/
context.go
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/
context.go
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// Copyright (c) 2021 - The Event Horizon authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package namespace
import (
"context"
eh "github.com/looplab/eventhorizon"
)
// DefaultNamespace is the namespace to use if not set in the context.
const DefaultNamespace = "default"
// Strings used to marshal context values.
const (
namespaceKeyStr = "eh_namespace"
)
func init() {
eh.RegisterContextMarshaler(func(ctx context.Context, vals map[string]interface{}) {
if ns, ok := ctx.Value(namespaceKey).(string); ok {
vals[namespaceKeyStr] = ns
}
})
eh.RegisterContextUnmarshaler(func(ctx context.Context, vals map[string]interface{}) context.Context {
if ns, ok := vals[namespaceKeyStr].(string); ok {
ctx = NewContext(ctx, ns)
}
return ctx
})
}
type contextKey int
const (
namespaceKey contextKey = iota
)
// FromContext returns the namespace from the context, or the default namespace.
func FromContext(ctx context.Context) string {
if ns, ok := ctx.Value(namespaceKey).(string); ok {
return ns
}
return DefaultNamespace
}
// NewContext sets the namespace to use in the context. The namespace is used to
// determine which database to use, among other things.
func NewContext(ctx context.Context, namespace string) context.Context {
return context.WithValue(ctx, namespaceKey, namespace)
}