mirror of
https://github.com/prometheus/prometheus.git
synced 2024-11-05 05:04:04 -08:00
261 lines
9.6 KiB
Go
261 lines
9.6 KiB
Go
package runtime
|
|
|
|
import (
|
|
"fmt"
|
|
"net/http"
|
|
"net/textproto"
|
|
"strings"
|
|
|
|
"github.com/golang/protobuf/proto"
|
|
"golang.org/x/net/context"
|
|
"google.golang.org/grpc/codes"
|
|
"google.golang.org/grpc/metadata"
|
|
"google.golang.org/grpc/status"
|
|
)
|
|
|
|
// A HandlerFunc handles a specific pair of path pattern and HTTP method.
|
|
type HandlerFunc func(w http.ResponseWriter, r *http.Request, pathParams map[string]string)
|
|
|
|
// ServeMux is a request multiplexer for grpc-gateway.
|
|
// It matches http requests to patterns and invokes the corresponding handler.
|
|
type ServeMux struct {
|
|
// handlers maps HTTP method to a list of handlers.
|
|
handlers map[string][]handler
|
|
forwardResponseOptions []func(context.Context, http.ResponseWriter, proto.Message) error
|
|
marshalers marshalerRegistry
|
|
incomingHeaderMatcher HeaderMatcherFunc
|
|
outgoingHeaderMatcher HeaderMatcherFunc
|
|
metadataAnnotator func(context.Context, *http.Request) metadata.MD
|
|
protoErrorHandler ProtoErrorHandlerFunc
|
|
}
|
|
|
|
// ServeMuxOption is an option that can be given to a ServeMux on construction.
|
|
type ServeMuxOption func(*ServeMux)
|
|
|
|
// WithForwardResponseOption returns a ServeMuxOption representing the forwardResponseOption.
|
|
//
|
|
// forwardResponseOption is an option that will be called on the relevant context.Context,
|
|
// http.ResponseWriter, and proto.Message before every forwarded response.
|
|
//
|
|
// The message may be nil in the case where just a header is being sent.
|
|
func WithForwardResponseOption(forwardResponseOption func(context.Context, http.ResponseWriter, proto.Message) error) ServeMuxOption {
|
|
return func(serveMux *ServeMux) {
|
|
serveMux.forwardResponseOptions = append(serveMux.forwardResponseOptions, forwardResponseOption)
|
|
}
|
|
}
|
|
|
|
// HeaderMatcherFunc checks whether a header key should be forwarded to/from gRPC context.
|
|
type HeaderMatcherFunc func(string) (string, bool)
|
|
|
|
// DefaultHeaderMatcher is used to pass http request headers to/from gRPC context. This adds permanent HTTP header
|
|
// keys (as specified by the IANA) to gRPC context with grpcgateway- prefix. HTTP headers that start with
|
|
// 'Grpc-Metadata-' are mapped to gRPC metadata after removing prefix 'Grpc-Metadata-'.
|
|
func DefaultHeaderMatcher(key string) (string, bool) {
|
|
key = textproto.CanonicalMIMEHeaderKey(key)
|
|
if isPermanentHTTPHeader(key) {
|
|
return MetadataPrefix + key, true
|
|
} else if strings.HasPrefix(key, MetadataHeaderPrefix) {
|
|
return key[len(MetadataHeaderPrefix):], true
|
|
}
|
|
return "", false
|
|
}
|
|
|
|
// WithIncomingHeaderMatcher returns a ServeMuxOption representing a headerMatcher for incoming request to gateway.
|
|
//
|
|
// This matcher will be called with each header in http.Request. If matcher returns true, that header will be
|
|
// passed to gRPC context. To transform the header before passing to gRPC context, matcher should return modified header.
|
|
func WithIncomingHeaderMatcher(fn HeaderMatcherFunc) ServeMuxOption {
|
|
return func(mux *ServeMux) {
|
|
mux.incomingHeaderMatcher = fn
|
|
}
|
|
}
|
|
|
|
// WithOutgoingHeaderMatcher returns a ServeMuxOption representing a headerMatcher for outgoing response from gateway.
|
|
//
|
|
// This matcher will be called with each header in response header metadata. If matcher returns true, that header will be
|
|
// passed to http response returned from gateway. To transform the header before passing to response,
|
|
// matcher should return modified header.
