Add flag --check in setup.py black command

Author: mateuszmidor

.github/workflows/kentik-api.yml

@@ -49,7 +49,7 @@ jobs:
           python -m pip install --upgrade -r requirements-dev.txt
       - name: Black
         working-directory: ./kentik_api_library
-        run: python3 setup.py black
+        run: python3 setup.py black --check
       - name: Mypy
         working-directory: ./kentik_api_library
         run: python3 setup.py mypy

kentik_api_library/pyproject.toml

@@ -5,8 +5,6 @@ build-backend = "setuptools.build_meta"
 [tool.black]
 line-length = 120
 target-version = ['py39']
-check = true
-fast = true
 
 [tool.isort]
 line_length = 120

kentik_api_library/setup.py

@@ -83,18 +83,25 @@ def run(self):
 class Black(Command):
     """Custom command to run black"""
 
-    description = "run black on all relevant code; read configuration from pyproject.toml"
-    user_options = []
+    description = "run black on all relevant code"
+    user_options = [("dirs=", None, "Directories to check with black"), ("check", None, "Run in check mode")]
 
     def initialize_options(self) -> None:
-        pass
+        self.dirs = ["."]
+        self.check = False
 
     def finalize_options(self):
-        pass
+        """Post-process options."""
+        for d in self.dirs:
+            assert os.path.exists(d), "Path {} does not exist.".format(d)
 
     def run(self):
         """Run command"""
-        cmd = ["black", "."]
+        cmd = ["black"]
+        if self.check:
+            cmd.append("--check")
+        for d in self.dirs:
+            cmd.append(d)
         run_cmd(cmd, self.announce)