Add pre-commit linter & formatter

Reviewed By: tangbinh

Differential Revision: D38266929

fbshipit-source-id: 76643a3bdfcf26087ac7aa5f35678a598620690d

Author: Ananth Subramaniam

.flake8

@@ -0,0 +1,19 @@
+[flake8]
+# Suggested config from pytorch that we can adopt
+select = B,C,E,F,P,T4,W,B9
+max-line-length = 120
+# C408 ignored because we like the dict keyword argument syntax
+# E501 is not flexible enough, we're using B950 instead
+ignore =
+    E203,E305,E402,E501,E721,E741,F405,F821,F841,F999,W503,W504,C408,E302,W291,E303,
+    # shebang has extra meaning in fbcode lints, so I think it's not worth trying
+    # to line this up with executable bit
+    EXE001,
+optional-ascii-coding = True
+exclude =
+    ./.git,
+    ./docs
+    ./build
+    ./scripts,
+    ./venv,
+    *.pyi

.pre-commit-config.yaml

@@ -0,0 +1,38 @@
+default_language_version:
+    python: python3
+
+repos:
+-   repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.1.0
+    hooks:
+    -   id: trailing-whitespace
+    -   id: check-ast
+    -   id: check-merge-conflict
+    -   id: no-commit-to-branch
+    -   id: check-added-large-files
+        args: ['--maxkb=500']
+    -   id: end-of-file-fixer
+
+-   repo: https://github.com/Lucas-C/pre-commit-hooks
+    rev: v1.1.7
+    hooks:
+    -   id: insert-license
+        files: \.py$
+        args:
+        - --license-filepath
+        - docs/license_header.txt
+
+-   repo: https://github.com/pycqa/flake8
+    rev: 4.0.1
+    hooks:
+    -   id: flake8
+        args:
+        - --config=.flake8
+
+-   repo: https://github.com/omnilib/ufmt
+    rev: v1.3.0
+    hooks:
+    - id: ufmt
+      additional_dependencies:
+        - black == 22.3.0
+        - usort == 1.0.2