|
|
func WithOutgoingHeaderMatcher(fn HeaderMatcherFunc) ServeMuxOption {
|
|
return func(mux *ServeMux) {
|
|
mux.outgoingHeaderMatcher = fn
|
|
}
|
|
}
|
|
|
|
// WithMetadata returns a ServeMuxOption for passing metadata to a gRPC context.
|
|
//
|
|
// This can be used by services that need to read from http.Request and modify gRPC context. A common use case
|
|
// is reading token from cookie and adding it in gRPC context.
|
|
func WithMetadata(annotator func(context.Context, *http.Request) metadata.MD) ServeMuxOption {
|
|
return func(serveMux *ServeMux) {
|
|
serveMux.metadataAnnotator = annotator
|
|
}
|
|
}
|
|
|
|
// WithProtoErrorHandler returns a ServeMuxOption for passing metadata to a gRPC context.
|
|
//
|
|
// This can be used to handle an error as general proto message defined by gRPC.
|
|
// The response including body and status is not backward compatible with the default error handler.
|
|
// When this option is used, HTTPError and OtherErrorHandler are overwritten on initialization.
|
|
func WithProtoErrorHandler(fn ProtoErrorHandlerFunc) ServeMuxOption {
|
|
return func(serveMux *ServeMux) {
|
|
serveMux.protoErrorHandler = fn
|
|
}
|
|
}
|
|
|
|
// NewServeMux returns a new ServeMux whose internal mapping is empty.
|
|
func NewServeMux(opts ...ServeMuxOption) *ServeMux {
|
|
serveMux := &ServeMux{
|
|
handlers: make(map[string][]handler),
|
|
forwardResponseOptions: make([]func(context.Context, http.ResponseWriter, proto.Message) error, 0),
|
|
marshalers: makeMarshalerMIMERegistry(),
|
|
}
|
|
|
|
for _, opt := range opts {
|
|
opt(serveMux)
|
|
}
|
|
|
|
if serveMux.protoErrorHandler != nil {
|
|
HTTPError = serveMux.protoErrorHandler
|
|
// OtherErrorHandler is no longer used when protoErrorHandler is set.
|
|
// Overwritten by a special error handler to return Unknown.
|
|
OtherErrorHandler = func(w http.ResponseWriter, r *http.Request, _ string, _ int) {
|
|
ctx := context.Background()
|
|
_, outboundMarshaler := MarshalerForRequest(serveMux, r)
|
|
sterr := status.Error(codes.Unknown, "unexpected use of OtherErrorHandler")
|
|
serveMux.protoErrorHandler(ctx, serveMux, outboundMarshaler, w, r, sterr)
|
|
}
|
|
}
|
|
|
|
if serveMux.incomingHeaderMatcher == nil {
|
|
serveMux.incomingHeaderMatcher = DefaultHeaderMatcher
|
|
}
|
|
|
|
if serveMux.outgoingHeaderMatcher == nil {
|
|
serveMux.outgoingHeaderMatcher = func(key string) (string, bool) {
|
|
return fmt.Sprintf("%s%s", MetadataHeaderPrefix, key), true
|
|
}
|
|
}
|
|
|
|
return serveMux
|
|
}
|
|
|
|
// Handle associates "h" to the pair of HTTP method and path pattern.
|
|
func (s *ServeMux) Handle(meth string, pat Pattern, h HandlerFunc) {
|
|
s.handlers[meth] = append(s.handlers[meth], handler{pat: pat, h: h})
|
|
}
|
|
|
|
// ServeHTTP dispatches the request to the first handler whose pattern matches to r.Method and r.Path.
