metadata: small optimization and export default metadata size

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>
This commit is contained in:
Василий Толстов 2020-10-12 17:17:59 +03:00
parent 62502ad720
commit 0a5b34a07b
2 changed files with 43 additions and 4 deletions

View File

@ -13,6 +13,10 @@ type metadataKey struct{}
// from Transport headers.
type Metadata map[string]string
var (
DefaultMetadataSize = 6
)
func (md Metadata) Get(key string) (string, bool) {
// fast path
val, ok := md[key]
@ -39,6 +43,9 @@ func (md Metadata) Del(key string) {
// Copy makes a copy of the metadata
func Copy(md Metadata) Metadata {
if len(md) == 0 {
return make(Metadata, DefaultMetadataSize)
}
nmd := make(Metadata, len(md))
for key, val := range md {
nmd.Set(key, val)
@ -49,7 +56,7 @@ func Copy(md Metadata) Metadata {
func Del(ctx context.Context, key string) context.Context {
md, ok := FromContext(ctx)
if !ok {
md = make(Metadata)
md = make(Metadata, DefaultMetadataSize)
}
md.Del(key)
return context.WithValue(ctx, metadataKey{}, md)
@ -59,7 +66,7 @@ func Del(ctx context.Context, key string) context.Context {
func Set(ctx context.Context, key, val string) context.Context {
md, ok := FromContext(ctx)
if !ok {
md = make(Metadata)
md = make(Metadata, DefaultMetadataSize)
}
md.Set(key, val)
return context.WithValue(ctx, metadataKey{}, md)
@ -84,9 +91,17 @@ func FromContext(ctx context.Context) (Metadata, bool) {
return nmd, ok
}
// New return new sized metadata
func New(size int) Metadata {
if size == 0 {
size = DefaultMetadataSize
}
return make(Metadata, size)
}
// NewContext creates a new context with the given metadata
func NewContext(ctx context.Context, md Metadata) context.Context {
return context.WithValue(ctx, metadataKey{}, md)
return context.WithValue(ctx, metadataKey{}, Copy(md))
}
// MergeContext merges metadata to existing metadata, overwriting if specified
@ -96,7 +111,7 @@ func MergeContext(ctx context.Context, pmd Metadata, overwrite bool) context.Con
}
md, ok := FromContext(ctx)
if !ok {
md = make(Metadata, len(pmd))
return context.WithValue(ctx, metadataKey{}, Copy(pmd))
}
nmd := Copy(md)
for key, val := range pmd {

View File

@ -6,6 +6,30 @@ import (
"testing"
)
func TestMedataCanonicalKey(t *testing.T) {
ctx := Set(context.TODO(), "x-request-id", "12345")
v, ok := Get(ctx, "x-request-id")
if !ok {
t.Fatalf("failed to get x-request-id")
} else if v != "12345" {
t.Fatalf("invalid metadata value: %s != %s", "12345", v)
}
v, ok = Get(ctx, "X-Request-Id")
if !ok {
t.Fatalf("failed to get x-request-id")
} else if v != "12345" {
t.Fatalf("invalid metadata value: %s != %s", "12345", v)
}
v, ok = Get(ctx, "X-Request-ID")
if !ok {
t.Fatalf("failed to get x-request-id")
} else if v != "12345" {
t.Fatalf("invalid metadata value: %s != %s", "12345", v)
}
}
func TestMetadataSet(t *testing.T) {
ctx := Set(context.TODO(), "Key", "val")