Minor updates to scaffold.py (#4213)

Co-authored-by: Karri Balk <kbalk@users.noreply.github.com>

scripts/scaffold.py

@@ -1,13 +1,20 @@
 #!/usr/bin/env python
-"""This script generates template codes and response body for specified boto3's operation and apply to appropriate files.
+"""Generates template code and response body for specified boto3's operation.
+
 You only have to select service and operation that you want to add.
-This script looks at the botocore's definition file of specified service and operation, and auto-generates codes and reponses.
-Basically, this script supports almost all services, as long as its protocol is `query`, `json` or `rest-json`.
-Event if aws adds new services, this script will work as long as the protocol is known.
+
+This script looks at the botocore's definition file of specified service and
+operation, and auto-generates codes and reponses.
+
+Basically, this script supports almost all services, as long as its
+protocol is `query`, `json` or `rest-json`.  Even if aws adds new
+services, this script will work as long as the protocol is known.
 
 TODO:
-  - This scripts don't generates functions in `responses.py` for `rest-json`, because I don't know the rule of it. want someone fix this.
-  - In some services's operations, this scripts might crash. Make new issue on github then.
+  - This scripts don't generates functions in `responses.py` for
+  `rest-json`, because I don't know the rule of it. want someone fix this.
+  - In some services's operations, this scripts might crash. Make new
+  issue on github then.
 """
 import os
 import re
@@ -19,7 +26,6 @@ import click
 import jinja2
 from prompt_toolkit import prompt
 from prompt_toolkit.completion import WordCompleter
-from prompt_toolkit.shortcuts import print_formatted_text
 
 from botocore import xform_name
 from botocore.session import Session
@@ -27,8 +33,8 @@ import boto3
 
 from moto.core.responses import BaseResponse
 from moto.core import BaseBackend
-from implementation_coverage import get_moto_implementation
 from inflection import singularize
+from implementation_coverage import get_moto_implementation
 
 TEMPLATE_DIR = os.path.join(os.path.dirname(__file__), "./template")
 
@@ -37,16 +43,16 @@ OUTPUT_IGNORED_IN_BACKEND = ["NextMarker"]
 
 
 def print_progress(title, body, color):
-    click.secho(u"\t{}\t".format(title), fg=color, nl=False)
+    click.secho("\t{}\t".format(title), fg=color, nl=False)
     click.echo(body)
 
 
 def select_service_and_operation():
     service_names = Session().get_available_services()
     service_completer = WordCompleter(service_names)
-    service_name = prompt(u"Select service: ", completer=service_completer)
+    service_name = prompt("Select service: ", completer=service_completer)
     if service_name not in service_names:
-        click.secho(u"{} is not valid service".format(service_name), fg="red")
+        click.secho("{} is not valid service".format(service_name), fg="red")
         raise click.Abort()
     moto_client = get_moto_implementation(service_name)
     real_client = boto3.client(service_name, region_name="us-east-1")
@@ -56,11 +62,11 @@ def select_service_and_operation():
     operation_names = [
         xform_name(op) for op in real_client.meta.service_model.operation_names
     ]
-    for op in operation_names:
-        if moto_client and op in dir(moto_client):
-            implemented.append(op)
+    for operation in operation_names:
+        if moto_client and operation in dir(moto_client):
+            implemented.append(operation)
         else:
-            not_implemented.append(op)
+            not_implemented.append(operation)
     operation_completer = WordCompleter(operation_names)
 
     click.echo("==Current Implementation Status==")
@@ -68,7 +74,7 @@ def select_service_and_operation():
         check = "X" if operation_name in implemented else " "
         click.secho("[{}] {}".format(check, operation_name))
     click.echo("=================================")
-    operation_name = prompt(u"Select Operation: ", completer=operation_completer)
+    operation_name = prompt("Select Operation: ", completer=operation_completer)
 
     if operation_name not in operation_names:
         click.secho("{} is not valid operation".format(operation_name), fg="red")
@@ -93,7 +99,7 @@ def get_test_dir(service):
 
 
 def render_template(tmpl_dir, tmpl_filename, context, service, alt_filename=None):
-    is_test = True if "test" in tmpl_dir else False
+    is_test = "test" in tmpl_dir
     rendered = (
         jinja2.Environment(loader=jinja2.FileSystemLoader(tmpl_dir))
         .get_template(tmpl_filename)
@@ -108,14 +114,14 @@ def render_template(tmpl_dir, tmpl_filename, context, service, alt_filename=None
         print_progress("skip creating", filepath, "yellow")
     else:
         print_progress("creating", filepath, "green")
-        with open(filepath, "w") as f:
-            f.write(rendered)
+        with open(filepath, "w") as fhandle:
+            fhandle.write(rendered)
 
