store: refactor interface

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

store/noop.go

@@ -29,12 +29,17 @@ func (n *noopStore) String() string {
 }
 
 // Read reads store value by key
-func (n *noopStore) Read(ctx context.Context, key string, opts ...ReadOption) ([]*Record, error) {
-	return []*Record{}, nil
+func (n *noopStore) Exists(ctx context.Context, key string) error {
+	return ErrNotFound
+}
+
+// Read reads store value by key
+func (n *noopStore) Read(ctx context.Context, key string, val interface{}, opts ...ReadOption) error {
+	return ErrNotFound
 }
 
 // Write writes store record
-func (n *noopStore) Write(ctx context.Context, r *Record, opts ...WriteOption) error {
+func (n *noopStore) Write(ctx context.Context, key string, val interface{}, opts ...WriteOption) error {
 	return nil
 }
 

store/options.go

@@ -4,7 +4,9 @@ import (
 	"context"
 	"time"
 
+	"github.com/unistack-org/micro/v3/codec"
 	"github.com/unistack-org/micro/v3/logger"
+	"github.com/unistack-org/micro/v3/metadata"
 )
 
 // Options contains configuration for the Store
@@ -17,6 +19,8 @@ type Options struct {
 	Database string
 	// Table is analag for a table in database backends or a key prefix in KV backends
 	Table string
+	// Codec that used for marshal/unmarshal value
+	Codec codec.Codec
 	// Logger the logger
 	Logger logger.Logger
 	// Context should contain all implementation specific options, using context.WithValue.
@@ -45,6 +49,13 @@ func Context(ctx context.Context) Option {
 	}
 }
 
+// Codec sets the codec
+func Codec(c codec.Codec) Option {
+	return func(o *Options) {
+		o.Codec = c
+	}
+}
+
 // Logger sets the logger
 func Logger(l logger.Logger) Option {
 	return func(o *Options) {
@@ -130,11 +141,13 @@ func ReadOffset(o uint) ReadOption {
 // WriteOptions configures an individual Write operation
 // If Expiry and TTL are set TTL takes precedence
 type WriteOptions struct {
-	Database, Table string
+	Database string
+	Table    string
 	// Expiry is the time the record expires
 	Expiry time.Time
 	// TTL is the time until the record expires
-	TTL time.Duration
+	TTL      time.Duration
+	Metadata metadata.Metadata
 }
 
 // WriteOption sets values in WriteOptions
@@ -162,6 +175,13 @@ func WriteTTL(d time.Duration) WriteOption {
 	}
 }
 
+// WriteMetadata add metadata.Metadata
+func WriteMetadata(md metadata.Metadata) WriteOption {
+	return func(w *WriteOptions) {
+		w.Metadata = metadata.Copy(md)
+	}
+}
+
 // DeleteOptions configures an individual Delete operation
 type DeleteOptions struct {
 	Database, Table string

store/store.go

@@ -5,7 +5,8 @@ package store
 import (
 	"context"
 	"errors"
-	"time"
+
+	"github.com/unistack-org/micro/v3/metadata"
 )
 
 var (
@@ -23,10 +24,12 @@ type Store interface {
 	Connect(ctx context.Context) error
 	// Options allows you to view the current options.
 	Options() Options
-	// Read takes a single key name and optional ReadOptions. It returns matching []*Record or an error.
-	Read(ctx context.Context, key string, opts ...ReadOption) ([]*Record, error)
-	// Write() writes a record to the store, and returns an error if the record was not written.
-	Write(ctx context.Context, r *Record, opts ...WriteOption) error
+	// Exists check that key exists in store
+	Exists(ctx context.Context, key string) error
+	// Read reads a single key name to provided value with optional ReadOptions
+	Read(ctx context.Context, key string, val interface{}, opts ...ReadOption) error
+	// Write writes a value to key name to the store with optional WriteOption
+	Write(ctx context.Context, key string, val interface{}, opts ...WriteOption) error
 	// Delete removes the record with the corresponding key from the store.
 	Delete(ctx context.Context, key string, opts ...DeleteOption) error
 	// List returns any keys that match, or an empty list with no error if none matched.
@@ -37,14 +40,11 @@ type Store interface {
 	String() string
 }
 
-// Record is an item stored or retrieved from a Store
-type Record struct {
-	// The key to store the record
-	Key string `json:"key"`
-	// The value within the record
-	Value []byte `json:"value"`
-	// Any associated metadata for indexing
-	Metadata map[string]interface{} `json:"metadata"`
-	// Time to expire a record: TODO: change to timestamp
-	Expiry time.Duration `json:"expiry,omitempty"`
+// Value is an item stored or retrieved from a Store
+// may be used in store implementations to provide metadata
+type Value struct {
+	// Data holds underline struct
+	Data interface{} `json:"data"`
+	// Metadata associated with data for indexing
+	Metadata metadata.Metadata `json:"metadata"`
 }