140 lines
3.5 KiB
Go
140 lines
3.5 KiB
Go
package recovery
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import (
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"bufio"
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"context"
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"fmt"
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"net"
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"net/http"
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"runtime"
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"github.com/traefik/traefik/v3/pkg/middlewares"
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)
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const (
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typeName = "Recovery"
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middlewareName = "traefik-internal-recovery"
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)
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type recovery struct {
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next http.Handler
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}
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// New creates recovery middleware.
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func New(ctx context.Context, next http.Handler) (http.Handler, error) {
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middlewares.GetLogger(ctx, middlewareName, typeName).Debug().Msg("Creating middleware")
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return &recovery{
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next: next,
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}, nil
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}
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func (re *recovery) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
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recoveryRW := newRecoveryResponseWriter(rw)
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defer recoverFunc(recoveryRW, req)
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re.next.ServeHTTP(recoveryRW, req)
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}
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func recoverFunc(rw recoveryResponseWriter, req *http.Request) {
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if err := recover(); err != nil {
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defer rw.finalizeResponse()
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logger := middlewares.GetLogger(req.Context(), middlewareName, typeName)
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if !shouldLogPanic(err) {
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logger.Debug().Msgf("Request has been aborted [%s - %s]: %v", req.RemoteAddr, req.URL, err)
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return
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}
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logger.Error().Msgf("Recovered from panic in HTTP handler [%s - %s]: %+v", req.RemoteAddr, req.URL, err)
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const size = 64 << 10
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buf := make([]byte, size)
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buf = buf[:runtime.Stack(buf, false)]
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logger.Error().Msgf("Stack: %s", buf)
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}
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}
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// https://github.com/golang/go/blob/a0d6420d8be2ae7164797051ec74fa2a2df466a1/src/net/http/server.go#L1761-L1775
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// https://github.com/golang/go/blob/c33153f7b416c03983324b3e8f869ce1116d84bc/src/net/http/httputil/reverseproxy.go#L284
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func shouldLogPanic(panicValue interface{}) bool {
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//nolint:errorlint // false-positive because panicValue is an interface.
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return panicValue != nil && panicValue != http.ErrAbortHandler
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}
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type recoveryResponseWriter interface {
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http.ResponseWriter
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finalizeResponse()
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}
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func newRecoveryResponseWriter(rw http.ResponseWriter) recoveryResponseWriter {
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wrapper := &responseWriterWrapper{rw: rw}
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if _, ok := rw.(http.CloseNotifier); !ok {
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return wrapper
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}
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return &responseWriterWrapperWithCloseNotify{wrapper}
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}
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type responseWriterWrapper struct {
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rw http.ResponseWriter
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headersSent bool
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}
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func (r *responseWriterWrapper) Header() http.Header {
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return r.rw.Header()
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}
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func (r *responseWriterWrapper) Write(bytes []byte) (int, error) {
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r.headersSent = true
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return r.rw.Write(bytes)
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}
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func (r *responseWriterWrapper) WriteHeader(code int) {
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if r.headersSent {
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return
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}
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// Handling informational headers.
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if code >= 100 && code <= 199 {
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r.rw.WriteHeader(code)
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return
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}
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r.headersSent = true
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r.rw.WriteHeader(code)
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}
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func (r *responseWriterWrapper) Flush() {
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if f, ok := r.rw.(http.Flusher); ok {
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f.Flush()
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}
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}
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func (r *responseWriterWrapper) Hijack() (net.Conn, *bufio.ReadWriter, error) {
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if h, ok := r.rw.(http.Hijacker); ok {
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return h.Hijack()
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}
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return nil, nil, fmt.Errorf("not a hijacker: %T", r.rw)
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}
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func (r *responseWriterWrapper) finalizeResponse() {
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// If headers have been sent this is not possible to respond with an HTTP error,
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// and we let the server abort the response silently thanks to the http.ErrAbortHandler sentinel panic value.
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if r.headersSent {
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panic(http.ErrAbortHandler)
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}
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// The response has not yet started to be written,
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// we can safely return a fresh new error response.
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http.Error(r.rw, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
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}
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type responseWriterWrapperWithCloseNotify struct {
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*responseWriterWrapper
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}
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func (r *responseWriterWrapperWithCloseNotify) CloseNotify() <-chan bool {
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return r.rw.(http.CloseNotifier).CloseNotify()
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}
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