mgmt, lib: implement REPLACE operation

Replace operation removes the current data node configuration and sets
the provided value. As current northbound code works only with one
xpath at a time, the operation only makes sense to clear the config of
a container without deleting it itself. However, the next step is to
allow passing JSON-encoded complex values to northbound operations which
will make replace operation much more useful.

Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>

7 files changed, 69 insertions, 2 deletions

diff --git a/lib/mgmt.proto b/lib/mgmt.proto
index e0b6019d2b..5d83fca347 100644
--- a/lib/mgmt.proto
+++ b/lib/mgmt.proto
@@ -58,6 +58,7 @@ enum CfgDataReqType {
   REMOVE_DATA = 2;
   CREATE_DATA = 3;
   DELETE_DATA = 4;
+  REPLACE_DATA = 5;
 }
 
 message YangCfgDataReq {
diff --git a/lib/mgmt_be_client.c b/lib/mgmt_be_client.c
index 53df191b2c..16aea249a4 100644
--- a/lib/mgmt_be_client.c
+++ b/lib/mgmt_be_client.c
@@ -577,6 +577,7 @@ static int mgmt_be_update_setcfg_in_batch(struct mgmt_be_client *client_ctx,
 			break;
 		case MGMTD__CFG_DATA_REQ_TYPE__SET_DATA:
 		case MGMTD__CFG_DATA_REQ_TYPE__CREATE_DATA:
+		case MGMTD__CFG_DATA_REQ_TYPE__REPLACE_DATA:
 			cfg_chg->operation = NB_OP_MODIFY;
 			break;
 		case MGMTD__CFG_DATA_REQ_TYPE__REQ_TYPE_NONE:
diff --git a/lib/northbound.c b/lib/northbound.c
index 1fd58cf8b0..efbf1bc4bc 100644
--- a/lib/northbound.c
+++ b/lib/northbound.c
@@ -691,7 +691,7 @@ int nb_candidate_edit(struct nb_config *candidate,
 		      const struct yang_data *previous,
 		      const struct yang_data *data)
 {
-	struct lyd_node *dnode, *dep_dnode;
+	struct lyd_node *dnode, *dep_dnode, *old_dnode, *parent;
 	char xpath_edit[XPATH_MAXLEN];
 	char dep_xpath[XPATH_MAXLEN];
 	uint32_t options = 0;
@@ -754,6 +754,41 @@ int nb_candidate_edit(struct nb_config *candidate,
 		}
 		lyd_free_tree(dnode);
 		break;
+	case NB_OP_REPLACE:
+		old_dnode = yang_dnode_get(candidate->dnode, xpath_edit);
+		if (old_dnode) {
+			parent = lyd_parent(old_dnode);
+			lyd_unlink_tree(old_dnode);
+		}
+		err = dnode_create(candidate, xpath_edit, data->value, options,
+				   &dnode);
+		if (!err && dnode && !old_dnode) {
+			/* create dependency if the node didn't exist */
+			nb_node = dnode->schema->priv;
+			if (nb_node->dep_cbs.get_dependency_xpath) {
+				nb_node->dep_cbs.get_dependency_xpath(
+					dnode, dep_xpath);
+
+				err = dnode_create(candidate, dep_xpath, NULL,
+						   LYD_NEW_PATH_UPDATE, NULL);
+				if (err)
+					lyd_free_tree(dnode);
+			}
+		}
+		if (old_dnode) {
+			/* restore original node on error, free it otherwise */
+			if (err) {
+				if (parent)
+					lyd_insert_child(parent, old_dnode);
+				else
+					lyd_insert_sibling(candidate->dnode,
+							   old_dnode, NULL);
+				return err;
+			}
+
+			lyd_free_tree(old_dnode);
+		}
+		break;
 	case NB_OP_MOVE:
 		/* TODO: update configuration. */
 		break;
@@ -775,6 +810,8 @@ const char *nb_operation_name(enum nb_operation operation)
 		return "destroy";
 	case NB_OP_DELETE:
 		return "delete";
+	case NB_OP_REPLACE:
+		return "replace";
 	case NB_OP_MOVE:
 		return "move";
 	}
@@ -786,7 +823,7 @@ bool nb_is_operation_allowed(struct nb_node *nb_node, enum nb_operation oper)
 {
 	if (lysc_is_key(nb_node->snode)) {
 		if (oper == NB_OP_MODIFY || oper == NB_OP_DESTROY
-		    || oper == NB_OP_DELETE)
+		    || oper == NB_OP_DELETE || oper == NB_OP_REPLACE)
 			return false;
 	}
 	return true;
diff --git a/lib/northbound.h b/lib/northbound.h
index ef774fb476..3dd9d09d4a 100644
--- a/lib/northbound.h
+++ b/lib/northbound.h
@@ -723,6 +723,7 @@ enum nb_operation {
 	NB_OP_MODIFY,
 	NB_OP_DESTROY,
 	NB_OP_DELETE,
+	NB_OP_REPLACE,
 	NB_OP_MOVE,
 };
 
