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package otgrpc
import (
"strings"
opentracing "github.com/opentracing/opentracing-go"
"github.com/opentracing/opentracing-go/ext"
"google.golang.org/grpc/metadata"
)
var (
// Morally a const:
gRPCComponentTag = opentracing.Tag{string(ext.Component), "gRPC"}
)
// metadataReaderWriter satisfies both the opentracing.TextMapReader and
// opentracing.TextMapWriter interfaces.
type metadataReaderWriter struct {
metadata.MD
}
func (w metadataReaderWriter) Set(key, val string) {
// The GRPC HPACK implementation rejects any uppercase keys here.
//
// As such, since the HTTP_HEADERS format is case-insensitive anyway, we
// blindly lowercase the key (which is guaranteed to work in the
// Inject/Extract sense per the OpenTracing spec).
key = strings.ToLower(key)
w.MD[key] = append(w.MD[key], val)
}
func (w metadataReaderWriter) ForeachKey(handler func(key, val string) error) error {
for k, vals := range w.MD {
for _, v := range vals {
if err := handler(k, v); err != nil {
return err
}
}
}
return nil
}
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