From 06a118826746c0a8b69bbf4069f2c9b9b4afa37d Mon Sep 17 00:00:00 2001
From: Chris Lu <chris.lu@gmail.com>
Date: Tue, 1 Sep 2020 22:48:36 -0700
Subject: [PATCH] mysql/postgres: support kv operations

---
 .../abstract_sql/abstract_sql_store_kv.go     | 78 ++++++++++++++++++-
 1 file changed, 75 insertions(+), 3 deletions(-)

diff --git a/weed/filer/abstract_sql/abstract_sql_store_kv.go b/weed/filer/abstract_sql/abstract_sql_store_kv.go
index cfffc8918..de7d7b7a5 100644
--- a/weed/filer/abstract_sql/abstract_sql_store_kv.go
+++ b/weed/filer/abstract_sql/abstract_sql_store_kv.go
@@ -2,17 +2,89 @@ package abstract_sql
 
 import (
 	"context"
+	"database/sql"
+	"fmt"
 	"github.com/chrislusf/seaweedfs/weed/filer"
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/util"
 )
 
 func (store *AbstractSqlStore) KvPut(ctx context.Context, key []byte, value []byte) (err error) {
-	return filer.ErrKvNotImplemented
+
+	dirStr, dirHash, name := genDirAndName(key)
+
+	res, err := store.getTxOrDB(ctx).ExecContext(ctx, store.SqlInsert, dirHash, name, dirStr, value)
+	if err != nil {
+		return fmt.Errorf("kv insert: %s", err)
+	}
+
+	// TODO maybe it will throw error before coming here?
+
+	affectedRows, err := res.RowsAffected()
+	if err == nil && affectedRows > 0 {
+		return nil
+	}
+
+	// now the insert failed possibly due to duplication constraints
+	glog.V(1).Infof("kv insert falls back to update: %s", err)
+
+	res, err = store.getTxOrDB(ctx).ExecContext(ctx, store.SqlUpdate, value, dirHash, name, dirStr)
+	if err != nil {
+		return fmt.Errorf("kv upsert: %s", err)
+	}
+
+	_, err = res.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("kv upsert no rows affected: %s", err)
+	}
+	return nil
+
 }
 
 func (store *AbstractSqlStore) KvGet(ctx context.Context, key []byte) (value []byte, err error) {
-	return nil, filer.ErrKvNotImplemented
+
+	dirStr, dirHash, name := genDirAndName(key)
+	row := store.getTxOrDB(ctx).QueryRowContext(ctx, store.SqlFind, dirHash, name, dirStr)
+
+	err = row.Scan(&value)
+
+	if err == sql.ErrNoRows {
+		return nil, filer.ErrKvNotFound
+	}
+
+	if err != nil {
+		return nil, fmt.Errorf("kv get: %v", err)
+	}
+
+	return
 }
 
 func (store *AbstractSqlStore) KvDelete(ctx context.Context, key []byte) (err error) {
-	return filer.ErrKvNotImplemented
+
+	dirStr, dirHash, name := genDirAndName(key)
+
+	res, err := store.getTxOrDB(ctx).ExecContext(ctx, store.SqlDelete, dirHash, name, dirStr)
+	if err != nil {
+		return fmt.Errorf("kv delete: %s", err)
+	}
+
+	_, err = res.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("kv delete %s but no rows affected: %s", err)
+	}
+
+	return nil
+
 }
+
+func genDirAndName(key []byte) (dirStr string, dirHash int64, name string) {
+	for len(key) < 8 {
+		key = append(key, 0)
+	}
+
+	dirHash = int64(util.BytesToUint64(key[:8]))
+	dirStr = string(key[:8])
+	name = string(key[8:])
+
+	return
+}
\ No newline at end of file