aws_ssm - Refactor boto3 client initialization (#1663)

aws_ssm - Refactor boto3 client initialization

Depends-On: ansible/ansible-zuul-jobs#1748
SUMMARY
Move the boto3 client initialization into a consistent point (rather than initializing them on the fly)
ISSUE TYPE

Feature Pull Request

COMPONENT NAME
aws_ssm
ADDITIONAL INFORMATION
In preparation for further refactoring and using ansible-collections/amazon.aws#1340

Reviewed-by: Markus Bergholz <[email protected]>

changelogs/fragments/1663-aws_ssm-client.yml

@@ -0,0 +1,2 @@
+minor_changes:
+- aws_ssm - refactor boto3 client initialization (https://github.com/ansible-collections/community.aws/pull/1663).

plugins/connection/aws_ssm.py

@@ -298,6 +298,7 @@ class Connection(ConnectionBase):
     has_pipelining = False
     is_windows = False
     _client = None
+    _s3_client = None
     _session = None
     _stdout = None
     _session_id = ''
@@ -323,6 +324,30 @@ def _vvv(self, message):
     def _vvvv(self, message):
         self._display(display.vvvv, message)
 
+    def _init_clients(self):
+        self._vvvv("INITIALIZE BOTO3 CLIENTS")
+        profile_name = self.get_option('profile') or ''
+        region_name = self.get_option('region')
+
+        # The SSM Boto client, currently used to initiate and manage the session
+        # Note: does not handle the actual SSM session traffic
+        self._vvvv("SETUP BOTO3 CLIENTS: SSM")
+        ssm_client = self._get_boto_client('ssm', region_name=region_name, profile_name=profile_name)
+        self._client = ssm_client
+
+        region_name = self.get_option('region') or 'us-east-1'
+        self._vvvv("SETUP BOTO3 CLIENTS: S3 (tmp)")
+        tmp_s3_client = self._get_boto_client('s3', region_name=region_name, profile_name=profile_name)
+        # Fetch the location of the bucket so we can open a client against the 'right' endpoint
+        bucket_location = tmp_s3_client.get_bucket_location(
+            Bucket=(self.get_option('bucket_name')),
+        )
+        bucket_region = bucket_location['LocationConstraint']
+        # This is the S3 client we'll really be using
+        self._vvvv(f"SETUP BOTO3 CLIENTS: S3 - {bucket_region}")
+        s3_bucket_client = self._get_boto_client('s3', region_name=bucket_region, profile_name=profile_name)
+        self._s3_client = s3_bucket_client
+
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
 
@@ -372,27 +397,26 @@ def start_session(self):
         if not os.path.exists(to_bytes(executable, errors='surrogate_or_strict')):
             raise AnsibleError(f"failed to find the executable specified {executable}.")
 
-        profile_name = self.get_option('profile') or ''
-        region_name = self.get_option('region')
-        ssm_parameters = dict()
-        client = self._get_boto_client('ssm', region_name=region_name, profile_name=profile_name)
-        self._client = client
+        self._init_clients()
+
         self._vvvv(f"START SSM SESSION: {self.instance_id}")
-        start_session_args = dict(Target=self.instance_id, Parameters=ssm_parameters)
+        start_session_args = dict(Target=self.instance_id, Parameters={})
         document_name = self.get_option('ssm_document')
         if document_name is not None:
             start_session_args['DocumentName'] = document_name
-        response = client.start_session(**start_session_args)
+        response = self._client.start_session(**start_session_args)
         self._session_id = response['SessionId']
 
+        region_name = self.get_option('region')
+        profile_name = self.get_option('profile') or ''
         cmd = [
             executable,
             json.dumps(response),
             region_name,
             "StartSession",
             profile_name,
             json.dumps({"Target": self.instance_id}),
-            client.meta.endpoint_url,
+            self._client.meta.endpoint_url,
         ]
 
         self._vvvv(f"SSM COMMAND: {to_text(cmd)}")
@@ -650,14 +674,7 @@ def _flush_stderr(self, session_process):
     def _get_url(self, client_method, bucket_name, out_path, http_method, profile_name, extra_args=None):
         ''' Generate URL for get_object / put_object '''
 
-        region_name = self.get_option('region') or 'us-east-1'
-
-        bucket_location = self._get_boto_client('s3', region_name=region_name, profile_name=profile_name).get_bucket_location(
-            Bucket=(self.get_option('bucket_name')),
-        )
-        bucket_region_name = bucket_location['LocationConstraint']
-
-        client = self._get_boto_client('s3', region_name=bucket_region_name, profile_name=profile_name)
+        client = self._s3_client
         params = {'Bucket': bucket_name, 'Key': out_path}
         if extra_args is not None:
             params.update(extra_args)
@@ -731,7 +748,7 @@ def _file_transport_command(self, in_path, out_path, ssm_action):
             get_command = "curl '%s' -o '%s'" % (
                 self._get_url('get_object', self.get_option('bucket_name'), s3_path, 'GET', profile_name), out_path)
 
-        client = self._get_boto_client('s3', profile_name=profile_name)
+        client = self._s3_client
         if ssm_action == 'get':
             (returncode, stdout, stderr) = self.exec_command(put_command, in_data=None, sudoable=False)
             with open(to_bytes(out_path, errors='surrogate_or_strict'), 'wb') as data: