lib: improve error handling for datastore notifications

Signed-off-by: Christian Hopps <chopps@labn.net>

1 files changed, 87 insertions, 61 deletions

diff --git a/lib/northbound_notif.c b/lib/northbound_notif.c
index b75c86561..10a81d05f 100644
--- a/lib/northbound_notif.c
+++ b/lib/northbound_notif.c
@@ -480,87 +480,96 @@ static struct op_changes_group *op_changes_group_next(void)
 /* Query for changes and notify */
 /* ---------------------------- */
 
+static void timer_walk_abort(struct nb_notif_walk_args *args);
 static void timer_walk_continue(struct event *event);
+static void timer_walk_done(struct nb_notif_walk_args *args);
+
+static struct op_change *__next_change(struct op_changes_group *group)
+{
+	struct op_change *next = RB_NEXT(op_changes, group->cur_change);
+
+	/* Remove and free current so retry works */
+	RB_REMOVE(op_changes, group->cur_changes, group->cur_change);
+	op_change_free(group->cur_change);
+	return next;
+}
+
+static struct op_changes_group *__next_group(struct op_changes_group *group)
+{
+	__dbg("done with oper-path collection for group");
+	op_changes_group_free(group);
+	return op_changes_group_next();
+}
 
 static enum nb_error oper_walk_done(const struct lyd_node *tree, void *arg, enum nb_error ret)
 {
 	struct nb_notif_walk_args *args = arg;
 	struct op_changes_group *group = args->group;
 	const char *path = group->cur_change->path;
-	const char *op = group->cur_changes == &group->adds ? "add" : "delete";
 
 	/* we don't send batches when yielding as we need completed edit in any patch */
 	assert(ret != NB_YIELD);
 
-	nb_notif_walk = NULL;
-
 	if (ret == NB_ERR_NOT_FOUND) {
 		__dbg("Path not found while walking oper tree: %s", path);
-		XFREE(MTYPE_NB_NOTIF_WALK_ARGS, args);
-		return ret;
-	}
-	/* Something else went wrong with the walk */
-	if (ret != NB_OK) {
+		ret = NB_OK;
+	} else if (ret != NB_OK) {
 error:
-		__log_err("Error notifying for datastore change on path: %s: %s", path,
-			  nb_err_name(ret));
-		XFREE(MTYPE_NB_NOTIF_WALK_ARGS, args);
-		/* XXX Need to inform mgmtd/front-ends things are out-of-sync */
-		return ret;
-	}
-
-	__dbg("done with oper-path collection for %s path: %s", op, path);
-
-	/* Do we need this? */
-	while (tree->parent)
-		tree = lyd_parent(tree);
-
-	/* Send the add (replace) notification */
-	if (mgmt_be_send_ds_replace_notification(path, tree)) {
-		ret = NB_ERR;
-		goto error;
+		__log_err("Error notifying for datastore path: %s: %s", path, nb_err_name(ret));
+
+		timer_walk_abort(args);
+		goto done;
+	} else {
+		__dbg("Done with oper-path collection for path: %s", path);
+
+		/* Do we need this? */
+		while (tree->parent)
+			tree = lyd_parent(tree);
+
+		/* Send the add (replace) notification */
+		if (mgmt_be_send_ds_replace_notification(path, tree)) {
+			__log_err("Error sending notification message for path: %s", path);
+			ret = NB_ERR;
+			goto error;
+		}
 	}
 
 	/*
-	 * Advance to next change (either dels or adds or both).
+	 * Advance to next change.
 	 */
 
-	group->cur_change = RB_NEXT(op_changes, group->cur_change);
+	group->cur_change = __next_change(group);
 	if (!group->cur_change) {
-		__dbg("done with oper-path collection for group");
-		op_changes_group_free(group);
-
-		group = op_changes_group_next();
-		args->group = group;
-		if (!group) {
-			__dbg("done with ALL oper-path collection for notification");
-			XFREE(MTYPE_NB_NOTIF_WALK_ARGS, args);
+		args->group = __next_group(group);
+		if (!args->group) {
+			timer_walk_done(args);
 			goto done;
 		}
 	}
 
+	/* Run next walk after giving other events a shot to run */
 	event_add_timer_msec(nb_notif_master, timer_walk_continue, args, 0, &nb_notif_timer);
 done:
 	/* Done with current walk and scheduled next one if there is more */
 	nb_notif_walk = NULL;
 
