From 72e64dbf30b94185998c937e5ed31087a51f0013 Mon Sep 17 00:00:00 2001
From: Tatiana Litvinova <litvit@amazon.com>
Date: Wed, 4 Jan 2023 18:24:43 +0100
Subject: [PATCH] Pre-import cdk libraries at the beginning of cluster create
 and update Import of cdk libraries at lambda cold start takes 12 to 16
 seconds, sometimes causing lambda timeout. Importing them in a separate
 thread, started at the beginning of create and update operations and executed
 concurrently with stack validation allows to reduce the time to complete the
 operation.

---
 .../pcluster/api/controllers/import_cdk.py    | 27 +++++++++++++++++++
 cli/src/pcluster/models/cluster.py            |  3 +++
 2 files changed, 30 insertions(+)
 create mode 100644 cli/src/pcluster/api/controllers/import_cdk.py

diff --git a/cli/src/pcluster/api/controllers/import_cdk.py b/cli/src/pcluster/api/controllers/import_cdk.py
new file mode 100644
index 0000000000..4bd503849c
--- /dev/null
+++ b/cli/src/pcluster/api/controllers/import_cdk.py
@@ -0,0 +1,27 @@
+import logging
+import time
+from threading import Thread
+
+LOGGER = logging.getLogger(__name__)
+
+
+def import_cdk():
+    """Import cdk libraries."""
+    LOGGER.info("Start importing")
+    begin = time.time()
+    from aws_cdk.core import App  # noqa: F401 pylint: disable=import-outside-toplevel
+
+    from pcluster.templates.cluster_stack import ClusterCdkStack  # noqa: F401 pylint: disable=import-outside-toplevel
+
+    LOGGER.info("Import complete in %i seconds", time.time() - begin)
+
+
+def start():
+    """
+    Import cdk libraries in a separate thread.
+
+    :return: thread importing cdk libraries
+    """
+    thread = Thread(target=import_cdk)
+    thread.start()
+    return thread
diff --git a/cli/src/pcluster/models/cluster.py b/cli/src/pcluster/models/cluster.py
index 3c92169757..423c2c664c 100644
--- a/cli/src/pcluster/models/cluster.py
+++ b/cli/src/pcluster/models/cluster.py
@@ -29,6 +29,7 @@
 from jinja2.sandbox import SandboxedEnvironment
 from marshmallow import ValidationError
 
+from pcluster.api.controllers.import_cdk import start as start_cdk_import
 from pcluster.api.models import Metadata
 from pcluster.aws.aws_api import AWSApi
 from pcluster.aws.common import AWSClientError, BadRequestError, LimitExceededError, StackNotFoundError, get_region
@@ -352,6 +353,7 @@ def create(
         raises ClusterActionError: in case of generic error
         raises ConfigValidationError: if configuration is invalid
         """
+        start_cdk_import()
         creation_result = None
         artifact_dir_generated = False
         try:
@@ -887,6 +889,7 @@ def update(
         raises ConfigValidationError: if configuration is invalid
         raises ClusterUpdateError: if update is not allowed
         """
+        start_cdk_import()
         try:
             target_config, changes, ignored_validation_failures = self.validate_update_request(
                 target_source_config, validator_suppressors, validation_failure_level, force