108 lines
2.6 KiB
Go
108 lines
2.6 KiB
Go
/*
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Copyright The containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package ttrpc
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import (
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"context"
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"strings"
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)
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// MD is the user type for ttrpc metadata
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type MD map[string][]string
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// Get returns the metadata for a given key when they exist.
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// If there is no metadata, a nil slice and false are returned.
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func (m MD) Get(key string) ([]string, bool) {
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key = strings.ToLower(key)
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list, ok := m[key]
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if !ok || len(list) == 0 {
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return nil, false
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}
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return list, true
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}
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// Set sets the provided values for a given key.
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// The values will overwrite any existing values.
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// If no values provided, a key will be deleted.
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func (m MD) Set(key string, values ...string) {
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key = strings.ToLower(key)
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if len(values) == 0 {
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delete(m, key)
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return
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}
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m[key] = values
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}
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// Append appends additional values to the given key.
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func (m MD) Append(key string, values ...string) {
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key = strings.ToLower(key)
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if len(values) == 0 {
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return
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}
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current, ok := m[key]
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if ok {
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m.Set(key, append(current, values...)...)
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} else {
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m.Set(key, values...)
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}
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}
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func (m MD) setRequest(r *Request) {
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for k, values := range m {
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for _, v := range values {
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r.Metadata = append(r.Metadata, &KeyValue{
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Key: k,
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Value: v,
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})
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}
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}
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}
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func (m MD) fromRequest(r *Request) {
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for _, kv := range r.Metadata {
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m[kv.Key] = append(m[kv.Key], kv.Value)
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}
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}
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type metadataKey struct{}
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// GetMetadata retrieves metadata from context.Context (previously attached with WithMetadata)
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func GetMetadata(ctx context.Context) (MD, bool) {
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metadata, ok := ctx.Value(metadataKey{}).(MD)
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return metadata, ok
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}
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// GetMetadataValue gets a specific metadata value by name from context.Context
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func GetMetadataValue(ctx context.Context, name string) (string, bool) {
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metadata, ok := GetMetadata(ctx)
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if !ok {
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return "", false
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}
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if list, ok := metadata.Get(name); ok {
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return list[0], true
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}
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return "", false
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}
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// WithMetadata attaches metadata map to a context.Context
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func WithMetadata(ctx context.Context, md MD) context.Context {
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return context.WithValue(ctx, metadataKey{}, md)
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}
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