50 lines
1.1 KiB
Go
50 lines
1.1 KiB
Go
// Package metadata is a way of defining message headers
|
|
package metadata
|
|
|
|
import (
|
|
"context"
|
|
)
|
|
|
|
// FromContext returns metadata from the given context
|
|
func FromContext(ctx context.Context) (Metadata, bool) {
|
|
if ctx == nil {
|
|
return nil, false
|
|
}
|
|
md, ok := ctx.Value(metadataKey{}).(Metadata)
|
|
if !ok {
|
|
return nil, ok
|
|
}
|
|
nmd := Copy(md)
|
|
return nmd, ok
|
|
}
|
|
|
|
// NewContext creates a new context with the given metadata
|
|
func NewContext(ctx context.Context, md Metadata) context.Context {
|
|
if ctx == nil {
|
|
ctx = context.Background()
|
|
}
|
|
return context.WithValue(ctx, metadataKey{}, Copy(md))
|
|
}
|
|
|
|
// MergeContext merges metadata to existing metadata, overwriting if specified
|
|
func MergeContext(ctx context.Context, pmd Metadata, overwrite bool) context.Context {
|
|
if ctx == nil {
|
|
ctx = context.Background()
|
|
}
|
|
md, ok := FromContext(ctx)
|
|
if !ok {
|
|
return context.WithValue(ctx, metadataKey{}, Copy(pmd))
|
|
}
|
|
nmd := Copy(md)
|
|
for key, val := range pmd {
|
|
if _, ok := nmd[key]; ok && !overwrite {
|
|
// skip
|
|
} else if val != "" {
|
|
nmd.Set(key, val)
|
|
} else {
|
|
nmd.Del(key)
|
|
}
|
|
}
|
|
return context.WithValue(ctx, metadataKey{}, nmd)
|
|
}
|