/
api.go
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/
api.go
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 variable
import (
"context"
"errors"
"strings"
"mosn.io/mosn/pkg/types"
)
func GetVariableValue(ctx context.Context, name string) (string, error) {
// 1. find built-in variables
if variable, ok := variables[name]; ok {
// 1.1 check indexed value
if indexer, ok := variable.(Indexer); ok {
return getFlushedVariableValue(ctx, indexer.GetIndex())
}
// 1.2 use variable.Getter() to get value
getter := variable.Getter()
if getter == nil {
return "", errors.New(errGetterNotFound + name)
}
return getter(ctx, nil, variable.Data())
}
// 2. find prefix variables
for prefix, variable := range prefixVariables {
if strings.HasPrefix(name, prefix) {
getter := variable.Getter()
if getter == nil {
return "", errors.New(errGetterNotFound + name)
}
return getter(ctx, nil, name)
}
}
return "", errors.New(errUndefinedVariable + name)
}
// TODO: provide direct access to this function, so the cost of variable name finding could be optimized
func getFlushedVariableValue(ctx context.Context, index uint32) (string, error) {
if variables := ctx.Value(types.ContextKeyVariables); variables != nil {
if values, ok := variables.([]IndexedValue); ok {
value := &values[index]
if value.Valid || value.NotFound {
if !value.noCacheable {
return value.data, nil
}
// clear flags
//value.Valid = false
//value.NotFound = false
}
return getIndexedVariableValue(ctx, value, index)
}
}
return "", errors.New(errNoVariablesInContext)
}
func getIndexedVariableValue(ctx context.Context, value *IndexedValue, index uint32) (string, error) {
variable := indexedVariables[index]
//if value.NotFound || value.Valid {
// return value.data, nil
//}
getter := variable.Getter()
if getter == nil {
return "", errors.New(errGetterNotFound + variable.Name())
}
vdata, err := getter(ctx, value, variable.Data())
if err != nil {
value.Valid = false
value.NotFound = true
return vdata, err
}
value.data = vdata
if (variable.Flags() & MOSN_VAR_FLAG_NOCACHEABLE) == 1 {
value.noCacheable = true
}
return value.data, nil
}