pub trait Watch<ChannelSigner: Sign> {
fn watch_channel(
&self,
funding_txo: OutPoint,
monitor: ChannelMonitor<ChannelSigner>
) -> Result<(), ChannelMonitorUpdateErr>;
fn update_channel(
&self,
funding_txo: OutPoint,
update: ChannelMonitorUpdate
) -> Result<(), ChannelMonitorUpdateErr>;
fn release_pending_monitor_events(&self) -> Vec<MonitorEvent>ⓘNotable traits for Vec<u8, A>impl<A> Write for Vec<u8, A> where
A: Allocator, ;
}Expand description
The Watch trait defines behavior for watching on-chain activity pertaining to channels as
blocks are connected and disconnected.
Each channel is associated with a ChannelMonitor. Implementations of this trait are
responsible for maintaining a set of monitors such that they can be updated accordingly as
channel state changes and HTLCs are resolved. See method documentation for specific
requirements.
Implementations must ensure that updates are successfully applied and persisted upon method
completion. If an update fails with a PermanentFailure, then it must immediately shut down
without taking any further action such as persisting the current state.
If an implementation maintains multiple instances of a channel’s monitor (e.g., by storing
backup copies), then it must ensure that updates are applied across all instances. Otherwise, it
could result in a revoked transaction being broadcast, allowing the counterparty to claim all
funds in the channel. See ChannelMonitorUpdateErr for more details about how to handle
multiple instances.
Required methods
fn watch_channel(
&self,
funding_txo: OutPoint,
monitor: ChannelMonitor<ChannelSigner>
) -> Result<(), ChannelMonitorUpdateErr>
fn watch_channel(
&self,
funding_txo: OutPoint,
monitor: ChannelMonitor<ChannelSigner>
) -> Result<(), ChannelMonitorUpdateErr>
Watches a channel identified by funding_txo using monitor.
Implementations are responsible for watching the chain for the funding transaction along
with any spends of outputs returned by get_outputs_to_watch. In practice, this means
calling block_connected and block_disconnected on the monitor.
Note: this interface MUST error with ChannelMonitorUpdateErr::PermanentFailure if
the given funding_txo has previously been registered via watch_channel.
fn update_channel(
&self,
funding_txo: OutPoint,
update: ChannelMonitorUpdate
) -> Result<(), ChannelMonitorUpdateErr>
fn update_channel(
&self,
funding_txo: OutPoint,
update: ChannelMonitorUpdate
) -> Result<(), ChannelMonitorUpdateErr>
Updates a channel identified by funding_txo by applying update to its monitor.
Implementations must call update_monitor with the given update. See
ChannelMonitorUpdateErr for invariants around returning an error.
fn release_pending_monitor_events(&self) -> Vec<MonitorEvent>ⓘNotable traits for Vec<u8, A>impl<A> Write for Vec<u8, A> where
A: Allocator,
fn release_pending_monitor_events(&self) -> Vec<MonitorEvent>ⓘNotable traits for Vec<u8, A>impl<A> Write for Vec<u8, A> where
A: Allocator,
A: Allocator,
Returns any monitor events since the last call. Subsequent calls must only return new events.
Note that after any block- or transaction-connection calls to a ChannelMonitor, no
further events may be returned here until the ChannelMonitor has been fully persisted
to disk.
For details on asynchronous ChannelMonitor updating and returning
MonitorEvent::UpdateCompleted here, see ChannelMonitorUpdateErr::TemporaryFailure.