[Python] Require black and isort for new Python files. (#8096)

* [Python] Require black and isort for new Python files.

- Require black and isort for spark and dask module.

These files are relatively new and are more conform to the black formatter. We will
convert the rest of the library as we move forward.

Other libraries including dask/distributed and optuna use the same formatting style and
have a more strict standard. The black formatter is indeed quite nice, automating it can
help us unify the code style.

- Gather Python checks into a single script.

.github/workflows/main.yml

@@ -146,24 +146,6 @@ jobs:
       run: |
         make lint
 
-  mypy:
-    runs-on: ubuntu-latest
-    name: Type checking for Python
-    steps:
-    - uses: actions/checkout@v2
-      with:
-        submodules: 'true'
-    - uses: actions/setup-python@v2
-      with:
-        python-version: "3.8"
-        architecture: 'x64'
-    - name: Install Python packages
-      run: |
-        python -m pip install wheel setuptools mypy pandas dask[complete] distributed
-    - name: Run mypy
-      run: |
-        make mypy
-
   doxygen:
     runs-on: ubuntu-latest
     name: Generate C/C++ API doc using Doxygen

.github/workflows/python_tests.yml

@@ -3,6 +3,37 @@ name: XGBoost-Python-Tests
 on: [push, pull_request]
 
 jobs:
+  python-mypy-lint:
+    runs-on: ubuntu-latest
+    name: Type and format checks for the Python package
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+        python-version: ["3.8"]
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        submodules: 'true'
+    - uses: conda-incubator/setup-miniconda@v2
+      with:
+        auto-update-conda: true
+        python-version: ${{ matrix.python-version }}
+        activate-environment: python_lint
+        environment-file: tests/ci_build/conda_env/python_lint.yml
+    - name: Display Conda env
+      shell: bash -l {0}
+      run: |
+        conda info
+        conda list
+    - name: Run mypy
+      shell: bash -l {0}
+      run: |
+        python tests/ci_build/lint_python.py --format=0 --type-check=1
+    - name: Run formatter
+      shell: bash -l {0}
+      run: |
+        python tests/ci_build/lint_python.py --format=1 --type-check=0
+
   python-sdist-test:
     runs-on: ${{ matrix.os }}
     name: Test installing XGBoost Python source package on ${{ matrix.os }}

Makefile

@@ -87,19 +87,6 @@ cover: check
 endif
 
 
-# dask is required to pass, others are not
-# If any of the dask tests failed, contributor won't see the other error.
-mypy:
-	cd python-package; \
-	mypy . && \
-	mypy ../demo/guide-python/external_memory.py && \
-	mypy ../demo/guide-python/categorical.py && \
-	mypy ../demo/guide-python/cat_in_the_dat.py && \
-	mypy ../tests/python-gpu/test_gpu_with_dask.py && \
-	mypy ../tests/python/test_data_iterator.py && \
-	mypy ../tests/python-gpu/test_gpu_data_iterator.py  || exit 1; \
-	mypy . || true ;
-
 clean:
 	$(RM) -rf build lib bin *~ */*~ */*/*~ */*/*/*~ */*.o */*/*.o */*/*/*.o #xgboost
 	$(RM) -rf build_tests *.gcov tests/cpp/xgboost_test

python-package/xgboost/dask.py

@@ -31,49 +31,76 @@ Optional dask configuration
       dask.config.set({"xgboost.scheduler_address": "192.0.0.100:12345"})
 
 """
-import platform
-import logging
 import collections
+import logging
+import platform
 import socket
-from contextlib import contextmanager
 from collections import defaultdict
-from threading import Thread
+from contextlib import contextmanager
 from functools import partial, update_wrapper
-from typing import TYPE_CHECKING, List, Tuple, Callable, Optional, Any, Union, Dict, Set
-from typing import Sequence
-from typing import Awaitable, Generator, TypeVar
+from threading import Thread
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Awaitable,
+    Callable,
+    Dict,
+    Generator,
+    List,
+    Optional,
+    Sequence,
+    Set,
+    Tuple,
+    TypeVar,
+    Union,
+)
 
