diff --git a/pkg/simple/client/elasticsearch/interface.go b/pkg/simple/client/elasticsearch/interface.go
index 7f7c93ca9..291a8cc73 100644
--- a/pkg/simple/client/elasticsearch/interface.go
+++ b/pkg/simple/client/elasticsearch/interface.go
@@ -56,15 +56,17 @@ func detectVersionMajor(cfg *Config) error {
 	}
 	if res.IsError() {
 		// Print the response status and error information.
-		return fmt.Errorf("[%s] %s: %s",
-			res.Status(),
-			b["error"].(map[string]interface{})["type"],
-			b["error"].(map[string]interface{})["reason"],
-		)
+		e, _ := b["error"].(map[string]interface{})
+		return fmt.Errorf("[%s] %s: %s", res.Status(), e["type"], e["reason"])
 	}
 
 	// get the major version
-	version := fmt.Sprintf("%v", b["version"].(map[string]interface{})["number"])
-	cfg.VersionMajor = strings.Split(version, ".")[0]
+	version, _ := b["version"].(map[string]interface{})
+	number, _ := version["number"].(string)
+	if number == "" {
+		return fmt.Errorf("failed to detect elastic version number")
+	}
+
+	cfg.VersionMajor = strings.Split(number, ".")[0]
 	return nil
 }
diff --git a/pkg/simple/client/elasticsearch/versions/v5/elasticsearch.go b/pkg/simple/client/elasticsearch/versions/v5/elasticsearch.go
index 9dc395cb2..a66f60c3e 100644
--- a/pkg/simple/client/elasticsearch/versions/v5/elasticsearch.go
+++ b/pkg/simple/client/elasticsearch/versions/v5/elasticsearch.go
@@ -41,11 +41,8 @@ func (e Elastic) Search(body []byte) ([]byte, error) {
 			return nil, err
 		} else {
 			// Print the response status and error information.
-			return nil, fmt.Errorf("[%s] %s: %s",
-				response.Status(),
-				e["error"].(map[string]interface{})["type"],
-				e["error"].(map[string]interface{})["reason"],
-			)
+			e, _ := e["error"].(map[string]interface{})
+			return nil, fmt.Errorf("[%s] %s: %s", response.Status(), e["type"], e["reason"])
 		}
 	}
 
@@ -53,5 +50,6 @@ func (e Elastic) Search(body []byte) ([]byte, error) {
 }
 
 func (e Elastic) GetTotalHitCount(v interface{}) int64 {
-	return int64(v.(float64))
+	f, _ := v.(float64)
+	return int64(f)
 }
diff --git a/pkg/simple/client/elasticsearch/versions/v6/elasticsearch.go b/pkg/simple/client/elasticsearch/versions/v6/elasticsearch.go
index 2919f3788..2c116ed2a 100644
--- a/pkg/simple/client/elasticsearch/versions/v6/elasticsearch.go
+++ b/pkg/simple/client/elasticsearch/versions/v6/elasticsearch.go
@@ -41,11 +41,8 @@ func (e Elastic) Search(body []byte) ([]byte, error) {
 			return nil, err
 		} else {
 			// Print the response status and error information.
-			return nil, fmt.Errorf("[%s] %s: %s",
-				response.Status(),
-				e["error"].(map[string]interface{})["type"],
-				e["error"].(map[string]interface{})["reason"],
-			)
+			e, _ := e["error"].(map[string]interface{})
+			return nil, fmt.Errorf("[%s] %s: %s", response.Status(), e["type"], e["reason"])
 		}
 	}
 
@@ -53,5 +50,6 @@ func (e Elastic) Search(body []byte) ([]byte, error) {
 }
 
 func (e Elastic) GetTotalHitCount(v interface{}) int64 {
-	return int64(v.(float64))
+	f, _ := v.(float64)
+	return int64(f)
 }
diff --git a/pkg/simple/client/elasticsearch/versions/v7/elasticsearch.go b/pkg/simple/client/elasticsearch/versions/v7/elasticsearch.go
index f91a2094c..27634b4ed 100644
--- a/pkg/simple/client/elasticsearch/versions/v7/elasticsearch.go
+++ b/pkg/simple/client/elasticsearch/versions/v7/elasticsearch.go
@@ -42,11 +42,8 @@ func (e Elastic) Search(body []byte) ([]byte, error) {
 			return nil, err
 		} else {
 			// Print the response status and error information.
-			return nil, fmt.Errorf("[%s] %s: %s",
-				response.Status(),
-				e["error"].(map[string]interface{})["type"],
-				e["error"].(map[string]interface{})["reason"],
-			)
+			e, _ := e["error"].(map[string]interface{})
+			return nil, fmt.Errorf("[%s] %s: %s", response.Status(), e["type"], e["reason"])
 		}
 	}
 
@@ -54,5 +51,7 @@ func (e Elastic) Search(body []byte) ([]byte, error) {
 }
 
 func (e Elastic) GetTotalHitCount(v interface{}) int64 {
-	return int64(v.(map[string]interface{})["value"].(float64))
+	m, _ := v.(map[string]interface{})
+	f, _ := m["value"].(float64)
+	return int64(f)
 }