Update format strings to f strings

Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.7-slim-buster
+FROM python:3.8-slim-buster
 
 RUN pip install \
     cookiecutter==1.6.0

cookiecutter-docker.sh

@@ -62,5 +62,3 @@ run_cookiecutter() {
 
 process_args "$@"
 run_cookiecutter
-
-exit 0

cookiecutter.json

@@ -6,7 +6,7 @@
   "app_name": "{{cookiecutter.project_name.lower().replace('-', '_').replace(' ', '_')}}",
   "project_short_description": "A flasky app.",
   "use_pipenv": ["no", "yes"],
-	"python_version": ["3.7", "3.6"],
-	"node_version": ["12", "10", "8"],
+  "python_version": ["3.8", "3.7", "3.6"],
+  "node_version": ["12", "10"],
   "use_heroku": ["no", "yes"]
 }

hooks/pre_gen_project.py

@@ -31,7 +31,7 @@ def validate_python_module_name():
     module_name = "{{ cookiecutter.app_name }}"
     if not re.match(MODULE_REGEX, module_name):
         log_warning(module_name)
-        raise ValueError
+        sys.exit(1)
 
 
 if __name__ == "__main__":

{{cookiecutter.app_name}}/tests/factories.py

@@ -20,8 +20,8 @@ class BaseFactory(SQLAlchemyModelFactory):
 class UserFactory(BaseFactory):
     """User factory."""
 
-    username = Sequence(lambda n: "user{0}".format(n))
-    email = Sequence(lambda n: "user{0}@example.com".format(n))
+    username = Sequence(lambda n: f"user{n}")
+    email = Sequence(lambda n: f"user{n}@example.com")
     password = PostGenerationMethodCall("set_password", "example")
     active = True
 

{{cookiecutter.app_name}}/{{cookiecutter.app_name}}/app.py

@@ -61,7 +61,7 @@ def register_errorhandlers(app):
         """Render error template."""
         # If a HTTPException, pull the `code` attribute; default to 500
         error_code = getattr(error, "code", 500)
-        return render_template("{0}.html".format(error_code)), error_code
+        return render_template(f"{error_code}.html"), error_code
 
     for errcode in [401, 404, 500]:
         app.errorhandler(errcode)(render_error)

{{cookiecutter.app_name}}/{{cookiecutter.app_name}}/commands.py

@@ -49,7 +49,7 @@ def lint(fix_imports, check):
     def execute_tool(description, *args):
         """Execute a checking tool with its arguments."""
         command_line = list(args) + files_and_directories
-        click.echo("{}: {}".format(description, " ".join(command_line)))
+        click.echo(f"{description}: {' '.join(command_line)}")
         rv = call(command_line)
         if rv != 0:
             exit(rv)

{{cookiecutter.app_name}}/{{cookiecutter.app_name}}/database.py

@@ -78,7 +78,7 @@ def reference_col(
     column_kwargs = column_kwargs or {}
 
     return Column(
-        db.ForeignKey("{0}.{1}".format(tablename, pk_name), **foreign_key_kwargs),
+        db.ForeignKey(f"{tablename}.{pk_name}", **foreign_key_kwargs),
         nullable=nullable,
-        **column_kwargs
+        **column_kwargs,
     )

{{cookiecutter.app_name}}/{{cookiecutter.app_name}}/user/models.py

@@ -29,7 +29,7 @@ class Role(SurrogatePK, Model):
 
     def __repr__(self):
         """Represent instance as a unique string."""
-        return "<Role({name})>".format(name=self.name)
+        return f"<Role({self.name})>"
 
 
 class User(UserMixin, SurrogatePK, Model):
@@ -65,8 +65,8 @@ class User(UserMixin, SurrogatePK, Model):
     @property
     def full_name(self):
         """Full user name."""
-        return "{0} {1}".format(self.first_name, self.last_name)
+        return f"{self.first_name} {self.last_name}"
 
     def __repr__(self):
         """Represent instance as a unique string."""
-        return "<User({username!r})>".format(username=self.username)
+        return f"<User({self.username!r})>"

{{cookiecutter.app_name}}/{{cookiecutter.app_name}}/utils.py

@@ -7,4 +7,4 @@ def flash_errors(form, category="warning"):
     """Flash all errors for a form."""
     for field, errors in form.errors.items():
         for error in errors:
-            flash("{0} - {1}".format(getattr(form, field).label.text, error), category)
+            flash(f"{getattr(form, field).label.text} - {error}", category)