prometheus, if the metrics middleware does not setup the handler, there is nobody reading these metrics, but they are still reported. Seems the simplest solution while keeping the whole middleware separation in tact.
115 lines
4.1 KiB
Go
115 lines
4.1 KiB
Go
// Package middleware provides some types and functions common among middleware.
|
|
package middleware
|
|
|
|
import (
|
|
"time"
|
|
|
|
"github.com/miekg/dns"
|
|
"golang.org/x/net/context"
|
|
)
|
|
|
|
type (
|
|
// Middleware is the middle layer which represents the traditional
|
|
// idea of middleware: it chains one Handler to the next by being
|
|
// passed the next Handler in the chain.
|
|
Middleware func(Handler) Handler
|
|
|
|
// Handler is like dns.Handler except ServeDNS may return an rcode
|
|
// and/or error.
|
|
//
|
|
// If ServeDNS writes to the response body, it should return a status
|
|
// code. If the status code is not one of the following:
|
|
// * SERVFAIL (dns.RcodeServerFailure)
|
|
// * REFUSED (dns.RecodeRefused)
|
|
// * FORMERR (dns.RcodeFormatError)
|
|
// * NOTIMP (dns.RcodeNotImplemented)
|
|
//
|
|
// CoreDNS assumes *no* reply has yet been written. All other response
|
|
// codes signal other handlers above it that the response message is
|
|
// already written, and that they should not write to it also.
|
|
//
|
|
// If ServeDNS encounters an error, it should return the error value
|
|
// so it can be logged by designated error-handling middleware.
|
|
//
|
|
// If writing a response after calling another ServeDNS method, the
|
|
// returned rcode SHOULD be used when writing the response.
|
|
//
|
|
// If handling errors after calling another ServeDNS method, the
|
|
// returned error value SHOULD be logged or handled accordingly.
|
|
//
|
|
// Otherwise, return values should be propagated down the middleware
|
|
// chain by returning them unchanged.
|
|
Handler interface {
|
|
ServeDNS(context.Context, dns.ResponseWriter, *dns.Msg) (int, error)
|
|
}
|
|
|
|
// HandlerFunc is a convenience type like dns.HandlerFunc, except
|
|
// ServeDNS returns an rcode and an error. See Handler
|
|
// documentation for more information.
|
|
HandlerFunc func(context.Context, dns.ResponseWriter, *dns.Msg) (int, error)
|
|
)
|
|
|
|
// ServeDNS implements the Handler interface.
|
|
func (f HandlerFunc) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
|
|
return f(ctx, w, r)
|
|
}
|
|
|
|
const Namespace = "coredns"
|
|
|
|
// IndexFile looks for a file in /root/fpath/indexFile for each string
|
|
// in indexFiles. If an index file is found, it returns the root-relative
|
|
// path to the file and true. If no index file is found, empty string
|
|
// and false is returned. fpath must end in a forward slash '/'
|
|
// otherwise no index files will be tried (directory paths must end
|
|
// in a forward slash according to HTTP).
|
|
//
|
|
// All paths passed into and returned from this function use '/' as the
|
|
// path separator, just like URLs. IndexFle handles path manipulation
|
|
// internally for systems that use different path separators.
|
|
/*
|
|
func IndexFile(root http.FileSystem, fpath string, indexFiles []string) (string, bool) {
|
|
if fpath[len(fpath)-1] != '/' || root == nil {
|
|
return "", false
|
|
}
|
|
for _, indexFile := range indexFiles {
|
|
// func (http.FileSystem).Open wants all paths separated by "/",
|
|
// regardless of operating system convention, so use
|
|
// path.Join instead of filepath.Join
|
|
fp := path.Join(fpath, indexFile)
|
|
f, err := root.Open(fp)
|
|
if err == nil {
|
|
f.Close()
|
|
return fp, true
|
|
}
|
|
}
|
|
return "", false
|
|
}
|
|
|
|
// SetLastModifiedHeader checks if the provided modTime is valid and if it is sets it
|
|
// as a Last-Modified header to the ResponseWriter. If the modTime is in the future
|
|
// the current time is used instead.
|
|
func SetLastModifiedHeader(w http.ResponseWriter, modTime time.Time) {
|
|
if modTime.IsZero() || modTime.Equal(time.Unix(0, 0)) {
|
|
// the time does not appear to be valid. Don't put it in the response
|
|
return
|
|
}
|
|
|
|
// RFC 2616 - Section 14.29 - Last-Modified:
|
|
// An origin server MUST NOT send a Last-Modified date which is later than the
|
|
// server's time of message origination. In such cases, where the resource's last
|
|
// modification would indicate some time in the future, the server MUST replace
|
|
// that date with the message origination date.
|
|
now := currentTime()
|
|
if modTime.After(now) {
|
|
modTime = now
|
|
}
|
|
|
|
w.Header().Set("Last-Modified", modTime.UTC().Format(http.TimeFormat))
|
|
}
|
|
*/
|
|
|
|
// currentTime, as it is defined here, returns time.Now().
|
|
// It's defined as a variable for mocking time in tests.
|
|
var currentTime = func() time.Time {
|
|
return time.Now()
|
|
}
|