discovery service

api/pkg/discovery/kv.go

@@ -0,0 +1,103 @@
+package discovery
+
+import (
+	"encoding/json"
+	"errors"
+	"strings"
+
+	"github.com/nats-io/nats.go"
+	"github.com/tech/sendico/pkg/mlogger"
+	"go.uber.org/zap"
+)
+
+const DefaultKVBucket = "discovery_registry"
+
+type KVStore struct {
+	logger mlogger.Logger
+	kv     nats.KeyValue
+	bucket string
+}
+
+func NewKVStore(logger mlogger.Logger, js nats.JetStreamContext, bucket string) (*KVStore, error) {
+	if js == nil {
+		return nil, errors.New("discovery kv: jetstream is nil")
+	}
+	if logger != nil {
+		logger = logger.Named("discovery_kv")
+	}
+	bucket = strings.TrimSpace(bucket)
+	if bucket == "" {
+		bucket = DefaultKVBucket
+	}
+	kv, err := js.KeyValue(bucket)
+	if err != nil {
+		if errors.Is(err, nats.ErrBucketNotFound) {
+			kv, err = js.CreateKeyValue(&nats.KeyValueConfig{
+				Bucket:      bucket,
+				Description: "service discovery registry",
+				History:     1,
+			})
+			if err == nil && logger != nil {
+				logger.Info("Discovery KV bucket created", zap.String("bucket", bucket))
+			}
+		}
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return &KVStore{
+		logger: logger,
+		kv:     kv,
+		bucket: bucket,
+	}, nil
+}
+
+func (s *KVStore) Put(entry RegistryEntry) error {
+	if s == nil || s.kv == nil {
+		return errors.New("discovery kv: not configured")
+	}
+	key := registryEntryKey(normalizeEntry(entry))
+	if key == "" {
+		return errors.New("discovery kv: entry key is empty")
+	}
+	payload, err := json.Marshal(entry)
+	if err != nil {
+		return err
+	}
+	_, err = s.kv.Put(kvKeyFromRegistryKey(key), payload)
+	if err != nil && s.logger != nil {
+		fields := append(entryFields(entry), zap.String("bucket", s.bucket), zap.String("key", key), zap.Error(err))
+		s.logger.Warn("Failed to persist discovery entry", fields...)
+	}
+	return err
+}
+
+func (s *KVStore) Delete(id string) error {
+	if s == nil || s.kv == nil {
+		return errors.New("discovery kv: not configured")
+	}
+	key := kvKeyFromRegistryKey(id)
+	if key == "" {
+		return nil
+	}
+	if err := s.kv.Delete(key); err != nil && s.logger != nil {
+		s.logger.Warn("Failed to delete discovery entry", zap.String("bucket", s.bucket), zap.String("key", key), zap.Error(err))
+		return err
+	}
+	return nil
+}
+
+func (s *KVStore) WatchAll() (nats.KeyWatcher, error) {
+	if s == nil || s.kv == nil {
+		return nil, errors.New("discovery kv: not configured")
+	}
+	return s.kv.WatchAll()
+}
+
+func (s *KVStore) Bucket() string {
+	if s == nil {
+		return ""
+	}
+	return s.bucket
+}