188 lines
4.9 KiB
Go
188 lines
4.9 KiB
Go
package runtime
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import (
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"fmt"
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"net"
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"net/http"
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"strconv"
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"strings"
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"time"
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"golang.org/x/net/context"
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"google.golang.org/grpc"
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"google.golang.org/grpc/codes"
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"google.golang.org/grpc/grpclog"
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"google.golang.org/grpc/metadata"
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)
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// MetadataHeaderPrefix is the http prefix that represents custom metadata
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// parameters to or from a gRPC call.
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const MetadataHeaderPrefix = "Grpc-Metadata-"
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// MetadataPrefix is the prefix for grpc-gateway supplied custom metadata fields.
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const MetadataPrefix = "grpcgateway-"
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// MetadataTrailerPrefix is prepended to gRPC metadata as it is converted to
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// HTTP headers in a response handled by grpc-gateway
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const MetadataTrailerPrefix = "Grpc-Trailer-"
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const metadataGrpcTimeout = "Grpc-Timeout"
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const xForwardedFor = "X-Forwarded-For"
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const xForwardedHost = "X-Forwarded-Host"
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var (
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// DefaultContextTimeout is used for gRPC call context.WithTimeout whenever a Grpc-Timeout inbound
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// header isn't present. If the value is 0 the sent `context` will not have a timeout.
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DefaultContextTimeout = 0 * time.Second
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)
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/*
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AnnotateContext adds context information such as metadata from the request.
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At a minimum, the RemoteAddr is included in the fashion of "X-Forwarded-For",
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except that the forwarded destination is not another HTTP service but rather
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a gRPC service.
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*/
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func AnnotateContext(ctx context.Context, req *http.Request) (context.Context, error) {
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var pairs []string
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timeout := DefaultContextTimeout
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if tm := req.Header.Get(metadataGrpcTimeout); tm != "" {
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var err error
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timeout, err = timeoutDecode(tm)
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if err != nil {
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return nil, grpc.Errorf(codes.InvalidArgument, "invalid grpc-timeout: %s", tm)
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}
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}
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for key, vals := range req.Header {
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for _, val := range vals {
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// For backwards-compatibility, pass through 'authorization' header with no prefix.
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if strings.ToLower(key) == "authorization" {
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pairs = append(pairs, "authorization", val)
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}
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if isPermanentHTTPHeader(key) {
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pairs = append(pairs, strings.ToLower(fmt.Sprintf("%s%s", MetadataPrefix, key)), val)
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continue
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}
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if strings.HasPrefix(key, MetadataHeaderPrefix) {
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pairs = append(pairs, key[len(MetadataHeaderPrefix):], val)
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}
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}
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}
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if host := req.Header.Get(xForwardedHost); host != "" {
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pairs = append(pairs, strings.ToLower(xForwardedHost), host)
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} else if req.Host != "" {
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pairs = append(pairs, strings.ToLower(xForwardedHost), req.Host)
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}
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if addr := req.RemoteAddr; addr != "" {
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if remoteIP, _, err := net.SplitHostPort(addr); err == nil {
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if fwd := req.Header.Get(xForwardedFor); fwd == "" {
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pairs = append(pairs, strings.ToLower(xForwardedFor), remoteIP)
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} else {
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pairs = append(pairs, strings.ToLower(xForwardedFor), fmt.Sprintf("%s, %s", fwd, remoteIP))
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}
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} else {
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grpclog.Printf("invalid remote addr: %s", addr)
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}
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}
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if timeout != 0 {
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ctx, _ = context.WithTimeout(ctx, timeout)
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}
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if len(pairs) == 0 {
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return ctx, nil
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}
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return metadata.NewContext(ctx, metadata.Pairs(pairs...)), nil
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}
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// ServerMetadata consists of metadata sent from gRPC server.
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type ServerMetadata struct {
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HeaderMD metadata.MD
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TrailerMD metadata.MD
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}
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type serverMetadataKey struct{}
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// NewServerMetadataContext creates a new context with ServerMetadata
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func NewServerMetadataContext(ctx context.Context, md ServerMetadata) context.Context {
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return context.WithValue(ctx, serverMetadataKey{}, md)
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}
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// ServerMetadataFromContext returns the ServerMetadata in ctx
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func ServerMetadataFromContext(ctx context.Context) (md ServerMetadata, ok bool) {
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md, ok = ctx.Value(serverMetadataKey{}).(ServerMetadata)
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return
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}
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func timeoutDecode(s string) (time.Duration, error) {
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size := len(s)
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if size < 2 {
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return 0, fmt.Errorf("timeout string is too short: %q", s)
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}
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d, ok := timeoutUnitToDuration(s[size-1])
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if !ok {
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return 0, fmt.Errorf("timeout unit is not recognized: %q", s)
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}
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t, err := strconv.ParseInt(s[:size-1], 10, 64)
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if err != nil {
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return 0, err
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}
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return d * time.Duration(t), nil
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}
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func timeoutUnitToDuration(u uint8) (d time.Duration, ok bool) {
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switch u {
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case 'H':
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return time.Hour, true
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case 'M':
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return time.Minute, true
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case 'S':
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return time.Second, true
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case 'm':
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return time.Millisecond, true
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case 'u':
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return time.Microsecond, true
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case 'n':
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return time.Nanosecond, true
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default:
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}
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return
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}
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// isPermanentHTTPHeader checks whether hdr belongs to the list of
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// permenant request headers maintained by IANA.
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// http://www.iana.org/assignments/message-headers/message-headers.xml
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func isPermanentHTTPHeader(hdr string) bool {
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switch hdr {
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case
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"Accept",
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"Accept-Charset",
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"Accept-Language",
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"Accept-Ranges",
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"Authorization",
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"Cache-Control",
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"Content-Type",
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"Cookie",
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"Date",
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"Expect",
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"From",
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"Host",
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"If-Match",
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"If-Modified-Since",
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"If-None-Match",
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"If-Schedule-Tag-Match",
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"If-Unmodified-Since",
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"Max-Forwards",
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"Origin",
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"Pragma",
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"Referer",
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"User-Agent",
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"Via",
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"Warning":
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return true
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}
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return false
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}
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