add key/value store service (#36868)

* add key/value store service

* don't export kvStoreSQL, consumers should interact with KVStore & NamespacedKVStore

* add del method, avoid ErrNotFound (#38627)

* switch value column to medium text

Co-authored-by: Alexander Emelin <frvzmb@gmail.com>

pkg/services/sqlstore/migrations/kv_store_mig.go

@@ -0,0 +1,27 @@
+package migrations
+
+import (
+	. "github.com/grafana/grafana/pkg/services/sqlstore/migrator"
+)
+
+func addKVStoreMigrations(mg *Migrator) {
+	kvStoreV1 := Table{
+		Name: "kv_store",
+		Columns: []*Column{
+			{Name: "id", Type: DB_BigInt, Nullable: false, IsPrimaryKey: true, IsAutoIncrement: true},
+			{Name: "org_id", Type: DB_BigInt, Nullable: false},
+			{Name: "namespace", Type: DB_NVarchar, Length: 190, Nullable: false},
+			{Name: "key", Type: DB_NVarchar, Length: 190, Nullable: false},
+			{Name: "value", Type: DB_MediumText, Nullable: false},
+			{Name: "created", Type: DB_DateTime, Nullable: false},
+			{Name: "updated", Type: DB_DateTime, Nullable: false},
+		},
+		Indices: []*Index{
+			{Cols: []string{"org_id", "namespace", "key"}, Type: UniqueIndex},
+		},
+	}
+
+	mg.AddMigration("create kv_store table v1", NewAddTableMigration(kvStoreV1))
+
+	mg.AddMigration("add index kv_store.org_id-namespace-key", NewAddIndexMigration(kvStoreV1, kvStoreV1.Indices[0]))
+}

pkg/services/sqlstore/migrations/migrations.go

@@ -52,6 +52,7 @@ func (*OSSMigrations) AddMigration(mg *Migrator) {
 		addLiveChannelMigrations(mg)
 	}
 	ualert.RerunDashAlertMigration(mg)
+	addKVStoreMigrations(mg)
 }
 
 func addMigrationLogMigrations(mg *Migrator) {