diff --git a/lib/vty.c b/lib/vty.c
index 7e856e3741..5f9f0dc243 100644
--- a/lib/vty.c
+++ b/lib/vty.c
@@ -4011,6 +4011,11 @@ int vty_mgmt_send_config_data(struct vty *vty, const char *xpath_base,
 				MGMTD__CFG_DATA_REQ_TYPE__CREATE_DATA;
 			break;
 
+		case NB_OP_REPLACE:
+			cfg_req[indx].req_type =
+				MGMTD__CFG_DATA_REQ_TYPE__REPLACE_DATA;
+			break;
+
 		case NB_OP_CREATE:
 		case NB_OP_MODIFY:
 		case NB_OP_MOVE:
diff --git a/mgmtd/mgmt_txn.c b/mgmtd/mgmt_txn.c
index dee75e6586..76681e3076 100644
--- a/mgmtd/mgmt_txn.c
+++ b/mgmtd/mgmt_txn.c
@@ -2072,6 +2072,9 @@ int mgmt_txn_send_set_config_req(uint64_t txn_id, uint64_t req_id,
 		case MGMTD__CFG_DATA_REQ_TYPE__CREATE_DATA:
 			cfg_chg->operation = NB_OP_CREATE_EXCL;
 			break;
+		case MGMTD__CFG_DATA_REQ_TYPE__REPLACE_DATA:
+			cfg_chg->operation = NB_OP_REPLACE;
+			break;
 		case MGMTD__CFG_DATA_REQ_TYPE__REQ_TYPE_NONE:
 		case _MGMTD__CFG_DATA_REQ_TYPE_IS_INT_SIZE:
 		default:
diff --git a/mgmtd/mgmt_vty.c b/mgmtd/mgmt_vty.c
index b12f54ccbe..2591930e4a 100644
--- a/mgmtd/mgmt_vty.c
+++ b/mgmtd/mgmt_vty.c
@@ -212,6 +212,24 @@ DEFPY(mgmt_remove_config_data, mgmt_remove_config_data_cmd,
 	return CMD_SUCCESS;
 }
 
+DEFPY(mgmt_replace_config_data, mgmt_replace_config_data_cmd,
+      "mgmt replace-config WORD$path VALUE",
+      MGMTD_STR
+      "Replace configuration data\n"
+      "XPath expression specifying the YANG data path\n"
+      "Value of the data to set\n")
+{
+
+	strlcpy(vty->cfg_changes[0].xpath, path,
+		sizeof(vty->cfg_changes[0].xpath));
+	vty->cfg_changes[0].value = value;
+	vty->cfg_changes[0].operation = NB_OP_REPLACE;
+	vty->num_cfg_changes = 1;
+
+	vty_mgmt_send_config_data(vty, NULL, false);
+	return CMD_SUCCESS;
+}
+
 DEFPY(show_mgmt_get_config, show_mgmt_get_config_cmd,
       "show mgmt get-config [candidate|operational|running]$dsname WORD$path",
       SHOW_STR MGMTD_STR
@@ -565,6 +583,7 @@ void mgmt_vty_init(void)
 	install_element(CONFIG_NODE, &mgmt_set_config_data_cmd);
 	install_element(CONFIG_NODE, &mgmt_delete_config_data_cmd);
 	install_element(CONFIG_NODE, &mgmt_remove_config_data_cmd);
+	install_element(CONFIG_NODE, &mgmt_replace_config_data_cmd);
 	install_element(CONFIG_NODE, &mgmt_load_config_cmd);
 	install_element(CONFIG_NODE, &mgmt_save_config_cmd);
 	install_element(CONFIG_NODE, &mgmt_rollback_cmd);