Decouple region support from CLI release

Remove the constant variable and move the content to a file. This file will be uploaded to official S3 buckets during CLI release and/or region expansion.

If the file in S3 is not accessible, the code falls back to the local file. The file in S3 is not accessible when we are developing new versions or network access is limited

Signed-off-by: Hanwen <[email protected]>

cli/src/pcluster/api/controllers/common.py

@@ -29,22 +29,26 @@
 )
 from pcluster.aws.common import BadRequestError, LimitExceededError, StackNotFoundError, get_region
 from pcluster.config.common import AllValidatorsSuppressor, TypeMatchValidatorsSuppressor, ValidatorSuppressor
-from pcluster.constants import SUPPORTED_REGIONS, UNSUPPORTED_OPERATIONS_MAP, Operation
+from pcluster.constants import UNSUPPORTED_OPERATIONS_MAP, Operation
 from pcluster.models.cluster import Cluster
 from pcluster.models.common import BadRequest, Conflict, LimitExceeded, NotFound, parse_config
-from pcluster.utils import get_installed_version, to_utc_datetime
+from pcluster.utils import get_installed_version, retrieve_supported_regions, to_utc_datetime
 
 LOGGER = logging.getLogger(__name__)
 
 
 def _set_region(region):
     if not region:
         raise BadRequestException("region needs to be set")
-    if region not in SUPPORTED_REGIONS:
-        raise BadRequestException(f"invalid or unsupported region '{region}'")
-
+    region_backup = os.environ.get("AWS_DEFAULT_REGION")
     LOGGER.info("Setting AWS Region to %s", region)
     os.environ["AWS_DEFAULT_REGION"] = region
+    if region not in retrieve_supported_regions():
+        if region_backup:
+            os.environ["AWS_DEFAULT_REGION"] = region_backup
+        else:
+            del os.environ["AWS_DEFAULT_REGION"]
+        raise BadRequestException(f"invalid or unsupported region '{region}'")
 
 
 def configure_aws_region_from_config(region: Union[None, str], config_str: str):

cli/src/pcluster/cli/commands/configure/utils.py

@@ -19,7 +19,7 @@
 
 from pcluster.aws.aws_api import AWSApi
 from pcluster.aws.common import AWSClientError
-from pcluster.constants import SUPPORTED_REGIONS
+from pcluster.utils import retrieve_supported_regions
 
 LOGGER = logging.getLogger(__name__)
 
@@ -201,7 +201,9 @@ def get_rows_and_header(items):
 def get_regions():
     ec2 = boto3.client("ec2")
     regions = ec2.describe_regions().get("Regions")
-    regions = [region.get("RegionName") for region in regions if region.get("RegionName") in SUPPORTED_REGIONS]
+    regions = [
+        region.get("RegionName") for region in regions if region.get("RegionName") in retrieve_supported_regions()
+    ]
     regions.sort()
     return regions
 

cli/src/pcluster/constants.py

@@ -198,35 +198,6 @@
 
 PCLUSTER_S3_BUCKET_VERSION = "v1"
 
-SUPPORTED_REGIONS = [
-    "af-south-1",
-    "ap-east-1",
-    "ap-northeast-1",
-    "ap-northeast-2",
-    "ap-south-1",
-    "ap-southeast-1",
-    "ap-southeast-2",
-    "ca-central-1",
-    "cn-north-1",
-    "cn-northwest-1",
-    "eu-central-1",
-    "eu-north-1",
-    "eu-south-1",
-    "eu-west-1",
-    "eu-west-2",
-    "eu-west-3",
-    "il-central-1",
-    "me-south-1",
-    "sa-east-1",
-    "us-east-1",
-    "us-east-2",
-    "us-iso-east-1",
-    "us-isob-east-1",
-    "us-gov-east-1",
-    "us-gov-west-1",
-    "us-west-1",
-    "us-west-2",
-]
 
 # see https://docs.aws.amazon.com/cdk/v2/guide/getting_started.html
 NODEJS_MIN_VERSION = "10.13.0"

cli/src/pcluster/resources/supported-regions

@@ -0,0 +1,27 @@
+af-south-1
+ap-east-1
+ap-northeast-1
+ap-northeast-2
+ap-south-1
+ap-southeast-1
+ap-southeast-2
+ca-central-1
+cn-north-1
+cn-northwest-1
+eu-central-1
+eu-north-1
+eu-south-1
+eu-west-1
+eu-west-2
+eu-west-3
+il-central-1
+me-south-1
+sa-east-1
+us-east-1
+us-east-2
+us-iso-east-1
+us-isob-east-1
+us-gov-east-1
+us-gov-west-1
+us-west-1
+us-west-2

cli/src/pcluster/utils.py

@@ -20,13 +20,16 @@
 import string
 import sys
 import time
+import urllib
 import zipfile
 from concurrent.futures import ThreadPoolExecutor
 from io import BytesIO
 from shlex import quote
 from typing import Callable, NoReturn
+from urllib.error import URLError
 from urllib.parse import urlparse
 
+import boto3
 import dateutil.parser
 import pkg_resources
 import yaml
@@ -558,3 +561,21 @@ async def wrapper(self, *args, **kwargs):
             )
 
         return wrapper
+
+
+def retrieve_supported_regions():
+    """Retrieve the list of supported regions."""
+    if not hasattr(retrieve_supported_regions, "cache"):
+        region = boto3.Session().region_name or "us-east-1"
+        try:
+            url = "https://{region}-aws-parallelcluster.s3.{region}.{aws_domain}/supported-regions".format(
+                region=region,
+                aws_domain=get_partition(region),
+            )
+            with urllib.request.urlopen(url) as f:  # nosec B310 nosemgrep
+                retrieve_supported_regions.cache = f.read().decode("utf-8").split("\n")
+        except URLError:
+            # When the file is not found on the URL, use local file. This is useful when developing new versions.
+            with open(pkg_resources.resource_filename(__name__, "/resources/supported-regions"), encoding="utf-8") as f:
+                retrieve_supported_regions.cache = f.read().split("\n")
+    return retrieve_supported_regions.cache

cli/src/pcluster/validators/cluster_validators.py

@@ -36,7 +36,6 @@
     RETAIN_POLICY,
     SCHEDULERS_SUPPORTING_IMDS_SECURED,
     SUPPORTED_OSES,
-    SUPPORTED_REGIONS,
     SUPPORTED_SCHEDULERS,
 )
 from pcluster.launch_template_utils import _LaunchTemplateBuilder
@@ -45,6 +44,7 @@
     get_supported_os_for_architecture,
     get_supported_os_for_scheduler,
     remove_none_values,
+    retrieve_supported_regions,
 )
 from pcluster.validators.common import FailureLevel, Validator
 
@@ -117,7 +117,7 @@ class RegionValidator(Validator):
     """Region validator."""
 
     def _validate(self, region):
-        if region not in SUPPORTED_REGIONS:
+        if region not in retrieve_supported_regions():
             self._add_failure(
                 f"Region '{region}' is not yet officially supported by ParallelCluster", FailureLevel.ERROR
             )