Delete inactive function versions at deploy time (#5927)

Author: dsotirho-ucsc

scripts/delete_other_function_versions.py

@@ -0,0 +1,45 @@
+"""
+Delete all published versions of the AWS Lambda function except for the version specified to keep.
+"""
+import argparse
+import logging
+import sys
+
+from azul import (
+    R,
+    config,
+)
+from azul.args import (
+    AzulArgumentHelpFormatter,
+)
+from azul.lambdas import (
+    Lambdas,
+)
+from azul.logging import (
+    configure_script_logging,
+)
+
+log = logging.getLogger(__name__)
+
+
+def main(argv: list[str]):
+    assert config.terraform_component == '', R(
+        'This script cannot be run with a Terraform component selected',
+        config.terraform_component)
+    parser = argparse.ArgumentParser(description=__doc__,
+                                     formatter_class=AzulArgumentHelpFormatter)
+    parser.add_argument('--function-name', '-f',
+                        required=True,
+                        help='The name of the Lambda function')
+    parser.add_argument('--function-version', '-v',
+                        required=True,
+                        help='The Lambda function version to keep')
+    args = parser.parse_args(argv)
+    log.info('Deleting function %r versions other than %r',
+             args.function_name, args.function_version)
+    Lambdas().delete_other_function_versions(args.function_name, args.function_version)
+
+
+if __name__ == '__main__':
+    configure_script_logging(log)
+    main(sys.argv[1:])

src/azul/lambdas.py

@@ -106,14 +106,44 @@ def _lambda(self):
         return aws.lambda_
 
     def list_lambdas(self) -> list[Lambda]:
-        # Note that this method returns the unpublished "$LATEST" version of
+        # Note that this method returns the unpublished version ("$LATEST") of
         # each function.
         return [
             Lambda.from_response(function)
             for response in self._lambda.get_paginator('list_functions').paginate()
             for function in response['Functions']
         ]
 
+    def delete_other_function_versions(self,
+                                       function_name: str,
+                                       keep_version: str) -> None:
+        """
+        Delete all published versions of a Lambda function except for the
+        version specified to keep.
+        Raises an error if the specified version does not exist.
+
+        :param function_name: The fully qualified name of the function
+                              e.g. 'azul-service-dev'
+        :param keep_version: The version of the function to not delete.
+        """
+        paginator = self._lambda.get_paginator('list_versions_by_function')
+        versions = [
+            function['Version']
+            for page in paginator.paginate(FunctionName=function_name)
+            for function in page['Versions']
+            if function['Version'] != '$LATEST'  # unpublished version
+        ]
+        try:
+            versions.remove(keep_version)
+        except ValueError:
+            assert False, R(
+                'Function version not found',
+                function_name, keep_version, versions)
+        for version in versions:
+            log.info('Deleting version %r of %r', version, function_name)
+            self._lambda.delete_function(FunctionName=function_name,
+                                         Qualifier=version)
+
     def manage_lambdas(self, enabled: bool):
         lambda_prefixes = [
             config.qualified_resource_name(lambda_infix)

terraform/api_gateway.tf.json.template.py

@@ -778,6 +778,24 @@ def add_waf_blocked_alarm(resources: JSON) -> JSON:
                 }
                 for app in apps
                 for resource_name in app.chalice.tf_function_resource_names
+            },
+            'terraform_data': {
+                resource_name: {
+                    'triggers_replace': ['${aws_lambda_alias.%s.function_version}' % resource_name],
+                    'provisioner': {
+                        'local-exec': {
+                            # Script deletes any published version *except* the specified one
+                            'command': ' '.join([
+                                'python',
+                                f'{config.project_root}/scripts/delete_other_function_versions.py',
+                                '--function-name ${aws_lambda_alias.%s.function_name}' % resource_name,
+                                '--function-version ${aws_lambda_alias.%s.function_version}' % resource_name
+                            ])
+                        }
+                    }
+                }
+                for app in apps
+                for resource_name in app.chalice.tf_function_resource_names
             }
         }),
         *(