Initial QSfera import

Server/vendor/go-micro.dev/v4/events/store.go

@@ -0,0 +1,129 @@
+package events
+
+import (
+	"encoding/json"
+	"time"
+
+	"github.com/pkg/errors"
+	log "go-micro.dev/v4/logger"
+	"go-micro.dev/v4/store"
+)
+
+const joinKey = "/"
+
+// NewStore returns an initialized events store.
+func NewStore(opts ...StoreOption) Store {
+	// parse the options
+	var options StoreOptions
+	for _, o := range opts {
+		o(&options)
+	}
+	if options.TTL.Seconds() == 0 {
+		options.TTL = time.Hour * 24
+	}
+
+	options.Logger = log.LoggerOrDefault(options.Logger)
+
+	// return the store
+	evs := &evStore{
+		opts:  options,
+		store: store.NewMemoryStore(),
+	}
+	if options.Backup != nil {
+		go evs.backupLoop()
+	}
+	return evs
+}
+
+type evStore struct {
+	opts  StoreOptions
+	store store.Store
+}
+
+// Read events for a topic.
+func (s *evStore) Read(topic string, opts ...ReadOption) ([]*Event, error) {
+	// validate the topic
+	if len(topic) == 0 {
+		return nil, ErrMissingTopic
+	}
+
+	// parse the options
+	options := ReadOptions{
+		Offset: 0,
+		Limit:  250,
+	}
+	for _, o := range opts {
+		o(&options)
+	}
+
+	// execute the request
+	recs, err := s.store.Read(topic+joinKey,
+		store.ReadPrefix(),
+		store.ReadLimit(options.Limit),
+		store.ReadOffset(options.Offset),
+	)
+	if err != nil {
+		return nil, errors.Wrap(err, "Error reading from store")
+	}
+
+	// unmarshal the result
+	result := make([]*Event, len(recs))
+	for i, r := range recs {
+		var e Event
+		if err := json.Unmarshal(r.Value, &e); err != nil {
+			return nil, errors.Wrap(err, "Invalid event returned from stroe")
+		}
+		result[i] = &e
+	}
+
+	return result, nil
+}
+
+// Write an event to the store.
+func (s *evStore) Write(event *Event, opts ...WriteOption) error {
+	// parse the options
+	options := WriteOptions{
+		TTL: s.opts.TTL,
+	}
+	for _, o := range opts {
+		o(&options)
+	}
+
+	// construct the store record
+	bytes, err := json.Marshal(event)
+	if err != nil {
+		return errors.Wrap(err, "Error mashaling event to JSON")
+	}
+	// suffix event ID with hour resolution for easy retrieval in batches
+	timeSuffix := time.Now().Format("2006010215")
+
+	record := &store.Record{
+		// key is such that reading by prefix indexes by topic and reading by suffix indexes by time
+		Key:    event.Topic + joinKey + event.ID + joinKey + timeSuffix,
+		Value:  bytes,
+		Expiry: options.TTL,
+	}
+
+	// write the record to the store
+	if err := s.store.Write(record); err != nil {
+		return errors.Wrap(err, "Error writing to the store")
+	}
+
+	return nil
+}
+
+func (s *evStore) backupLoop() {
+	for {
+		err := s.opts.Backup.Snapshot(s.store)
+		if err != nil {
+			s.opts.Logger.Logf(log.ErrorLevel, "Error running backup %s", err)
+		}
+
+		time.Sleep(1 * time.Hour)
+	}
+}
+
+// Backup is an interface for snapshotting the events store to long term storage.
+type Backup interface {
+	Snapshot(st store.Store) error
+}