mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
synced 2024-12-26 04:10:08 +01:00
101 lines
3.9 KiB
Go
101 lines
3.9 KiB
Go
// Copyright 2023, Google Inc.
|
|
// All rights reserved.
|
|
//
|
|
// Redistribution and use in source and binary forms, with or without
|
|
// modification, are permitted provided that the following conditions are
|
|
// met:
|
|
//
|
|
// * Redistributions of source code must retain the above copyright
|
|
// notice, this list of conditions and the following disclaimer.
|
|
// * Redistributions in binary form must reproduce the above
|
|
// copyright notice, this list of conditions and the following disclaimer
|
|
// in the documentation and/or other materials provided with the
|
|
// distribution.
|
|
// * Neither the name of Google Inc. nor the names of its
|
|
// contributors may be used to endorse or promote products derived from
|
|
// this software without specific prior written permission.
|
|
//
|
|
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
|
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
|
|
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
|
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
|
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
|
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
// Package callctx provides helpers for storing and retrieving values out of
|
|
// [context.Context]. These values are used by our client libraries in various
|
|
// ways across the stack.
|
|
package callctx
|
|
|
|
import (
|
|
"context"
|
|
"fmt"
|
|
)
|
|
|
|
const (
|
|
// XGoogFieldMaskHeader is the canonical header key for the [System Parameter]
|
|
// that specifies the response read mask. The value(s) for this header
|
|
// must adhere to format described in [fieldmaskpb].
|
|
//
|
|
// [System Parameter]: https://cloud.google.com/apis/docs/system-parameters
|
|
// [fieldmaskpb]: https://google.golang.org/protobuf/types/known/fieldmaskpb
|
|
XGoogFieldMaskHeader = "x-goog-fieldmask"
|
|
|
|
headerKey = contextKey("header")
|
|
)
|
|
|
|
// contextKey is a private type used to store/retrieve context values.
|
|
type contextKey string
|
|
|
|
// HeadersFromContext retrieves headers set from [SetHeaders]. These headers
|
|
// can then be cast to http.Header or metadata.MD to send along on requests.
|
|
func HeadersFromContext(ctx context.Context) map[string][]string {
|
|
m, ok := ctx.Value(headerKey).(map[string][]string)
|
|
if !ok {
|
|
return nil
|
|
}
|
|
return m
|
|
}
|
|
|
|
// SetHeaders stores key value pairs in the returned context that can later
|
|
// be retrieved by [HeadersFromContext]. Values stored in this manner will
|
|
// automatically be retrieved by client libraries and sent as outgoing headers
|
|
// on all requests. keyvals should have a corresponding value for every key
|
|
// provided. If there is an odd number of keyvals this method will panic.
|
|
func SetHeaders(ctx context.Context, keyvals ...string) context.Context {
|
|
if len(keyvals)%2 != 0 {
|
|
panic(fmt.Sprintf("callctx: an even number of key value pairs must be provided, got %d", len(keyvals)))
|
|
}
|
|
h, ok := ctx.Value(headerKey).(map[string][]string)
|
|
if !ok {
|
|
h = make(map[string][]string)
|
|
} else {
|
|
h = cloneHeaders(h)
|
|
}
|
|
|
|
for i := 0; i < len(keyvals); i = i + 2 {
|
|
h[keyvals[i]] = append(h[keyvals[i]], keyvals[i+1])
|
|
}
|
|
return context.WithValue(ctx, headerKey, h)
|
|
}
|
|
|
|
// cloneHeaders makes a new key-value map while reusing the value slices.
|
|
// As such, new values should be appended to the value slice, and modifying
|
|
// indexed values is not thread safe.
|
|
//
|
|
// TODO: Replace this with maps.Clone when Go 1.21 is the minimum version.
|
|
func cloneHeaders(h map[string][]string) map[string][]string {
|
|
c := make(map[string][]string, len(h))
|
|
for k, v := range h {
|
|
vc := make([]string, len(v))
|
|
copy(vc, v)
|
|
c[k] = vc
|
|
}
|
|
return c
|
|
}
|