box.watch_once()

box.watch_once(key, func)¶

Returns the current value of a given notification key. The function can be used as an alternative to box.watch() when the caller only needs the current value without subscribing to future changes.

Parameters:	key (string) – key name
Return:	the key value

To read more about watchers, see the Event watchers section.

Example:

-- Broadcast value 42 for the 'foo' key.
box.broadcast('foo', 42)

-- Get the value of this key
tarantool> box.watch_once('foo')
---
- 42
...

-- Non-existent keys' values are empty
tarantool> box.watch_once('none')
---
...