 import numpy
 
-from . import rabit, config
-
-from .callback import TrainingCallback
-
-from .compat import LazyLoader
-from .compat import scipy_sparse
-from .compat import PANDAS_INSTALLED, DataFrame, Series, pandas_concat
-from .compat import lazy_isinstance
-
+from . import config, rabit
 from ._typing import FeatureNames, FeatureTypes
-
-from .core import DMatrix, DeviceQuantileDMatrix, Booster, _expect, DataIter
-from .core import Objective, Metric
-from .core import _deprecate_positional_args, _has_categorical
-from .training import train as worker_train
+from .callback import TrainingCallback
+from .compat import (
+    PANDAS_INSTALLED,
+    DataFrame,
+    LazyLoader,
+    Series,
+    lazy_isinstance,
+    pandas_concat,
+    scipy_sparse,
+)
+from .core import (
+    Booster,
+    DataIter,
+    DeviceQuantileDMatrix,
+    DMatrix,
+    Metric,
+    Objective,
+    _deprecate_positional_args,
+    _expect,
+    _has_categorical,
+)
+from .sklearn import (
+    XGBClassifier,
+    XGBClassifierBase,
+    XGBModel,
+    XGBRanker,
+    XGBRankerMixIn,
+    XGBRegressorBase,
+    _check_rf_callback,
+    _cls_predict_proba,
+    _objective_decorator,
+    _wrap_evaluation_matrices,
+    xgboost_model_doc,
+)
 from .tracker import RabitTracker, get_host_ip
-from .sklearn import XGBModel, XGBClassifier, XGBRegressorBase, XGBClassifierBase
-from .sklearn import _wrap_evaluation_matrices, _objective_decorator, _check_rf_callback
-from .sklearn import XGBRankerMixIn
-from .sklearn import xgboost_model_doc
-from .sklearn import _cls_predict_proba
-from .sklearn import XGBRanker
-
+from .training import train as worker_train
 
 if TYPE_CHECKING:
-    from dask import dataframe as dd
-    from dask import array as da
     import dask
     import distributed
+    from dask import array as da
+    from dask import dataframe as dd
 else:
     dd = LazyLoader("dd", globals(), "dask.dataframe")
     da = LazyLoader("da", globals(), "dask.array")

python-package/xgboost/spark/core.py

@@ -4,23 +4,21 @@
 # pylint: disable=too-few-public-methods
 import numpy as np
 import pandas as pd
-from scipy.special import expit, softmax  # pylint: disable=no-name-in-module
-
-from pyspark.ml.functions import array_to_vector, vector_to_array
 from pyspark.ml import Estimator, Model
+from pyspark.ml.functions import array_to_vector, vector_to_array
 from pyspark.ml.linalg import VectorUDT
+from pyspark.ml.param import Param, Params, TypeConverters
 from pyspark.ml.param.shared import (
     HasFeaturesCol,
     HasLabelCol,
-    HasWeightCol,
     HasPredictionCol,
     HasProbabilityCol,
     HasRawPredictionCol,
     HasValidationIndicatorCol,
+    HasWeightCol,
 )
-from pyspark.ml.param import Param, Params, TypeConverters
 from pyspark.ml.util import MLReadable, MLWritable
-from pyspark.sql.functions import col, pandas_udf, countDistinct, struct
+from pyspark.sql.functions import col, countDistinct, pandas_udf, struct
 from pyspark.sql.types import (
     ArrayType,
     DoubleType,
@@ -29,35 +27,32 @@ from pyspark.sql.types import (
     LongType,
     ShortType,
 )
-
-import xgboost
-from xgboost import XGBClassifier, XGBRegressor
+from scipy.special import expit, softmax  # pylint: disable=no-name-in-module
 from xgboost.core import Booster
 from xgboost.training import train as worker_train
 
-from .data import (
-    _convert_partition_data_to_dmatrix,
-)
+import xgboost
+from xgboost import XGBClassifier, XGBRegressor
+
+from .data import _convert_partition_data_to_dmatrix
 from .model import (
-    SparkXGBReader,
-    SparkXGBWriter,
     SparkXGBModelReader,
     SparkXGBModelWriter,
+    SparkXGBReader,
+    SparkXGBWriter,
 )
+from .params import HasArbitraryParamsDict, HasBaseMarginCol
 from .utils import (
-    get_logger, _get_max_num_concurrent_tasks,
-    _get_default_params_from_func,
-    get_class_name,
     RabitContext,
-    _get_rabit_args,
     _get_args_from_message_list,
+    _get_default_params_from_func,
+    _get_gpu_id,
+    _get_max_num_concurrent_tasks,
+    _get_rabit_args,
     _get_spark_session,
     _is_local,
-    _get_gpu_id,
-)
-from .params import (
-    HasArbitraryParamsDict,
-    HasBaseMarginCol,
+    get_class_name,
+    get_logger,
 )
 
 # Put pyspark specific params here, they won't be passed to XGBoost.
@@ -282,10 +277,7 @@ class _SparkXGBParams(
                 .get("spark.task.resource.gpu.amount")
             )
 
-            is_local = _is_local(
-                _get_spark_session()
-                .sparkContext
-            )
+            is_local = _is_local(_get_spark_session().sparkContext)
 
             if is_local:
                 # checking spark local mode.
@@ -301,7 +293,8 @@ class _SparkXGBParams(
                 # gpu numbers and raising the exception.
                 get_logger(self.__class__.__name__).warning(
                     "You enabled use_gpu in spark local mode. Please make sure your local node "
-                    "has at least %d GPUs", self.getOrDefault(self.num_workers)
+                    "has at least %d GPUs",
+                    self.getOrDefault(self.num_workers),
                 )
             else:
                 # checking spark non-local mode.
@@ -316,7 +309,7 @@ class _SparkXGBParams(
                     get_logger(self.__class__.__name__).warning(
                         "You configured %s GPU cores for each spark task, but in "
                         "XGBoost training, every Spark task will only use one GPU core.",
-                        gpu_per_task
+                        gpu_per_task,
                     )
 
 
@@ -545,7 +538,7 @@ class _SparkXGBEstimator(Estimator, _SparkXGBParams, MLReadable, MLWritable):
                 "training is greater than current max number of concurrent "
                 "spark task slots, you need wait until more task slots available "
                 "or you need increase spark cluster workers.",
-                num_workers
+                num_workers,
             )
 
         if self._repartition_needed(dataset):
@@ -568,10 +561,7 @@ class _SparkXGBEstimator(Estimator, _SparkXGBParams, MLReadable, MLWritable):
         booster_params["nthread"] = cpu_per_task
         use_gpu = self.getOrDefault(self.use_gpu)
 
-        is_local = _is_local(
-            _get_spark_session()
-            .sparkContext
-        )
+        is_local = _is_local(_get_spark_session().sparkContext)
 
         def _train_booster(pandas_df_iter):
             """
@@ -584,8 +574,9 @@ class _SparkXGBEstimator(Estimator, _SparkXGBParams, MLReadable, MLWritable):
             context.barrier()
 
             if use_gpu:
-                booster_params["gpu_id"] = context.partitionId() if is_local \
-                    else _get_gpu_id(context)
+                booster_params["gpu_id"] = (
+                    context.partitionId() if is_local else _get_gpu_id(context)
+                )
 
             _rabit_args = ""
             if context.partitionId() == 0:

python-package/xgboost/spark/data.py

@@ -2,8 +2,10 @@
 """Xgboost pyspark integration submodule for data related functions."""
 # pylint: disable=too-many-arguments
 from typing import Iterator
+
 import numpy as np
 import pandas as pd
+
 from xgboost import DMatrix
 
 

python-package/xgboost/spark/estimator.py

@@ -2,12 +2,14 @@
 """Xgboost pyspark integration submodule for estimator API."""
 # pylint: disable=too-many-ancestors
 from pyspark.ml.param.shared import HasProbabilityCol, HasRawPredictionCol
+
 from xgboost import XGBClassifier, XGBRegressor
+
 from .core import (
-    _SparkXGBEstimator,
     SparkXGBClassifierModel,
     SparkXGBRegressorModel,
     _set_pyspark_xgb_cls_param_attrs,
+    _SparkXGBEstimator,
 )
 
 

python-package/xgboost/spark/model.py

@@ -5,13 +5,12 @@ import base64
 import os
 import uuid
 
-from pyspark import cloudpickle
-from pyspark import SparkFiles
-from pyspark.sql import SparkSession
+from pyspark import SparkFiles, cloudpickle
 from pyspark.ml.util import DefaultParamsReader, DefaultParamsWriter, MLReader, MLWriter
+from pyspark.sql import SparkSession
 from xgboost.core import Booster
 
-from .utils import get_logger, get_class_name
+from .utils import get_class_name, get_logger
 
 
 def _get_or_create_tmp_dir():
@@ -250,7 +249,9 @@ class SparkXGBModelReader(MLReader):
             self.cls, path, self.sc, self.logger
         )
 
-        xgb_sklearn_params = py_model._gen_xgb_params_dict(gen_xgb_sklearn_estimator_param=True)
+        xgb_sklearn_params = py_model._gen_xgb_params_dict(
+            gen_xgb_sklearn_estimator_param=True
+        )
         model_load_path = os.path.join(path, "model.json")
 
         ser_xgb_model = (
@@ -263,8 +264,6 @@ class SparkXGBModelReader(MLReader):
         def create_xgb_model():
             return self.cls._xgb_cls()(**xgb_sklearn_params)
 
