Update synchronized_start_timeout to use nanoseconds

CHANGELOG.md

@@ -9,6 +9,10 @@ use patch releases for compatibility fixes instead.
 
 ## Unreleased
 
+### Fixed
+
+- Update `synchronized_start_timeout` to send nanoseconds to the Beaker server instead of a string.
+
 ## [v1.26.8](https://github.com/allenai/beaker-py/releases/tag/v1.26.8) - 2024-05-01
 
 - Added new fields `JobStatus.ready`, `JobExecution.replica_rank`, and `JobExecution.replica_group_id`.

beaker/data_model/experiment_spec.py

@@ -403,11 +403,11 @@ class TaskSpec(BaseModel, frozen=False):
     Determines if whole experiment should fail if this task failures.
     """
 
-    synchronized_start_timeout: Optional[str] = None
+    synchronized_start_timeout: Optional[int] = None
     """
     If set, jobs in the replicated task will wait to start, up to the specified timeout, 
     until all other jobs are also ready. If the timeout is reached, the job will be canceled.
-    Must be greater than zero and less than or equal to 48 hours.
+    Represented using nanoseconds, must be greater than zero and less than or equal to 48 hours.
     """
 
     @classmethod
@@ -472,6 +472,12 @@ def new(
                 else:
                     constraints = Constraints(cluster=[cluster])
 
+        # Allow setting the timeout using seconds, rather than nanoseconds.
+        synchronized_start_timeout_str = kwargs.pop("synchronized_start_timeout", None)
+        if synchronized_start_timeout_str is not None:
+            synchronized_start_timeout = int(synchronized_start_timeout_str * 1_000_000_000)
+            kwargs["synchronized_start_timeout"] = synchronized_start_timeout
+
         return TaskSpec(
             name=name,
             image=ImageSource(beaker=beaker_image, docker=docker_image),