SNC-15879 No error "% Error: Invalid image URL" when attempt to "image set-default" with an invalid image (sonic-net#51)

* Assigning timestamp values and ifnot present then returning empty

* Retracking data type for timestamp and using dbmaps for fetching values

Author: ViramShah91

models/yang/annotations/openconfig-image-management-annot.yang

@@ -102,22 +102,22 @@ module openconfig-image-management-annot {
 
     deviation /oc-img-mgmt:image-management/oc-img-mgmt:install/oc-img-mgmt:state/oc-img-mgmt:transfer-start-time {
       deviate add {
-        sonic-ext:field-name "transfer_task_start_time";
+        sonic-ext:field-transformer "transfer_start_time_xfmr";
       }
     }
     deviation /oc-img-mgmt:image-management/oc-img-mgmt:install/oc-img-mgmt:state/oc-img-mgmt:transfer-end-time {
       deviate add {
-        sonic-ext:field-name "transfer_task_end_time";
+        sonic-ext:field-transformer "transfer_end_time_xfmr";
       }
     }
     deviation /oc-img-mgmt:image-management/oc-img-mgmt:install/oc-img-mgmt:state/oc-img-mgmt:install-start-time {
       deviate add {
-        sonic-ext:field-name "install_task_start_time";
+        sonic-ext:field-transformer "install_start_time_xfmr";
       }
     }
     deviation /oc-img-mgmt:image-management/oc-img-mgmt:install/oc-img-mgmt:state/oc-img-mgmt:install-end-time {
       deviate add {
-        sonic-ext:field-name "install_task_end_time";
+        sonic-ext:field-transformer "install_end_time_xfmr";
       }
     }
 

translib/transformer/xfmr_image_mgmt.go

@@ -38,6 +38,10 @@ func init() {
 	XlateFuncBind("DbToYang_image_table_key_xfmr", DbToYang_image_table_key_xfmr)
 	XlateFuncBind("YangToDb_image_global_key_xfmr", YangToDb_image_global_key_xfmr)
 	XlateFuncBind("DbToYang_image_name_xfmr", DbToYang_image_name_xfmr)
+	XlateFuncBind("DbToYang_transfer_start_time_xfmr", DbToYang_transfer_start_time_xfmr)
+	XlateFuncBind("DbToYang_transfer_end_time_xfmr", DbToYang_transfer_end_time_xfmr)
+	XlateFuncBind("DbToYang_install_start_time_xfmr", DbToYang_install_start_time_xfmr)
+	XlateFuncBind("DbToYang_install_end_time_xfmr", DbToYang_install_end_time_xfmr)
 }
 
 var DbToYang_image_name_xfmr FieldXfmrDbtoYang = func(inParams XfmrParams) (map[string]interface{}, error) {
@@ -51,6 +55,79 @@ var DbToYang_image_name_xfmr FieldXfmrDbtoYang = func(inParams XfmrParams) (map[
 	return res_map, nil
 }
 
+func getDBValuesTime(inParams XfmrParams, varName string) (string, error) {
+	if varName == "" {
+		return "", errors.New("Invalid inParams")
+	}
+	data := (*inParams.dbDataMap)[inParams.curDb]
+	imgTbl := data["IMAGE_GLOBAL"]
+	if _, ok := imgTbl[inParams.key]; !ok {
+		return "", errors.New("Key not present in Image Global table")
+	}
+	imgKey := imgTbl[inParams.key]
+	timeStamp, ok := imgKey.Field[varName]
+	if !ok {
+		return "", errors.New("Field not present in Image Global Table")
+	}
+	return timeStamp, nil
+}
+
+var DbToYang_transfer_start_time_xfmr FieldXfmrDbtoYang = func(inParams XfmrParams) (map[string]interface{}, error) {
+
+	res_map := make(map[string]interface{})
+	value, err := getDBValuesTime(inParams, "transfer_task_start_time")
+	if err != nil {
+		return nil, err
+	}
+	if value == "0" {
+		return nil, err
+	}
+	res_map["transfer-start-time"] = value
+	return res_map, nil
+}
+
+var DbToYang_transfer_end_time_xfmr FieldXfmrDbtoYang = func(inParams XfmrParams) (map[string]interface{}, error) {
+
+	res_map := make(map[string]interface{})
+	value, err := getDBValuesTime(inParams, "transfer_task_end_time")
+	if err != nil {
+		return nil, err
+	}
+	if value == "0" {
+		return nil, err
+	}
+	res_map["transfer-end-time"] = value
+	return res_map, nil
+}
+
+var DbToYang_install_start_time_xfmr FieldXfmrDbtoYang = func(inParams XfmrParams) (map[string]interface{}, error) {
+
+	res_map := make(map[string]interface{})
+	value, err := getDBValuesTime(inParams, "install_task_start_time")
+	if err != nil {
+		return nil, err
+	}
+	if value == "0" {
+		return nil, err
+	}
+	res_map["install-start-time"] = value
+	return res_map, nil
+}
+
+var DbToYang_install_end_time_xfmr FieldXfmrDbtoYang = func(inParams XfmrParams) (map[string]interface{}, error) {
+
+	res_map := make(map[string]interface{})
+	value, err := getDBValuesTime(inParams, "install_task_end_time")
+	if err != nil {
+		return nil, err
+	}
+	if value == "0" {
+		return nil, err
+	}
+	res_map["install-end-time"] = value
+	return res_map, nil
+}
+
 var YangToDb_image_table_key_xfmr KeyXfmrYangToDb = func(inParams XfmrParams) (string, error) {
 
 	var err error