Files
fn-serverless/vendor/github.com/grpc-ecosystem/go-grpc-middleware/tracing/opentracing/metadata.go
Andrea Rosa e637661ea2 Adding a way to inject a request ID (#1046)
* Adding a way to inject a request ID

It is very useful to associate a request ID to each incoming request,
this change allows to provide a function to do that via Server Option.
The change comes with a default function which will generate a new
request ID. The request ID is put in the request context along with a
common logger which always logs the request-id

We add gRPC interceptors to the server so it can get the request ID out
of the gRPC metadata and put it in the common logger stored in the
context so as all the log lines using the common logger from the context
will have the request ID logged
2018-06-14 10:40:55 +01:00

57 lines
1.5 KiB
Go

// Copyright 2017 Michal Witkowski. All Rights Reserved.
// See LICENSE for licensing terms.
package grpc_opentracing
import (
"encoding/base64"
"strings"
"fmt"
"google.golang.org/grpc/metadata"
)
const (
binHdrSuffix = "-bin"
)
// metadataTextMap extends a metadata.MD to be an opentracing textmap
type metadataTextMap metadata.MD
// Set is a opentracing.TextMapReader interface that extracts values.
func (m metadataTextMap) Set(key, val string) {
// gRPC allows for complex binary values to be written.
encodedKey, encodedVal := encodeKeyValue(key, val)
// The metadata object is a multimap, and previous values may exist, but for opentracing headers, we do not append
// we just override.
m[encodedKey] = []string{encodedVal}
}
// ForeachKey is a opentracing.TextMapReader interface that extracts values.
func (m metadataTextMap) ForeachKey(callback func(key, val string) error) error {
for k, vv := range m {
for _, v := range vv {
if decodedKey, decodedVal, err := metadata.DecodeKeyValue(k, v); err == nil {
if err = callback(decodedKey, decodedVal); err != nil {
return err
}
} else {
return fmt.Errorf("failed decoding opentracing from gRPC metadata: %v", err)
}
}
}
return nil
}
// encodeKeyValue encodes key and value qualified for transmission via gRPC.
// note: copy pasted from private values of grpc.metadata
func encodeKeyValue(k, v string) (string, string) {
k = strings.ToLower(k)
if strings.HasSuffix(k, binHdrSuffix) {
val := base64.StdEncoding.EncodeToString([]byte(v))
v = string(val)
}
return k, v
}