|
|
func (s *ServeMux) ServeHTTP(w http.ResponseWriter, r *http.Request) {
|
|
ctx := r.Context()
|
|
|
|
path := r.URL.Path
|
|
if !strings.HasPrefix(path, "/") {
|
|
if s.protoErrorHandler != nil {
|
|
_, outboundMarshaler := MarshalerForRequest(s, r)
|
|
sterr := status.Error(codes.InvalidArgument, http.StatusText(http.StatusBadRequest))
|
|
s.protoErrorHandler(ctx, s, outboundMarshaler, w, r, sterr)
|
|
} else {
|
|
OtherErrorHandler(w, r, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
|
|
}
|
|
return
|
|
}
|
|
|
|
components := strings.Split(path[1:], "/")
|
|
l := len(components)
|
|
var verb string
|
|
if idx := strings.LastIndex(components[l-1], ":"); idx == 0 {
|
|
if s.protoErrorHandler != nil {
|
|
_, outboundMarshaler := MarshalerForRequest(s, r)
|
|
sterr := status.Error(codes.Unimplemented, http.StatusText(http.StatusNotImplemented))
|
|
s.protoErrorHandler(ctx, s, outboundMarshaler, w, r, sterr)
|
|
} else {
|
|
OtherErrorHandler(w, r, http.StatusText(http.StatusNotFound), http.StatusNotFound)
|
|
}
|
|
return
|
|
} else if idx > 0 {
|
|
c := components[l-1]
|
|
components[l-1], verb = c[:idx], c[idx+1:]
|
|
}
|
|
|
|
if override := r.Header.Get("X-HTTP-Method-Override"); override != "" && isPathLengthFallback(r) {
|
|
r.Method = strings.ToUpper(override)
|
|
if err := r.ParseForm(); err != nil {
|
|
if s.protoErrorHandler != nil {
|
|
_, outboundMarshaler := MarshalerForRequest(s, r)
|
|
sterr := status.Error(codes.InvalidArgument, err.Error())
|
|
s.protoErrorHandler(ctx, s, outboundMarshaler, w, r, sterr)
|
|
} else {
|
|
OtherErrorHandler(w, r, err.Error(), http.StatusBadRequest)
|
|
}
|
|
return
|
|
}
|
|
}
|
|
for _, h := range s.handlers[r.Method] {
|
|
pathParams, err := h.pat.Match(components, verb)
|
|
if err != nil {
|
|
continue
|
|
}
|
|
h.h(w, r, pathParams)
|
|
return
|
|
}
|
|
|
|
// lookup other methods to handle fallback from GET to POST and
|
|
// to determine if it is MethodNotAllowed or NotFound.
|
|
for m, handlers := range s.handlers {
|
|
if m == r.Method {
|
|
continue
|
|
}
|
|
for _, h := range handlers {
|
|
pathParams, err := h.pat.Match(components, verb)
|
|
if err != nil {
|
|
continue
|
|
}
|
|
// X-HTTP-Method-Override is optional. Always allow fallback to POST.
|
|
if isPathLengthFallback(r) {
|
|
if err := r.ParseForm(); err != nil {
|
|
if s.protoErrorHandler != nil {
|
|
_, outboundMarshaler := MarshalerForRequest(s, r)
|
|
sterr := status.Error(codes.InvalidArgument, err.Error())
|
|
s.protoErrorHandler(ctx, s, outboundMarshaler, w, r, sterr)
|
|
} else {
|
|
OtherErrorHandler(w, r, err.Error(), http.StatusBadRequest)
|
|
}
|
|
return
|
|
}
|
|
h.h(w, r, pathParams)
|
|
return
|
|
}
|
|
if s.protoErrorHandler != nil {
|
|
_, outboundMarshaler := MarshalerForRequest(s, r)
|
|
sterr := status.Error(codes.Unimplemented, http.StatusText(http.StatusMethodNotAllowed))
|
|
s.protoErrorHandler(ctx, s, outboundMarshaler, w, r, sterr)
|
|
} else {
|
|
OtherErrorHandler(w, r, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
|
|
}
|
|
return
|
|
}
|
|
}
|
|
|
|
if s.protoErrorHandler != nil {
|
|
_, outboundMarshaler := MarshalerForRequest(s, r)
|
|
sterr := status.Error(codes.Unimplemented, http.StatusText(http.StatusNotImplemented))
|
|
s.protoErrorHandler(ctx, s, outboundMarshaler, w, r, sterr)
|
|
} else {
|
|
OtherErrorHandler(w, r, http.StatusText(http.StatusNotFound), http.StatusNotFound)
|
|
}
|
|
}
|
|
|
|
// GetForwardResponseOptions returns the ForwardResponseOptions associated with this ServeMux.
|
|
func (s *ServeMux) GetForwardResponseOptions() []func(context.Context, http.ResponseWriter, proto.Message) error {
|
|
return s.forwardResponseOptions
|
|
}
|
|
|
|
func isPathLengthFallback(r *http.Request) bool {
|
|
return r.Method == "POST" && r.Header.Get("Content-Type") == "application/x-www-form-urlencoded"
|
|
}
|
|
|
|
type handler struct {
|
|
pat Pattern
|
|
h HandlerFunc
|
|
}
|