 
 def append_mock_to_init_py(service):
     path = os.path.join(os.path.dirname(__file__), "..", "moto", "__init__.py")
-    with open(path) as f:
-        lines = [_.replace("\n", "") for _ in f.readlines()]
+    with open(path) as fhandle:
+        lines = [_.replace("\n", "") for _ in fhandle.readlines()]
 
     if any(_ for _ in lines if re.match("^mock_{}.*lazy_load(.*)$".format(service), _)):
         return
@@ -130,20 +136,16 @@ def append_mock_to_init_py(service):
     lines.insert(last_import_line_index + 1, new_line)
 
     body = "\n".join(lines) + "\n"
-    with open(path, "w") as f:
-        f.write(body)
+    with open(path, "w") as fhandle:
+        fhandle.write(body)
 
 
 def append_mock_dict_to_backends_py(service):
     path = os.path.join(os.path.dirname(__file__), "..", "moto", "backends.py")
-    with open(path) as f:
-        lines = [_.replace("\n", "") for _ in f.readlines()]
+    with open(path) as fhandle:
+        lines = [_.replace("\n", "") for _ in fhandle.readlines()]
 
-    if any(
-        _
-        for _ in lines
-        if re.match('.*"{}": {}_backends.*'.format(service, service), _)
-    ):
+    if any(_ for _ in lines if re.match(f'.*"{service}": {service}_backends.*', _)):
         return
     filtered_lines = [_ for _ in lines if re.match('.*".*":.*_backends.*', _)]
     last_elem_line_index = lines.index(filtered_lines[-1])
@@ -157,11 +159,11 @@ def append_mock_dict_to_backends_py(service):
     lines.insert(last_elem_line_index + 1, new_line)
 
     body = "\n".join(lines) + "\n"
-    with open(path, "w") as f:
-        f.write(body)
+    with open(path, "w") as fhandle:
+        fhandle.write(body)
 
 
-def initialize_service(service, operation, api_protocol):
+def initialize_service(service, api_protocol):
     """create lib and test dirs if not exist"""
     lib_dir = get_lib_dir(service)
     test_dir = get_test_dir(service)
@@ -211,18 +213,18 @@ def initialize_service(service, operation, api_protocol):
     append_mock_dict_to_backends_py(service)
 
 
-def to_upper_camel_case(s):
-    return "".join([_.title() for _ in s.split("_")])
+def to_upper_camel_case(string):
+    return "".join([_.title() for _ in string.split("_")])
 
 
-def to_lower_camel_case(s):
-    words = s.split("_")
+def to_lower_camel_case(string):
+    words = string.split("_")
     return "".join(words[:1] + [_.title() for _ in words[1:]])
 
 
-def to_snake_case(s):
-    s1 = re.sub("(.)([A-Z][a-z]+)", r"\1_\2", s)
-    return re.sub("([a-z0-9])([A-Z])", r"\1_\2", s1).lower()
+def to_snake_case(string):
+    new_string = re.sub("(.)([A-Z][a-z]+)", r"\1_\2", string)
+    return re.sub("([a-z0-9])([A-Z])", r"\1_\2", new_string).lower()
 
 
 def get_operation_name_in_keys(operation_name, operation_keys):
@@ -274,7 +276,7 @@ def get_function_in_responses(service, operation, protocol):
             get_escaped_service(service), operation
         )
     for input_name in input_names:
-        body += "        {}={},\n".format(input_name, input_name)
+        body += f"        {input_name}={input_name},\n"
 
     body += "    )\n"
     if protocol == "query":
@@ -282,7 +284,7 @@ def get_function_in_responses(service, operation, protocol):
             operation.upper()
         )
         body += "    return template.render({})\n".format(
-            ", ".join(["{}={}".format(_, _) for _ in output_names])
+            ", ".join([f"{n}={n}" for n in output_names])
         )
     elif protocol in ["json", "rest-json"]:
         body += "    # TODO: adjust response\n"
@@ -324,20 +326,24 @@ def get_function_in_models(service, operation):
     return body
 
