[UX] Make sky logs <nonexistent job id> not error out. (skypilot-org#1617)

* Make `sky logs <nonexistent job id>` not error out.

* Reformat

Author: concretevitamin

sky/skylet/job_lib.py

@@ -362,17 +362,14 @@ def _get_jobs_by_ids(job_ids: List[int]) -> List[Dict[str, Any]]:
 def update_job_status(job_owner: str,
                       job_ids: List[int],
                       silent: bool = False) -> List[JobStatus]:
-    """Updates and returns the job statuses matching our `JobStatus` semantics
+    """Updates and returns the job statuses matching our `JobStatus` semantics.
 
-    "True" statuses: this function queries `ray job status` and processes
-    those results to match our semantics.
+    This function queries `ray job status` and processes those results to match
+    our semantics.
 
-    This function queries `ray job status` and processes those results to
-    match our semantics.
-
-    Though we update job status actively in ray program and job cancelling,
-    we still need this to handle staleness problem, caused by instance
-    restarting and other corner cases (if any).
+    Though we update job status actively in the generated ray program and
+    during job cancelling, we still need this to handle the staleness problem,
+    caused by instance restarting and other corner cases (if any).
 
     This function should only be run on the remote instance with ray==2.0.1.
     """
@@ -413,7 +410,8 @@ def update_job_status(job_owner: str,
             if status is None:
                 original_status = get_status_no_lock(job_id)
                 status = original_status
-                if not original_status.is_terminal():
+                if (original_status is not None and
+                        not original_status.is_terminal()):
                     # The job may be stale, when the instance is restarted
                     # (the ray redis is volatile). We need to reset the
                     # status of the task to FAILED if its original status
@@ -665,14 +663,12 @@ def tail_logs(cls,
                   job_id: Optional[int],
                   spot_job_id: Optional[int],
                   follow: bool = True) -> str:
+        # pylint: disable=line-too-long
         code = [
-            f'job_id = {job_id} if {job_id} is not None '
-            'else job_lib.get_latest_job_id()',
+            f'job_id = {job_id} if {job_id} is not None else job_lib.get_latest_job_id()',
             'run_timestamp = job_lib.get_run_timestamp(job_id)',
-            (f'log_dir = os.path.join({constants.SKY_LOGS_DIRECTORY!r}, '
-             'run_timestamp)'),
-            (f'log_lib.tail_logs({job_owner!r},'
-             f'job_id, log_dir, {spot_job_id!r}, follow={follow})'),
+            f'log_dir = None if run_timestamp is None else os.path.join({constants.SKY_LOGS_DIRECTORY!r}, run_timestamp)',
+            f'log_lib.tail_logs({job_owner!r}, job_id, log_dir, {spot_job_id!r}, follow={follow})',
         ]
         return cls._build(code)
 

sky/skylet/log_lib.py

@@ -383,14 +383,14 @@ def tail_logs(job_owner: str,
     job_str = f'job {job_id}'
     if spot_job_id is not None:
         job_str = f'spot job {spot_job_id}'
-    logger.debug(f'Tailing logs for job, real job_id {job_id}, spot_job_id '
-                 f'{spot_job_id}.')
-    logger.info(f'{colorama.Fore.YELLOW}Start streaming logs for {job_str}.'
-                f'{colorama.Style.RESET_ALL}')
     if log_dir is None:
         print(f'{job_str.capitalize()} not found (see `sky queue`).',
               file=sys.stderr)
         return
+    logger.debug(f'Tailing logs for job, real job_id {job_id}, spot_job_id '
+                 f'{spot_job_id}.')
+    logger.info(f'{colorama.Fore.YELLOW}Start streaming logs for {job_str}.'
+                f'{colorama.Style.RESET_ALL}')
     log_path = os.path.join(log_dir, 'run.log')
     log_path = os.path.expanduser(log_path)