Register postgre driver in pkg/event/target (minio#6689)

Commit 5c13765 removed postgre registration triggerd
by the automatic gofmt command but it was the only where pg is registered. This commit
fixes behavior and adds unit tests to check whether postgre & sql are registered or not.

pkg/event/target/mysql_test.go

@@ -0,0 +1,37 @@
+/*
+ * Minio Cloud Storage, (C) 2018 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package target
+
+import (
+	"database/sql"
+	"testing"
+)
+
+// TestPostgreSQLRegistration checks if sql driver
+// is registered and fails otherwise.
+func TestMySQLRegistration(t *testing.T) {
+	var found bool
+	for _, drv := range sql.Drivers() {
+		if drv == "mysql" {
+			found = true
+			break
+		}
+	}
+	if !found {
+		t.Fatal("mysql driver not registered")
+	}
+}

pkg/event/target/postgresql.go

@@ -62,6 +62,8 @@ import (
 	"strings"
 	"time"
 
+	_ "github.com/lib/pq" // Register postgres driver
+
 	"github.com/minio/minio/pkg/event"
 	xnet "github.com/minio/minio/pkg/net"
 )

pkg/event/target/postgresql_test.go

@@ -0,0 +1,37 @@
+/*
+ * Minio Cloud Storage, (C) 2018 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package target
+
+import (
+	"database/sql"
+	"testing"
+)
+
+// TestPostgreSQLRegistration checks if postgres driver
+// is registered and fails otherwise.
+func TestPostgreSQLRegistration(t *testing.T) {
+	var found bool
+	for _, drv := range sql.Drivers() {
+		if drv == "postgres" {
+			found = true
+			break
+		}
+	}
+	if !found {
+		t.Fatal("postgres driver not registered")
+	}
+}