forked from TrueCloudLab/distribution
101 lines
3.2 KiB
Go
101 lines
3.2 KiB
Go
// Copyright 2015 Google Inc. All rights reserved.
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// Use of this source code is governed by the Apache 2.0
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// license that can be found in the LICENSE file.
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package internal
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import (
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"github.com/golang/protobuf/proto"
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netcontext "golang.org/x/net/context"
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)
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type CallOverrideFunc func(ctx netcontext.Context, service, method string, in, out proto.Message) error
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var callOverrideKey = "holds []CallOverrideFunc"
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func WithCallOverride(ctx netcontext.Context, f CallOverrideFunc) netcontext.Context {
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// We avoid appending to any existing call override
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// so we don't risk overwriting a popped stack below.
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var cofs []CallOverrideFunc
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if uf, ok := ctx.Value(&callOverrideKey).([]CallOverrideFunc); ok {
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cofs = append(cofs, uf...)
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}
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cofs = append(cofs, f)
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return netcontext.WithValue(ctx, &callOverrideKey, cofs)
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}
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func callOverrideFromContext(ctx netcontext.Context) (CallOverrideFunc, netcontext.Context, bool) {
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cofs, _ := ctx.Value(&callOverrideKey).([]CallOverrideFunc)
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if len(cofs) == 0 {
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return nil, nil, false
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}
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// We found a list of overrides; grab the last, and reconstitute a
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// context that will hide it.
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f := cofs[len(cofs)-1]
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ctx = netcontext.WithValue(ctx, &callOverrideKey, cofs[:len(cofs)-1])
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return f, ctx, true
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}
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type logOverrideFunc func(level int64, format string, args ...interface{})
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var logOverrideKey = "holds a logOverrideFunc"
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func WithLogOverride(ctx netcontext.Context, f logOverrideFunc) netcontext.Context {
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return netcontext.WithValue(ctx, &logOverrideKey, f)
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}
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var appIDOverrideKey = "holds a string, being the full app ID"
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func WithAppIDOverride(ctx netcontext.Context, appID string) netcontext.Context {
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return netcontext.WithValue(ctx, &appIDOverrideKey, appID)
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}
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var namespaceKey = "holds the namespace string"
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func withNamespace(ctx netcontext.Context, ns string) netcontext.Context {
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return netcontext.WithValue(ctx, &namespaceKey, ns)
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}
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func NamespaceFromContext(ctx netcontext.Context) string {
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// If there's no namespace, return the empty string.
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ns, _ := ctx.Value(&namespaceKey).(string)
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return ns
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}
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// FullyQualifiedAppID returns the fully-qualified application ID.
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// This may contain a partition prefix (e.g. "s~" for High Replication apps),
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// or a domain prefix (e.g. "example.com:").
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func FullyQualifiedAppID(ctx netcontext.Context) string {
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if id, ok := ctx.Value(&appIDOverrideKey).(string); ok {
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return id
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}
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return fullyQualifiedAppID(ctx)
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}
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func Logf(ctx netcontext.Context, level int64, format string, args ...interface{}) {
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if f, ok := ctx.Value(&logOverrideKey).(logOverrideFunc); ok {
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f(level, format, args...)
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return
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}
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logf(fromContext(ctx), level, format, args...)
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}
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// NamespacedContext wraps a Context to support namespaces.
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func NamespacedContext(ctx netcontext.Context, namespace string) netcontext.Context {
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n := &namespacedContext{
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namespace: namespace,
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}
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return withNamespace(WithCallOverride(ctx, n.call), namespace)
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}
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type namespacedContext struct {
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namespace string
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}
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func (n *namespacedContext) call(ctx netcontext.Context, service, method string, in, out proto.Message) error {
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// Apply any namespace mods.
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if mod, ok := NamespaceMods[service]; ok {
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mod(in, n.namespace)
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}
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return Call(ctx, service, method, in, out)
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}
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