-	return NB_OK;
+	return ret;
 }
 
-static LY_ERR nb_notify_delete_changes(struct nb_notif_walk_args *args)
+static int nb_notify_delete_changes(struct nb_notif_walk_args *args)
 {
 	struct op_changes_group *group = args->group;
-	LY_ERR err;
 
 	group->cur_change = RB_MIN(op_changes, group->cur_changes);
 	while (group->cur_change) {
-		err = mgmt_be_send_ds_delete_notification(group->cur_change->path);
-		assert(err == LY_SUCCESS); /* XXX */
-
-		group->cur_change = RB_NEXT(op_changes, group->cur_change);
+		if (mgmt_be_send_ds_delete_notification(group->cur_change->path)) {
+			__log_err("Error sending delete notification message for path: %s",
+				  group->cur_change->path);
+			return 1;
+		}
+		group->cur_change = __next_change(group);
 	}
-
-	return LY_SUCCESS;
+	return 0;
 }
 
 static void timer_walk_continue(struct event *event)
@@ -568,15 +577,17 @@ static void timer_walk_continue(struct event *event)
 	struct nb_notif_walk_args *args = EVENT_ARG(event);
 	struct op_changes_group *group = args->group;
 	const char *path;
-	LY_ERR err;
+	int ret;
 
 	/*
 	 * Notify about deletes until we have add changes to collect.
 	 */
 	while (group->cur_changes == &group->dels) {
-		err = nb_notify_delete_changes(args);
-		assert(err == LY_SUCCESS);  /* XXX */
-		assert(!group->cur_change); /* we send all the deletes in one message */
+		ret = nb_notify_delete_changes(args);
+		if (ret) {
+			timer_walk_abort(args);
+			return;
+		}
 
 		/* after deletes advance to adds */
 		group->cur_changes = &group->adds;
@@ -584,14 +595,9 @@ static void timer_walk_continue(struct event *event)
 		if (group->cur_change)
 			break;
 
-		__dbg("done with oper-path change group");
-		op_changes_group_free(group);
-
-		group = op_changes_group_next();
-		args->group = group;
-		if (!group) {
-			__dbg("done with ALL oper-path changes");
-			XFREE(MTYPE_NB_NOTIF_WALK_ARGS, args);
+		args->group = __next_group(group);
+		if (!args->group) {
+			timer_walk_done(args);
 			return;
 		}
 	}
@@ -621,6 +627,22 @@ static void timer_walk_start(struct event *event)
 	timer_walk_continue(event);
 }
 
+static void timer_walk_abort(struct nb_notif_walk_args *args)
+{
+	__dbg("Failed notifying datastore changes, will retry");
+
+	__dbg("oper-state notify setting retry timer to fire in: %d msec ", NB_NOTIF_TIMER_MSEC);
+	event_add_timer_msec(nb_notif_master, timer_walk_continue, args, NB_NOTIF_TIMER_MSEC,
+			     &nb_notif_timer);
+}
+
+static void timer_walk_done(struct nb_notif_walk_args *args)
+{
+	__dbg("Finished notifying for all datastore changes");
+	assert(!args->group);
+	XFREE(MTYPE_NB_NOTIF_WALK_ARGS, args);
+}
+
 static void nb_notif_set_walk_timer(void)
 {
 	if (nb_notif_walk) {
@@ -659,19 +681,23 @@ void nb_notif_init(struct event_loop *tm)
 
 void nb_notif_terminate(void)
 {
-	struct nb_notif_walk_args *args;
+	struct nb_notif_walk_args *args = nb_notif_timer ? EVENT_ARG(nb_notif_timer) : NULL;
 	struct op_changes_group *group;
 
+	__dbg("terminating: timer: %p timer arg: %p walk %p", nb_notif_timer, args, nb_notif_walk);
+
 	EVENT_OFF(nb_notif_timer);
 
 	if (nb_notif_walk) {
-		nb_oper_cancel_walk(nb_notif_walk);
-		/* need to free the group that's in the walk */
+		/* Grab walk args from walk if active. */
 		args = nb_oper_walk_finish_arg(nb_notif_walk);
-		if (args)
-			op_changes_group_free(args->group);
+		nb_oper_cancel_walk(nb_notif_walk);
 		nb_notif_walk = NULL;
 	}
+	if (args) {
+		op_changes_group_free(args->group);
+		XFREE(MTYPE_NB_NOTIF_WALK_ARGS, args);
+	}
 
 	while ((group = op_changes_group_next()))
 		op_changes_group_free(group);