package datastore import ( "fmt" "log" "reflect" "strings" "sync" "github.com/docker/libkv" "github.com/docker/libkv/store" "github.com/docker/libnetwork/discoverapi" "github.com/docker/libnetwork/types" ) //DataStore exported type DataStore interface { // GetObject gets data from datastore and unmarshals to the specified object GetObject(key string, o KVObject) error // PutObject adds a new Record based on an object into the datastore PutObject(kvObject KVObject) error // PutObjectAtomic provides an atomic add and update operation for a Record PutObjectAtomic(kvObject KVObject) error // DeleteObject deletes a record DeleteObject(kvObject KVObject) error // DeleteObjectAtomic performs an atomic delete operation DeleteObjectAtomic(kvObject KVObject) error // DeleteTree deletes a record DeleteTree(kvObject KVObject) error // Watchable returns whether the store is watchable or not Watchable() bool // Watch for changes on a KVObject Watch(kvObject KVObject, stopCh <-chan struct{}) (<-chan KVObject, error) // RestartWatch retriggers stopped Watches RestartWatch() // Active returns if the store is active Active() bool // List returns of a list of KVObjects belonging to the parent // key. The caller must pass a KVObject of the same type as // the objects that need to be listed List(string, KVObject) ([]KVObject, error) // Scope returns the scope of the store Scope() string // KVStore returns access to the KV Store KVStore() store.Store // Close closes the data store Close() } // ErrKeyModified is raised for an atomic update when the update is working on a stale state var ( ErrKeyModified = store.ErrKeyModified ErrKeyNotFound = store.ErrKeyNotFound ) type datastore struct { scope string store store.Store cache *cache watchCh chan struct{} active bool sync.Mutex } // KVObject is Key/Value interface used by objects to be part of the DataStore type KVObject interface { // Key method lets an object to provide the Key to be used in KV Store Key() []string // KeyPrefix method lets an object to return immediate parent key that can be used for tree walk KeyPrefix() []string // Value method lets an object to marshal its content to be stored in the KV store Value() []byte // SetValue is used by the datastore to set the object's value when loaded from the data store. SetValue([]byte) error // Index method returns the latest DB Index as seen by the object Index() uint64 // SetIndex method allows the datastore to store the latest DB Index into the object SetIndex(uint64) // True if the object exists in the datastore, false if it hasn't been stored yet. // When SetIndex() is called, the object has been stored. Exists() bool // DataScope indicates the storage scope of the KV object DataScope() string // Skip provides a way for a KV Object to avoid persisting it in the KV Store Skip() bool } // KVConstructor interface defines methods which can construct a KVObject from another. type KVConstructor interface { // New returns a new object which is created based on the // source object New() KVObject // CopyTo deep copies the contents of the implementing object // to the passed destination object CopyTo(KVObject) error } // ScopeCfg represents Datastore configuration. type ScopeCfg struct { Client ScopeClientCfg } // ScopeClientCfg represents Datastore Client-only mode configuration type ScopeClientCfg struct { Provider string Address string Config *store.Config } const ( // LocalScope indicates to store the KV object in local datastore such as boltdb LocalScope = "local" // GlobalScope indicates to store the KV object in global datastore such as consul/etcd/zookeeper GlobalScope = "global" defaultPrefix = "/var/lib/docker/network/files" ) const ( // NetworkKeyPrefix is the prefix for network key in the kv store NetworkKeyPrefix = "network" // EndpointKeyPrefix is the prefix for endpoint key in the kv store EndpointKeyPrefix = "endpoint" ) var ( defaultScopes = makeDefaultScopes() ) func makeDefaultScopes() map[string]*ScopeCfg { def := make(map[string]*ScopeCfg) def[LocalScope] = &ScopeCfg{ Client: ScopeClientCfg{ Provider: string(store.BOLTDB), Address: defaultPrefix + "/local-kv.db", Config: &store.Config{ Bucket: "libnetwork", }, }, } return def } var defaultRootChain = []string{"docker", "network", "v1.0"} var rootChain = defaultRootChain // DefaultScopes returns a map of default scopes and it's config for clients to use. func DefaultScopes(dataDir string) map[string]*ScopeCfg { if dataDir != "" { defaultScopes[LocalScope].Client.Address = dataDir + "/network/files/local-kv.db" return defaultScopes } defaultScopes[LocalScope].Client.Address = defaultPrefix + "/local-kv.db" return