go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/server/settings/memory.go (about)

     1  // Copyright 2015 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package settings
    16  
    17  import (
    18  	"context"
    19  	"encoding/json"
    20  	"sync"
    21  	"time"
    22  )
    23  
    24  // MemoryStorage implements Storage interface, using memory as a backend. Useful
    25  // in unit tests.
    26  type MemoryStorage struct {
    27  	Expiration time.Duration // default expiration time of in-memory cache
    28  
    29  	lock   sync.Mutex
    30  	values map[string]*json.RawMessage
    31  }
    32  
    33  // FetchAllSettings fetches all latest settings at once.
    34  func (m *MemoryStorage) FetchAllSettings(c context.Context) (*Bundle, time.Duration, error) {
    35  	m.lock.Lock()
    36  	defer m.lock.Unlock()
    37  	values := make(map[string]*json.RawMessage, len(m.values))
    38  	for k, v := range m.values {
    39  		if v == nil {
    40  			values[k] = v
    41  		} else {
    42  			raw := append(json.RawMessage(nil), *v...)
    43  			values[k] = &raw
    44  		}
    45  	}
    46  	return &Bundle{Values: values}, m.Expiration, nil
    47  }
    48  
    49  // UpdateSetting updates a setting at the given key.
    50  func (m *MemoryStorage) UpdateSetting(c context.Context, key string, value json.RawMessage) error {
    51  	m.lock.Lock()
    52  	defer m.lock.Unlock()
    53  	if m.values == nil {
    54  		m.values = make(map[string]*json.RawMessage, 1)
    55  	}
    56  	cpy := append(json.RawMessage(nil), value...)
    57  	m.values[key] = &cpy
    58  	return nil
    59  }