package memory import ( "bytes" "container/list" "errors" "fmt" "strings" "sync" "time" "github.com/micro/go-micro/v2/config/loader" "github.com/micro/go-micro/v2/config/reader" "github.com/micro/go-micro/v2/config/reader/json" "github.com/micro/go-micro/v2/config/source" ) type memory struct { exit chan bool opts loader.Options sync.RWMutex // the current snapshot snap *loader.Snapshot // the current values vals reader.Values // all the sets sets []*source.ChangeSet // all the sources sources []source.Source watchers *list.List } type updateValue struct { version string value reader.Value } type watcher struct { exit chan bool path []string value reader.Value reader reader.Reader version string updates chan updateValue } func (m *memory) watch(idx int, s source.Source) { // watches a source for changes watch := func(idx int, s source.Watcher) error { for { // get changeset cs, err := s.Next() if err != nil { return err } m.Lock() // save m.sets[idx] = cs // merge sets set, err := m.opts.Reader.Merge(m.sets...) if err != nil { m.Unlock() return err } // set values m.vals, _ = m.opts.Reader.Values(set) m.snap = &loader.Snapshot{ ChangeSet: set, Version: genVer(), } m.Unlock() // send watch updates m.update() } } for { // watch the source w, err := s.Watch() if err != nil { time.Sleep(time.Second) continue } done := make(chan bool) // the stop watch func go func() { select { case <-done: case <-m.exit: } w.Stop() }() // block watch if err := watch(idx, w); err != nil { // do something better time.Sleep(time.Second) } // close done chan close(done) // if the config is closed exit select { case <-m.exit: return default: } } } func (m *memory) loaded() bool { var loaded bool m.RLock() if m.vals != nil { loaded = true } m.RUnlock() return loaded } // reload reads the sets and creates new values func (m *memory) reload() error { m.Lock() // merge sets set, err := m.opts.Reader.Merge(m.sets...) if err != nil { m.Unlock() return err } // set values m.vals, _ = m.opts.Reader.Values(set) m.snap = &loader.Snapshot{ ChangeSet: set, Version: genVer(), } m.Unlock() // update watchers m.update() return nil } func (m *memory) update() { watchers := make([]*watcher, 0, m.watchers.Len()) m.RLock() for e := m.watchers.Front(); e != nil; e = e.Next() { watchers = append(watchers, e.Value.(*watcher)) } vals := m.vals snap := m.snap m.RUnlock() for _, w := range watchers { if w.version >= snap.Version { continue } uv := updateValue{ version: m.snap.Version, value: vals.Get(w.path...), } select { case w.updates <- uv: default: } } } // Snapshot returns a snapshot of the current loaded config func (m *memory) Snapshot() (*loader.Snapshot, error) { if m.loaded() { m.RLock() snap := loader.Copy(m.snap) m.RUnlock() return snap, nil } // not loaded, sync if err := m.Sync(); err != nil { return nil, err } // make copy m.RLock() snap := loader.Copy(m.snap) m.RUnlock() return snap, nil } // Sync loads all the sources, calls the parser and updates the config func (m *memory) Sync() error { //nolint:prealloc var sets []*source.ChangeSet m.Lock() // read the source var gerr []string for _, source := range m.sources { ch, err := source.Read() if err != nil { gerr = append(gerr, err.Error()) continue } sets = append(sets, ch) } // merge sets set, err := m.opts.Reader.Merge(sets...) if err != nil { m.Unlock() return err } // set values vals, err := m.opts.Reader.Values(set) if err != nil { m.Unlock() return err } m.vals = vals m.snap = &loader.Snapshot{ ChangeSet: set, Version: genVer(), } m.Unlock() // update watchers m.update() if len(gerr) > 0 { return fmt.Errorf("source loading errors: %s", strings.Join(gerr, "\n")) } return nil } func (m *memory) Close() error { select { case <-m.exit: return nil default: close(m.exit) } return nil } func (m *memory) Get(path ...string) (reader.Value, error) { if !m.loaded() { if err := m.Sync(); err != nil { return nil, err } } m.Lock() defer m.Unlock() // did sync actually work? if m.vals != nil { return m.vals.Get(path...), nil } // assuming vals is nil // create new vals ch := m.snap.ChangeSet // we are truly screwed, trying to load in a hacked way v, err := m.opts.Reader.Values(ch) if err != nil { return nil, err } // lets set it just because m.vals = v if m.vals != nil { return m.vals.Get(path...), nil } // ok we're going hardcore now return nil, errors.New("no values") } func (m *memory) Load(sources ...source.Source) error { var gerrors []string for _, source := range sources { set, err := source.Read() if err != nil { gerrors = append(gerrors, fmt.Sprintf("error loading source %s: %v", source, err)) // continue processing continue } m.Lock() m.sources = append(m.sources, source) m.sets = append(m.sets, set) idx := len(m.sets) - 1 m.Unlock() go m.watch(idx, source) } if err := m.reload(); err != nil { gerrors = append(gerrors, err.Error()) } // Return errors if len(gerrors) != 0 { return errors.New(strings.Join(gerrors, "\n")) } return nil } func (m *memory) Watch(path ...string) (loader.Watcher, error) { value, err := m.Get(path...) if err != nil { return nil, err } m.Lock() w := &watcher{ exit: make(chan bool), path: path, value: value, reader: m.opts.Reader, updates: make(chan updateValue, 1), version: m.snap.Version, } e := m.watchers.PushBack(w) m.Unlock() go func() { <-w.exit m.Lock() m.watchers.Remove(e) m.Unlock() }() return w, nil } func (m *memory) String() string { return "memory" } func (w *watcher) Next() (*loader.Snapshot, error) { update := func(v reader.Value) *loader.Snapshot { w.value = v cs := &source.ChangeSet{ Data: v.Bytes(), Format: w.reader.String(), Source: "memory", Timestamp: time.Now(), } cs.Checksum = cs.Sum() return &loader.Snapshot{ ChangeSet: cs, Version: w.version, } } for { select { case <-w.exit: return nil, errors.New("watcher stopped") case uv := <-w.updates: if uv.version <= w.version { continue } v := uv.value w.version = uv.version if bytes.Equal(w.value.Bytes(), v.Bytes()) { continue } return update(v), nil } } } func (w *watcher) Stop() error { select { case <-w.exit: default: close(w.exit) close(w.updates) } return nil } func genVer() string { return fmt.Sprintf("%d", time.Now().UnixNano()) } func NewLoader(opts ...loader.Option) loader.Loader { options := loader.Options{ Reader: json.NewReader(), } for _, o := range opts { o(&options) } m := &memory{ exit: make(chan bool), opts: options, watchers: list.New(), sources: options.Source, } m.sets = make([]*source.ChangeSet, len(options.Source)) for i, s := range options.Source { m.sets[i] = &source.ChangeSet{Source: s.String()} go m.watch(i, s) } return m }