defaultScopes } // IsValid checks if the scope config has valid configuration. func (cfg *ScopeCfg) IsValid() bool { if cfg == nil || strings.TrimSpace(cfg.Client.Provider) == "" || strings.TrimSpace(cfg.Client.Address) == "" { return false } return true } //Key provides convenient method to create a Key func Key(key ...string) string { keychain := append(rootChain, key...) str := strings.Join(keychain, "/") return str + "/" } //ParseKey provides convenient method to unpack the key to complement the Key function func ParseKey(key string) ([]string, error) { chain := strings.Split(strings.Trim(key, "/"), "/") // The key must atleast be equal to the rootChain in order to be considered as valid if len(chain) <= len(rootChain) || !reflect.DeepEqual(chain[0:len(rootChain)], rootChain) { return nil, types.BadRequestErrorf("invalid Key : %s", key) } return chain[len(rootChain):], nil } // newClient used to connect to KV Store func newClient(scope string, kv string, addr string, config *store.Config, cached bool) (DataStore, error) { if cached && scope != LocalScope { return nil, fmt.Errorf("caching supported only for scope %s", LocalScope) } if config == nil { config = &store.Config{} } var addrs []string if kv == string(store.BOLTDB) { // Parse file path addrs = strings.Split(addr, ",") } else { // Parse URI parts := strings.SplitN(addr, "/", 2) addrs = strings.Split(parts[0], ",") // Add the custom prefix to the root chain if len(parts) == 2 { rootChain = append([]string{parts[1]}, defaultRootChain...) } } store, err := libkv.NewStore(store.Backend(kv), addrs, config) if err != nil { return nil, err } ds := &datastore{scope: scope, store: store, active: true, watchCh: make(chan struct{})} if cached { ds.cache = newCache(ds) } return ds, nil } // NewDataStore creates a new instance of LibKV data store func NewDataStore(scope string, cfg *ScopeCfg) (DataStore, error) { if cfg == nil || cfg.Client.Provider == "" || cfg.Client.Address == "" { c, ok := defaultScopes[scope] if !ok || c.Client.Provider == "" || c.Client.Address == "" { return nil, fmt.Errorf("unexpected scope %s without configuration passed", scope) } cfg = c } var cached bool if scope == LocalScope { cached = true } return newClient(scope, cfg.Client.Provider, cfg.Client.Address, cfg.Client.Config, cached) } // NewDataStoreFromConfig creates a new instance of LibKV data store starting from the datastore config data func NewDataStoreFromConfig(dsc discoverapi.DatastoreConfigData) (DataStore, error) { var ( ok bool sCfgP *store.Config ) sCfgP, ok = dsc.Config.(*store.Config) if !ok && dsc.Config != nil { return nil, fmt.Errorf("cannot parse store configuration: %v", dsc.Config) } scopeCfg := &ScopeCfg{ Client: ScopeClientCfg{ Address: dsc.Address, Provider: dsc.Provider, Config: sCfgP, }, } ds, err := NewDataStore(dsc.Scope, scopeCfg) if err != nil { return nil, fmt.Errorf("failed to construct datastore client from datastore configuration %v: %v", dsc, err) } return ds, err } func (ds *datastore) Close() { ds.store.Close() } func (ds *datastore) Scope() string { return ds.scope } func (ds *datastore) Active() bool { return ds.active } func (ds *datastore) Watchable() bool { return ds.scope != LocalScope } func (ds *datastore) Watch(kvObject KVObject, stopCh <-chan struct{}) (<-chan KVObject, error) { sCh := make(chan struct{}) ctor, ok := kvObject.(KVConstructor) if !ok { return nil, fmt.Errorf("error watching object type %T, object does not implement KVConstructor interface", kvObject) } kvpCh, err := ds.store.Watch(Key(kvObject.Key()...), sCh) if err != nil { return nil, err } kvoCh := make(chan KVObject) go func() { retry_watch: var err error // Make sure to get a new instance of watch channel ds.Lock() watchCh := ds.watchCh ds.Unlock() loop: for { select { case <-stopCh: close(sCh) return case kvPair := <-kvpCh: // If the backend KV store gets reset libkv's go routine // for the watch can exit resulting in a nil value in // channel. if kvPair == nil { ds.Lock() ds.active = false ds.Unlock() break loop } dstO := ctor.New() if err = dstO.SetValue(kvPair.Value); err != nil { log.Printf("Could not unmarshal kvpair value = %s", string(kvPair.Value)) break } dstO.SetIndex(kvPair.LastIndex) kvoCh <- dstO } } // Wait on watch channel for a re-trigger when datastore becomes active <-watchCh kvpCh, err = ds.store.Watch(Key(kvObject.Key()...), sCh) if err != nil { log.Printf("Could not watch the key %s in store: %v", Key(kvObject.Key()...), err) } goto retry_watch }() return kvoCh, nil } func (ds *datastore) RestartWatch() { ds.Lock() defer ds.Unlock() ds.active = true watchCh := ds.watchCh