 
-def _get_subtree(name, shape, replace_list, name_prefix=[]):
+def _get_subtree(name, shape, replace_list, name_prefix=None):
+    if not name_prefix:
+        name_prefix = []
+
     class_name = shape.__class__.__name__
     if class_name in ("StringShape", "Shape"):
-        t = etree.Element(name)
+        tree = etree.Element(name)
         if name_prefix:
-            t.text = "{{ %s.%s }}" % (name_prefix[-1], to_snake_case(name))
+            tree.text = "{{ %s.%s }}" % (name_prefix[-1], to_snake_case(name))
         else:
-            t.text = "{{ %s }}" % to_snake_case(name)
-        return t
-    elif class_name in ("ListShape",):
+            tree.text = "{{ %s }}" % to_snake_case(name)
+        return tree
+
+    if class_name in ("ListShape",):
         replace_list.append((name, name_prefix))
-        t = etree.Element(name)
+        tree = etree.Element(name)
         t_member = etree.Element("member")
-        t.append(t_member)
+        tree.append(t_member)
         for nested_name, nested_shape in shape.member.members.items():
             t_member.append(
                 _get_subtree(
@@ -347,7 +353,7 @@ def _get_subtree(name, shape, replace_list, name_prefix=[]):
                     name_prefix + [singularize(name.lower())],
                 )
             )
-        return t
+        return tree
     raise ValueError("Not supported Shape")
 
 
@@ -417,8 +423,8 @@ def get_response_query_template(service, operation):
 
 
 def insert_code_to_class(path, base_class, new_code):
-    with open(path) as f:
-        lines = [_.replace("\n", "") for _ in f.readlines()]
+    with open(path) as fhandle:
+        lines = [_.replace("\n", "") for _ in fhandle.readlines()]
     mod_path = os.path.splitext(path)[0].replace("/", ".")
     mod = importlib.import_module(mod_path)
     clsmembers = inspect.getmembers(mod, inspect.isclass)
@@ -436,8 +442,8 @@ def insert_code_to_class(path, base_class, new_code):
     lines = lines[:end_line_no] + func_lines + lines[end_line_no:]
 
     body = "\n".join(lines) + "\n"
-    with open(path, "w") as f:
-        f.write(body)
+    with open(path, "w") as fhandle:
+        fhandle.write(body)
 
 
 def insert_url(service, operation, api_protocol):
@@ -452,8 +458,8 @@ def insert_url(service, operation, api_protocol):
     path = os.path.join(
         os.path.dirname(__file__), "..", "moto", get_escaped_service(service), "urls.py"
     )
-    with open(path) as f:
-        lines = [_.replace("\n", "") for _ in f.readlines()]
+    with open(path) as fhandle:
+        lines = [_.replace("\n", "") for _ in fhandle.readlines()]
 
     if any(_ for _ in lines if re.match(uri, _)):
         return
@@ -480,8 +486,8 @@ def insert_url(service, operation, api_protocol):
     lines.insert(last_elem_line_index + 1, new_line)
 
     body = "\n".join(lines) + "\n"
-    with open(path, "w") as f:
-        f.write(body)
+    with open(path, "w") as fhandle:
+        fhandle.write(body)
 
 
 def insert_codes(service, operation, api_protocol):
@@ -495,11 +501,11 @@ def insert_codes(service, operation, api_protocol):
     # insert template
     if api_protocol == "query":
         template = get_response_query_template(service, operation)
-        with open(responses_path) as f:
-            lines = [_[:-1] for _ in f.readlines()]
+        with open(responses_path) as fhandle:
+            lines = [_[:-1] for _ in fhandle.readlines()]
         lines += template.splitlines()
-        with open(responses_path, "w") as f:
-            f.write("\n".join(lines))
+        with open(responses_path, "w") as fhandle:
+            fhandle.write("\n".join(lines))
 
     # edit models.py
     models_path = "moto/{}/models.py".format(get_escaped_service(service))
@@ -514,7 +520,7 @@ def insert_codes(service, operation, api_protocol):
 def main():
     service, operation = select_service_and_operation()
     api_protocol = boto3.client(service)._service_model.metadata["protocol"]
-    initialize_service(service, operation, api_protocol)
+    initialize_service(service, api_protocol)
 
     if api_protocol in ["query", "json", "rest-json"]:
         insert_codes(service, operation, api_protocol)
@@ -525,7 +531,10 @@ def main():
             "yellow",
         )
 
