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package client
import (
"context"
"io/ioutil"
"os"
"sync"
"github.com/google/renameio"
"gopkg.in/yaml.v2"
"github.com/canonical/go-dqlite/v2/internal/protocol"
)
// NodeStore is used by a dqlite client to get an initial list of candidate
// dqlite nodes that it can dial in order to find a leader dqlite node to use.
type NodeStore = protocol.NodeStore
// NodeRole identifies the role of a node.
type NodeRole = protocol.NodeRole
// NodeInfo holds information about a single server.
type NodeInfo = protocol.NodeInfo
// InmemNodeStore keeps the list of target dqlite nodes in memory.
type InmemNodeStore = protocol.InmemNodeStore
// NewInmemNodeStore creates NodeStore which stores its data in-memory.
var NewInmemNodeStore = protocol.NewInmemNodeStore
// Persists a list addresses of dqlite nodes in a YAML file.
type YamlNodeStore struct {
path string
servers []NodeInfo
mu sync.RWMutex
}
// NewYamlNodeStore creates a new YamlNodeStore backed by the given YAML file.
func NewYamlNodeStore(path string) (*YamlNodeStore, error) {
servers := []NodeInfo{}
_, err := os.Stat(path)
if err != nil {
if !os.IsNotExist(err) {
return nil, err
}
} else {
data, err := ioutil.ReadFile(path)
if err != nil {
return nil, err
}
if err := yaml.Unmarshal(data, &servers); err != nil {
return nil, err
}
}
store := &YamlNodeStore{
path: path,
servers: servers,
}
return store, nil
}
// Get the current servers.
func (s *YamlNodeStore) Get(ctx context.Context) ([]NodeInfo, error) {
s.mu.RLock()
defer s.mu.RUnlock()
ret := make([]NodeInfo, len(s.servers))
copy(ret, s.servers)
return ret, nil
}
// Set the servers addresses.
func (s *YamlNodeStore) Set(ctx context.Context, servers []NodeInfo) error {
s.mu.Lock()
defer s.mu.Unlock()
data, err := yaml.Marshal(servers)
if err != nil {
return err
}
if err := renameio.WriteFile(s.path, data, 0600); err != nil {
return err
}
s.servers = servers
return nil
}
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