-        xgb_model = deserialize_xgb_model(
-            ser_xgb_model, create_xgb_model
-        )
+        xgb_model = deserialize_xgb_model(ser_xgb_model, create_xgb_model)
         py_model._xgb_sklearn_model = xgb_model
         return py_model

python-package/xgboost/spark/utils.py

@@ -1,15 +1,15 @@
 # type: ignore
 """Xgboost pyspark integration submodule for helper functions."""
 import inspect
-from threading import Thread
-import sys
 import logging
+import sys
+from threading import Thread
 
 import pyspark
 from pyspark.sql.session import SparkSession
+from xgboost.tracker import RabitTracker
 
 from xgboost import rabit
-from xgboost.tracker import RabitTracker
 
 
 def get_class_name(cls):
@@ -140,13 +140,11 @@ def _get_gpu_id(task_context) -> int:
     """Get the gpu id from the task resources"""
     if task_context is None:
         # This is a safety check.
-        raise RuntimeError(
-            "_get_gpu_id should not be invoked from driver side."
-        )
+        raise RuntimeError("_get_gpu_id should not be invoked from driver side.")
     resources = task_context.resources()
-    if 'gpu' not in resources:
+    if "gpu" not in resources:
         raise RuntimeError(
             "Couldn't get the gpu id, Please check the GPU resource configuration"
         )
     # return the first gpu id.
-    return int(resources['gpu'].addresses[0].strip())
+    return int(resources["gpu"].addresses[0].strip())

tests/ci_build/conda_env/python_lint.yml

@@ -0,0 +1,15 @@
+name: python_lint
+channels:
+- conda-forge
+dependencies:
+- python=3.8
+- wheel
+- setuptools
+- mypy
+- numpy
+- scipy
+- pandas
+- dask
+- distributed
+- black
+- isort

tests/ci_build/lint_python.py

@@ -0,0 +1,63 @@
+import argparse
+import os
+import subprocess
+import sys
+
+from test_utils import DirectoryExcursion
+
+CURDIR = os.path.normpath(os.path.abspath(os.path.dirname(__file__)))
+PROJECT_ROOT = os.path.normpath(os.path.join(CURDIR, os.path.pardir, os.path.pardir))
+
+
+def run_formatter(rel_path: str):
+    path = os.path.join(PROJECT_ROOT, rel_path)
+    isort_ret = subprocess.run(["isort", "--check", "--profile=black", path]).returncode
+    black_ret = subprocess.run(
+        ["black", "--check", "./python-package/xgboost/dask.py"]
+    ).returncode
+    if isort_ret != 0 or black_ret != 0:
+        msg = (
+            "Please run the following command on your machine to address the format"
+            f" errors:\n isort --check --profile=black {rel_path}\n black {rel_path}\n"
+        )
+        print(msg, file=sys.stdout)
+        return False
+    return True
+
+
+def run_mypy(rel_path: str):
+    with DirectoryExcursion(os.path.join(PROJECT_ROOT, "python-package")):
+        path = os.path.join(PROJECT_ROOT, rel_path)
+        ret = subprocess.run(["mypy", path])
+        if ret.returncode != 0:
+            return False
+        return True
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--format", type=int, choices=[0, 1], default=1)
+    parser.add_argument("--type-check", type=int, choices=[0, 1], default=1)
+    args = parser.parse_args()
+    if args.format == 1:
+        if not all(
+            [
+                run_formatter("python-package/xgboost/dask.py"),
+                run_formatter("python-package/xgboost/spark"),
+            ]
+        ):
+            sys.exit(-1)
+
+    if args.type_check == 1:
+        if not all(
+            run_mypy(path)
+            for path in [
+                "python-package/xgboost/",
+                "demo/guide-python/external_memory.py",
+                "demo/guide-python/cat_in_the_dat.py",
+                "tests/python/test_data_iterator.py",
+                "tests/python-gpu/test_gpu_with_dask.py",
+                "tests/python-gpu/test_gpu_data_iterator.py",
+            ]
+        ):
+            sys.exit(-1)

tests/ci_build/test_r_package.py

@@ -1,6 +1,7 @@
 import argparse
 import os
 import subprocess
+from test_utils import DirectoryExcursion
 
 ROOT = os.path.normpath(
     os.path.join(os.path.dirname(os.path.abspath(__file__)), os.path.pardir,
@@ -8,18 +9,6 @@ ROOT = os.path.normpath(
 r_package = os.path.join(ROOT, 'R-package')
 
 
-class DirectoryExcursion:
-    def __init__(self, path: os.PathLike):
-        self.path = path
-        self.curdir = os.path.normpath(os.path.abspath(os.path.curdir))
-
-    def __enter__(self):
-        os.chdir(self.path)
-
-    def __exit__(self, *args):
-        os.chdir(self.curdir)
-
-
 def get_mingw_bin():
     return os.path.join('c:/rtools40/mingw64/', 'bin')
 

tests/ci_build/test_utils.py

@@ -0,0 +1,14 @@
+import os
+from typing import Union
+
+
+class DirectoryExcursion:
+    def __init__(self, path: Union[os.PathLike, str]):
+        self.path = path
+        self.curdir = os.path.normpath(os.path.abspath(os.path.curdir))
+
+    def __enter__(self):
+        os.chdir(self.path)
+
+    def __exit__(self, *args):
+        os.chdir(self.curdir)