-    click.echo('You will still need to add the mock into "__init__.py"'.format(service))
+    click.echo(
+        'You will still need to add the mock into "docs/index.rst" and '
+        '"IMPLEMENTATION_COVERAGE.md"'
+    )
 
 
 if __name__ == "__main__":

scripts/template/lib/__init__.py.j2

@@ -1,7 +1,5 @@
-from __future__ import unicode_literals
+"""{{ escaped_service }} module initialization; sets value for base decorator."""
 from .models import {{ escaped_service }}_backends
 from ..core.models import base_decorator
 
-{{ escaped_service }}_backend = {{ escaped_service }}_backends['us-east-1']
 mock_{{ escaped_service }} = base_decorator({{ escaped_service }}_backends)
-

scripts/template/lib/exceptions.py.j2

@@ -1,4 +1,4 @@
-from __future__ import unicode_literals
-from moto.core.exceptions import RESTError
+"""Exceptions raised by the {{ escaped_service }} service."""
+from moto.core.exceptions import JsonRESTError
 
 

scripts/template/lib/models.py.j2

@@ -1,14 +1,18 @@
-from __future__ import unicode_literals
+"""{{ service_class }}Backend class with methods for supported APIs."""
 from boto3 import Session
+
 from moto.core import BaseBackend, BaseModel
 
 
 class {{ service_class }}Backend(BaseBackend):
+
+    """Implementation of {{ service_class }} APIs."""
+
     def __init__(self, region_name=None):
-        super({{ service_class }}Backend, self).__init__()
         self.region_name = region_name
 
     def reset(self):
+        """Re-initialize all attributes for this instance."""
         region_name = self.region_name
         self.__dict__ = {}
         self.__init__(region_name)
@@ -17,9 +21,13 @@ class {{ service_class }}Backend(BaseBackend):
 
 
 {{ escaped_service }}_backends = {}
-for region in Session().get_available_regions("{{ service }}"):
-    {{ escaped_service }}_backends[region] = {{ service_class }}Backend()
-for region in Session().get_available_regions("{{ service }}", partition_name="aws-us-gov"):
-    {{ escaped_service }}_backends[region] = {{ service_class }}Backend()
-for region in Session().get_available_regions("{{ service }}", partition_name="aws-cn"):
-    {{ escaped_service }}_backends[region] = {{ service_class }}Backend()
+for available_region in Session().get_available_regions("{{ service }}"):
+    {{ escaped_service }}_backends[available_region] = {{ service_class }}Backend()
+for available_region in Session().get_available_regions(
+    "{{ service }}", partition_name="aws-us-gov"
+):
+    {{ escaped_service }}_backends[available_region] = {{ service_class }}Backend()
+for available_region in Session().get_available_regions(
+    "{{ service }}", partition_name="aws-cn"
+):
+    {{ escaped_service }}_backends[available_region] = {{ service_class }}Backend()

scripts/template/lib/responses.py.j2

@@ -1,13 +1,17 @@
-from __future__ import unicode_literals
+"""Handles incoming {{ escaped_service }} requests, invokes methods, returns responses."""
+import json
+
 from moto.core.responses import BaseResponse
 from .models import {{ escaped_service }}_backends
-import json
 
 
 class {{ service_class }}Response(BaseResponse):
-    SERVICE_NAME = '{{ service }}'
+
+    """Handler for {{ service_class }} requests and responses."""
+
     @property
     def {{ escaped_service }}_backend(self):
+        """Return backend instance specific for this region."""
         return {{ escaped_service }}_backends[self.region]
 
     # add methods from here

scripts/template/lib/urls.py.j2

@@ -1,4 +1,4 @@
-from __future__ import unicode_literals
+"""{{ escaped_service }} base URL and path."""
 from .responses import {{ service_class }}Response
 
 url_bases = [

scripts/template/test/test_server.py.j2

@@ -1,13 +1,9 @@
-from __future__ import unicode_literals
-
+"""Test different server responses."""
 import sure  # noqa
 
 import moto.server as server
 from moto import mock_{{ escaped_service }}
 
-'''
-Test the different server responses
-'''
 
 @mock_{{ escaped_service }}
 def test_{{ escaped_service }}_list():

scripts/template/test/test_service.py.j2

@@ -1,11 +1,12 @@
-from __future__ import unicode_literals
-
+"""Unit tests for {{ escaped_service }}-supported APIs."""
 import boto3
+
 import sure  # noqa
 from moto import mock_{{ escaped_service }}
 
 
 @mock_{{ escaped_service }}
 def test_list():
+    """Test input/output of the list API."""
     # do test
     pass