[UX] Support checking user specified cloud(s) with sky check from CLI

sky/check.py

@@ -10,10 +10,20 @@
 
 
 # TODO(zhwu): add check for a single cloud to improve performance
-def check(quiet: bool = False, verbose: bool = False) -> None:
+def check(
+    quiet: bool = False,
+    verbose: bool = False,
+    user_specified_clouds: Optional[Tuple[str]] = None,
+) -> None:
     echo = (lambda *_args, **_kwargs: None) if quiet else click.echo
     echo('Checking credentials to enable clouds for SkyPilot.')
 
+    user_specified_clouds_set = set()
+    if user_specified_clouds is not None:
+        for cloud in user_specified_clouds:
+            clouds.CLOUD_REGISTRY.from_str(cloud)  # verify cloud
+            user_specified_clouds_set.add(cloud.lower())
+
     enabled_clouds = []
 
     def check_one_cloud(cloud_tuple: Tuple[str, clouds.Cloud]) -> None:
@@ -42,7 +52,10 @@ def check_one_cloud(cloud_tuple: Tuple[str, clouds.Cloud]) -> None:
     clouds_to_check.append(('Cloudflare, for R2 object store', cloudflare))
 
     for cloud_tuple in sorted(clouds_to_check):
-        check_one_cloud(cloud_tuple)
+        cloud_repr = cloud_tuple[0].lower()
+        if (user_specified_clouds is None or
+                cloud_repr in user_specified_clouds_set):
+            check_one_cloud(cloud_tuple)
 
     # Cloudflare is not a real cloud in clouds.CLOUD_REGISTRY, and should not be
     # inserted into the DB (otherwise `sky launch` and other code would error

sky/cli.py

@@ -3452,13 +3452,14 @@ def tpunode(cluster: str, yes: bool, port_forward: Optional[List[int]],
 
 
 @cli.command()
+@click.argument('user_specified_clouds', required=False, type=str, nargs=-1)
 @click.option('--verbose',
               '-v',
               is_flag=True,
               default=False,
               help='Show the activated account for each cloud.')
 @usage_lib.entrypoint
-def check(verbose: bool):
+def check(user_specified_clouds: Tuple[str], verbose: bool):
     """Check which clouds are available to use.
 
     This checks access credentials for all clouds supported by SkyPilot. If a
@@ -3468,7 +3469,10 @@ def check(verbose: bool):
     The enabled clouds are cached and form the "search space" to be considered
     for each task.
     """
-    sky_check.check(verbose=verbose)
+    user_specified_clouds_arg = user_specified_clouds if len(
+        user_specified_clouds) > 0 else None
+    sky_check.check(verbose=verbose,
+                    user_specified_clouds=user_specified_clouds_arg)
 
 
 @cli.command()