Fix API quota hitting when provisioning many A3 instances

src/dstack/_internal/core/backends/gcp/compute.py

@@ -1,10 +1,12 @@
 import concurrent.futures
 import json
+import threading
 from collections import defaultdict
 from typing import Callable, Dict, List, Literal, Optional, Tuple
 
 import google.api_core.exceptions
 import google.cloud.compute_v1 as compute_v1
+from cachetools import TTLCache, cachedmethod
 from google.cloud import tpu_v2
 from gpuhunt import KNOWN_TPUS
 
@@ -98,6 +100,8 @@ def __init__(self, config: GCPConfig):
         self.resource_policies_client = compute_v1.ResourcePoliciesClient(
             credentials=self.credentials
         )
+        self._extra_subnets_cache_lock = threading.Lock()
+        self._extra_subnets_cache = TTLCache(maxsize=30, ttl=60)
 
     def get_offers(
         self, requirements: Optional[Requirements] = None
@@ -193,9 +197,7 @@ def create_instance(
             config=self.config,
             region=instance_offer.region,
         )
-        extra_subnets = _get_extra_subnets(
-            subnetworks_client=self.subnetworks_client,
-            config=self.config,
+        extra_subnets = self._get_extra_subnets(
             region=instance_offer.region,
             instance_type_name=instance_offer.instance.name,
         )
@@ -769,6 +771,38 @@ def detach_volume(self, volume: Volume, instance_id: str, force: bool = False):
             instance_id,
         )
 
+    @cachedmethod(
+        cache=lambda self: self._extra_subnets_cache,
+        lock=lambda self: self._extra_subnets_cache_lock,
+    )
+    def _get_extra_subnets(
+        self,
+        region: str,
+        instance_type_name: str,
+    ) -> List[Tuple[str, str]]:
+        if self.config.extra_vpcs is None:
+            return []
+        if instance_type_name == "a3-megagpu-8g":
+            subnets_num = 8
+        elif instance_type_name in ["a3-edgegpu-8g", "a3-highgpu-8g"]:
+            subnets_num = 4
+        else:
+            return []
+        extra_subnets = []
+        for vpc_name in self.config.extra_vpcs[:subnets_num]:
+            subnet = gcp_resources.get_vpc_subnet_or_error(
+                subnetworks_client=self.subnetworks_client,
+                vpc_project_id=self.config.vpc_project_id or self.config.project_id,
+                vpc_name=vpc_name,
+                region=region,
+            )
+            vpc_resource_name = gcp_resources.vpc_name_to_vpc_resource_name(
+                project_id=self.config.vpc_project_id or self.config.project_id,
+                vpc_name=vpc_name,
+            )
+            extra_subnets.append((vpc_resource_name, subnet))
+        return extra_subnets
+
 
 def _supported_instances_and_zones(
     regions: List[str],
@@ -843,36 +877,6 @@ def _get_vpc_subnet(
     )
 
 
-def _get_extra_subnets(
-    subnetworks_client: compute_v1.SubnetworksClient,
-    config: GCPConfig,
-    region: str,
-    instance_type_name: str,
-) -> List[Tuple[str, str]]:
-    if config.extra_vpcs is None:
-        return []
-    if instance_type_name == "a3-megagpu-8g":
-        subnets_num = 8
-    elif instance_type_name in ["a3-edgegpu-8g", "a3-highgpu-8g"]:
-        subnets_num = 4
-    else:
-        return []
-    extra_subnets = []
-    for vpc_name in config.extra_vpcs[:subnets_num]:
-        subnet = gcp_resources.get_vpc_subnet_or_error(
-            subnetworks_client=subnetworks_client,
-            vpc_project_id=config.vpc_project_id or config.project_id,
-            vpc_name=vpc_name,
-            region=region,
-        )
-        vpc_resource_name = gcp_resources.vpc_name_to_vpc_resource_name(
-            project_id=config.vpc_project_id or config.project_id,
-            vpc_name=vpc_name,
-        )
-        extra_subnets.append((vpc_resource_name, subnet))
-    return extra_subnets
-
-
 def _get_image_id(instance_type_name: str, cuda: bool) -> str:
     if instance_type_name == "a3-megagpu-8g":
         image_name = "dstack-a3mega-5"