48 lines
1017 B
Go
48 lines
1017 B
Go
// Package metadata is a way of defining message headers
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package metadata
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import (
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"context"
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)
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type metaKey struct{}
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// Metadata is our way of representing request headers internally.
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// They're used at the RPC level and translate back and forth
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// from Transport headers.
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type Metadata map[string]string
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func Copy(md Metadata) Metadata {
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cmd := make(Metadata)
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for k, v := range md {
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cmd[k] = v
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}
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return cmd
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}
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func FromContext(ctx context.Context) (Metadata, bool) {
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md, ok := ctx.Value(metaKey{}).(Metadata)
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return md, ok
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}
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func NewContext(ctx context.Context, md Metadata) context.Context {
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return context.WithValue(ctx, metaKey{}, md)
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}
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func AppendContext(ctx context.Context, patchMd Metadata, overwrite bool) context.Context {
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md, _ := ctx.Value(metaKey{}).(Metadata)
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cmd := make(Metadata)
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for k, v := range md {
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cmd[k] = v
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}
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for k, v := range patchMd {
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if _, ok := cmd[k]; ok && !overwrite {
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// skip
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} else {
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cmd[k] = v
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}
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}
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return context.WithValue(ctx, metaKey{}, cmd)
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}
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