ds.watchCh = make(chan struct{}) close(watchCh) } func (ds *datastore) KVStore() store.Store { return ds.store } // PutObjectAtomic adds a new Record based on an object into the datastore func (ds *datastore) PutObjectAtomic(kvObject KVObject) error { var ( previous *store.KVPair pair *store.KVPair err error ) ds.Lock() defer ds.Unlock() if kvObject == nil { return types.BadRequestErrorf("invalid KV Object : nil") } kvObjValue := kvObject.Value() if kvObjValue == nil { return types.BadRequestErrorf("invalid KV Object with a nil Value for key %s", Key(kvObject.Key()...)) } if kvObject.Skip() { goto add_cache } if kvObject.Exists() { previous = &store.KVPair{Key: Key(kvObject.Key()...), LastIndex: kvObject.Index()} } else { previous = nil } _, pair, err = ds.store.AtomicPut(Key(kvObject.Key()...), kvObjValue, previous, nil) if err != nil { if err == store.ErrKeyExists { return ErrKeyModified } return err } kvObject.SetIndex(pair.LastIndex) add_cache: if ds.cache != nil { return ds.cache.add(kvObject) } return nil } // PutObject adds a new Record based on an object into the datastore func (ds *datastore) PutObject(kvObject KVObject) error { ds.Lock() defer ds.Unlock() if kvObject == nil { return types.BadRequestErrorf("invalid KV Object : nil") } if kvObject.Skip() { goto add_cache } if err := ds.putObjectWithKey(kvObject, kvObject.Key()...); err != nil { return err } add_cache: if ds.cache != nil { return ds.cache.add(kvObject) } return nil } func (ds *datastore) putObjectWithKey(kvObject KVObject, key ...string) error { kvObjValue := kvObject.Value() if kvObjValue == nil { return types.BadRequestErrorf("invalid KV Object with a nil Value for key %s", Key(kvObject.Key()...)) } return ds.store.Put(Key(key...), kvObjValue, nil) } // GetObject returns a record matching the key func (ds *datastore) GetObject(key string, o KVObject) error { ds.Lock() defer ds.Unlock() if ds.cache != nil { return ds.cache.get(key, o) } kvPair, err := ds.store.Get(key) if err != nil { return err } if err := o.SetValue(kvPair.Value); err != nil { return err } // Make sure the object has a correct view of the DB index in // case we need to modify it and update the DB. o.SetIndex(kvPair.LastIndex) return nil } func (ds *datastore) ensureParent(parent string) error { exists, err := ds.store.Exists(parent) if err != nil { return err } if exists { return nil } return ds.store.Put(parent, []byte{}, &store.WriteOptions{IsDir: true}) } func (ds *datastore) List(key string, kvObject KVObject) ([]KVObject, error) { ds.Lock() defer ds.Unlock() if ds.cache != nil { return ds.cache.list(kvObject) } // Bail out right away if the kvObject does not implement KVConstructor ctor, ok := kvObject.(KVConstructor) if !ok { return nil, fmt.Errorf("error listing objects, object does not implement KVConstructor interface") } // Make sure the parent key exists if err := ds.ensureParent(key); err != nil { return nil, err } kvList, err := ds.store.List(key) if err != nil { return nil, err } var kvol []KVObject for _, kvPair := range kvList { if len(kvPair.Value) == 0 { continue } dstO := ctor.New() if err := dstO.SetValue(kvPair.Value); err != nil { return nil, err } // Make sure the object has a correct view of the DB index in // case we need to modify it and update the DB. dstO.SetIndex(kvPair.LastIndex) kvol = append(kvol, dstO) } return kvol, nil } // DeleteObject unconditionally deletes a record from the store func (ds *datastore) DeleteObject(kvObject KVObject) error { ds.Lock() defer ds.Unlock() // cleaup the cache first if ds.cache != nil { ds.cache.del(kvObject) } if kvObject.Skip() { return nil } return ds.store.Delete(Key(kvObject.Key()...)) } // DeleteObjectAtomic performs atomic delete on a record func (ds *datastore) DeleteObjectAtomic(kvObject KVObject) error { ds.Lock() defer ds.Unlock() if kvObject == nil { return types.BadRequestErrorf("invalid KV Object : nil") } previous := &store.KVPair{Key: Key(kvObject.Key()...), LastIndex: kvObject.Index()} if kvObject.Skip() { goto del_cache } if _, err := ds.store.AtomicDelete(Key(kvObject.Key()...), previous); err != nil { if err == store.ErrKeyExists { return ErrKeyModified } return err } del_cache: // cleanup the cache only if AtomicDelete went through successfully if ds.cache != nil { return ds.cache.del(kvObject) } return nil } // DeleteTree unconditionally deletes a record from the store func (ds *datastore) DeleteTree(kvObject KVObject) error { ds.Lock() defer ds.Unlock() // cleaup the cache first if ds.cache != nil { ds.cache.del(kvObject) } if kvObject.Skip() { return nil } return ds.store.DeleteTree(Key(kvObject.KeyPrefix()...)) }