Timer: Allow setting a new interval in reset

Signed-off-by: Mathias L. Baumann <mathias.baumann@frequenz.com>

RELEASE_NOTES.md

@@ -1,5 +1,9 @@
 # Frequenz channels Release Notes
 
+## New Features
+
+- `Timer.reset()` now supports setting the interval and will restart the timer with the new interval.
+
 ## Bug Fixes
 
 - `FileWatcher`: Fixed `ready()` method to return False when an error occurs. Before this fix, `select()` (and other code using `ready()`) never detected the `FileWatcher` was stopped and the `select()` loop was continuously waking up to inform the receiver was ready.

src/frequenz/channels/timer.py

@@ -586,7 +586,12 @@ def is_running(self) -> bool:
         """Whether the timer is running."""
         return not self._stopped
 
-    def reset(self, *, start_delay: timedelta = timedelta(0)) -> None:
+    def reset(
+        self,
+        *,
+        interval: timedelta | None = None,
+        start_delay: timedelta = timedelta(0),
+    ) -> None:
         """Reset the timer to start timing from now (plus an optional delay).
 
         If the timer was stopped, or not started yet, it will be started.
@@ -595,6 +600,8 @@ def reset(self, *, start_delay: timedelta = timedelta(0)) -> None:
         more details.
 
         Args:
+            interval: The new interval between ticks. If `None`, the current
+                interval is kept.
             start_delay: The delay before the timer should start. This has microseconds
                 resolution, anything smaller than a microsecond means no delay.
 
@@ -607,6 +614,9 @@ def reset(self, *, start_delay: timedelta = timedelta(0)) -> None:
         if start_delay_ms < 0:
             raise ValueError(f"`start_delay` can't be negative, got {start_delay}")
 
+        if interval is not None:
+            self._interval = _to_microseconds(interval)
+
         self._next_tick_time = self._now() + start_delay_ms + self._interval
 
         if self.is_running: