Pre commit Hooks (black, flake8, mypy, etc) [CT-105] (dbt-labs#4639)

Added pre-commit and configured hooks (black, flake8, mypy, white space formatters)
Removed code checks from tox
updated CI

Author: iknox-fa

.flake8

@@ -0,0 +1,12 @@
+[flake8]
+select =
+    E
+    W
+    F
+ignore =
+    W503 # makes Flake8 work like black
+    W504
+    E203 # makes Flake8 work like black
+    E741
+max-line-length = 99
+exclude = test

.github/workflows/main.yml

@@ -37,19 +37,10 @@ defaults:
 
 jobs:
   code-quality:
-    name: ${{ matrix.toxenv }}
+    name: code-quality
 
     runs-on: ubuntu-latest
 
-    strategy:
-      fail-fast: false
-      matrix:
-        toxenv: [flake8, mypy]
-
-    env:
-      TOXENV: ${{ matrix.toxenv }}
-      PYTEST_ADDOPTS: "-v --color=yes"
-
     steps:
       - name: Check out the repository
         uses: actions/checkout@v2
@@ -62,12 +53,16 @@ jobs:
       - name: Install python dependencies
         run: |
           pip install --user --upgrade pip
-          pip install tox
+          pip install pre-commit
+          pip install mypy==0.782
+          pip install -r editable-requirements.txt
           pip --version
-          tox --version
+          pre-commit --version
+          mypy --version
+          dbt --version
 
-      - name: Run tox
-        run: tox
+      - name: Run pre-commit hooks
+        run: pre-commit run --all-files --show-diff-on-failure
 
   unit:
     name: unit test / python ${{ matrix.python-version }}

.github/workflows/release.yml

@@ -142,7 +142,6 @@ jobs:
         run: |
           dbt --version
 
-
   github-release:
     name: GitHub Release
 

.gitignore

@@ -49,9 +49,8 @@ coverage.xml
 *,cover
 .hypothesis/
 test.env
+*.pytest_cache/
 
-# Mypy
-.mypy_cache/
 
 # Translations
 *.mo
@@ -66,10 +65,10 @@ docs/_build/
 # PyBuilder
 target/
 
-#Ipython Notebook
+# Ipython Notebook
 .ipynb_checkpoints
 
-#Emacs
+# Emacs
 *~
 
 # Sublime Text
@@ -78,6 +77,7 @@ target/
 # Vim
 *.sw*
 
+# Pyenv
 .python-version
 
 # Vim
@@ -90,6 +90,7 @@ venv/
 # AWS credentials
 .aws/
 
+# MacOS
 .DS_Store
 
 # vscode

.pre-commit-config.yaml

@@ -0,0 +1,66 @@
+# Configuration for pre-commit hooks (see https://pre-commit.com/).
+# Eventually the hooks described here will be run as tests before merging each PR.
+
+# TODO: remove global exclusion of tests when testing overhaul is complete
+exclude: ^test/
+
+# Force all unspecified python hooks to run python 3.8
+default_language_version:
+  python: python3.8
+
+repos:
+- repo: https://github.com/pre-commit/pre-commit-hooks
+  rev: v3.2.0
+  hooks:
+  - id: check-yaml
+    args: [--unsafe]
+  - id: check-json
+  - id: end-of-file-fixer
+  - id: trailing-whitespace
+  - id: check-case-conflict
+- repo: https://github.com/psf/black
+  rev: 21.12b0
+  hooks:
+  - id: black
+    args:
+    - "--line-length=99"
+    - "--target-version=py38"
+  - id: black
+    alias: black-check
+    stages: [manual]
+    args:
+    - "--line-length=99"
+    - "--target-version=py38"
+    - "--check"
+    - "--diff"
+- repo: https://gitlab.com/pycqa/flake8
+  rev: 4.0.1
+  hooks:
+  - id: flake8
+  - id: flake8
+    alias: flake8-check
+    stages: [manual]
+- repo: https://github.com/pre-commit/mirrors-mypy
+  rev: v0.782
+  hooks:
+  - id: mypy
+    # N.B.: Mypy is... a bit fragile.
+    #
+    # By using `language: system` we run this hook in the local
+    # environment instead of a pre-commit isolated one.  This is needed
+    # to ensure mypy correctly parses the project.
+
+    # It may cause trouble
+    # in that it adds environmental variables out of our control to the
+    # mix.  Unfortunately, there's nothing we can do about per pre-commit's
+    # author.
+    # See https://github.com/pre-commit/pre-commit/issues/730 for details.
+    args: [--show-error-codes]
+    files: ^core/dbt/
+    language: system
+  - id: mypy
+    alias: mypy-check
+    stages: [manual]
+    args: [--show-error-codes, --pretty]
+    files: ^core/dbt/
+    language: system

CONTRIBUTING.md

@@ -47,6 +47,7 @@ Here's a good workflow:
 - Outline your planned implementation. If you want help getting started, ask!
 - Follow the steps outlined below to develop locally. Once you have opened a PR, one of the `dbt-core` maintainers will work with you to review your code.
 - Add a test! Tests are crucial for both fixes and new features alike. We want to make sure that code works as intended, and that it avoids any bugs  previously encountered. Currently, the best resource for understanding `dbt-core`'s [unit](test/unit) and [integration](test/integration) tests is the tests themselves. One of the maintainers can help by pointing out relevant examples.
+- Check your formatting and linting with [Flake8](https://flake8.pycqa.org/en/latest/#), [Black](https://github.com/psf/black), and the rest of the hooks we have in our [pre-commit](https://pre-commit.com/) [config](https://github.com/dbt-labs/dbt-core/blob/75201be9db1cb2c6c01fa7e71a314f5e5beb060a/.pre-commit-config.yaml).
 
 In some cases, the right resolution to an open issue might be tangential to the `dbt-core` codebase. The right path forward might be a documentation update or a change that can be made in user-space. In other cases, the issue might describe functionality that the `dbt-core` maintainers are unwilling or unable to incorporate into the `dbt-core` codebase. When it is determined that an open issue describes functionality that will not translate to a code change in the `dbt-core` repository, the issue will be tagged with the `wontfix` label (see below) and closed.
 
@@ -106,6 +107,7 @@ A short list of tools used in `dbt-core` testing that will be helpful to your un
 - [`pytest`](https://docs.pytest.org/en/latest/) to discover/run tests
 - [`make`](https://users.cs.duke.edu/~ola/courses/programming/Makefiles/Makefiles.html) - but don't worry too much, nobody _really_ understands how make works and our Makefile is super simple
 - [`flake8`](https://flake8.pycqa.org/en/latest/) for code linting
+- [`black`](https://github.com/psf/black) for code formatting
 - [`mypy`](https://mypy.readthedocs.io/en/stable/) for static type checking
 - [Github Actions](https://github.com/features/actions)
 
@@ -190,19 +192,18 @@ make test
 # Runs postgres integration tests with py38 in "fail fast" mode.
 make integration
 ```
-> These make targets assume you have a recent version of [`tox`](https://tox.readthedocs.io/en/latest/) installed locally,
+> These make targets assume you have a local install of a recent version of [`tox`](https://tox.readthedocs.io/en/latest/) for unit/integration testing and pre-commit for code quality checks,
 > unless you use choose a Docker container to run tests. Run `make help` for more info.
 
 Check out the other targets in the Makefile to see other commonly used test
 suites.
 
+#### `pre-commit`
+[`pre-commit`](https.pre-commit.com) takes care of running all code-checks for formatting and linting. Run `make dev` to install `pre-commit` in your local environment.  Once this is done you can use any of the linter-based make targets as well as a git pre-commit hook that will ensure proper formatting and linting.
+
 #### `tox`
 
-[`tox`](https://tox.readthedocs.io/en/latest/) takes care of managing virtualenvs and install dependencies in order to run
-tests. You can also run tests in parallel, for example, you can run unit tests
-for Python 3.7, Python 3.8, Python 3.9, `flake8` checks, and `mypy` checks in
-parallel with `tox -p`. Also, you can run unit tests for specific python versions
-with `tox -e py37`. The configuration for these tests in located in `tox.ini`.
+[`tox`](https://tox.readthedocs.io/en/latest/) takes care of managing virtualenvs and install dependencies in order to run tests. You can also run tests in parallel, for example, you can run unit tests for Python 3.7, Python 3.8, and Python 3.9 checks in parallel with `tox -p`. Also, you can run unit tests for specific python versions with `tox -e py37`. The configuration for these tests in located in `tox.ini`.
 
 #### `pytest`
 

Makefile

@@ -8,27 +8,43 @@ endif
 
 .PHONY: dev
 dev: ## Installs dbt-* packages in develop mode along with development dependencies.
-	pip install -r dev-requirements.txt -r editable-requirements.txt
+	@\
+	pip install -r dev-requirements.txt -r editable-requirements.txt && \
+	pre-commit install
 
 .PHONY: mypy
-mypy: .env ## Runs mypy for static type checking.
-	$(DOCKER_CMD) tox -e mypy
+mypy: .env ## Runs mypy against staged changes for static type checking.
+	@\
+	$(DOCKER_CMD) pre-commit run --hook-stage manual mypy-check | grep -v "INFO"
 
 .PHONY: flake8
-flake8: .env ## Runs flake8 to enforce style guide.
-	$(DOCKER_CMD) tox -e flake8
+flake8: .env ## Runs flake8 against staged changes to enforce style guide.
+	@\
+	$(DOCKER_CMD) pre-commit run --hook-stage manual flake8-check | grep -v "INFO"
+
+.PHONY: black
+black: .env ## Runs black  against staged changes to enforce style guide.
+	@\
+	$(DOCKER_CMD) pre-commit run --hook-stage manual black-check -v | grep -v "INFO"
 
 .PHONY: lint
-lint: .env ## Runs all code checks in parallel.
-	$(DOCKER_CMD) tox -p -e flake8,mypy
+lint: .env ## Runs flake8 and mypy code checks against staged changes.
+	@\
+	$(DOCKER_CMD) pre-commit run flake8-check --hook-stage manual | grep -v "INFO"; \
+	$(DOCKER_CMD) pre-commit run mypy-check --hook-stage manual | grep -v "INFO"
 
 .PHONY: unit
 unit: .env ## Runs unit tests with py38.
+	@\
 	$(DOCKER_CMD) tox -e py38
 
 .PHONY: test
-test: .env ## Runs unit tests with py38 and code checks in parallel.
-	$(DOCKER_CMD) tox -p -e py38,flake8,mypy
+test: .env ## Runs unit tests with py38 and code checks against staged changes.
+	@\
+	$(DOCKER_CMD) tox -p -e py38; \
+	$(DOCKER_CMD) pre-commit run black-check --hook-stage manual | grep -v "INFO"; \
+	$(DOCKER_CMD) pre-commit run flake8-check --hook-stage manual | grep -v "INFO"; \
+	$(DOCKER_CMD) pre-commit run mypy-check --hook-stage manual | grep -v "INFO"
 
 .PHONY: integration
 integration: .env integration-postgres ## Alias for integration-postgres.
@@ -38,15 +54,18 @@ integration-fail-fast: .env integration-postgres-fail-fast ## Alias for integrat
 
 .PHONY: integration-postgres
 integration-postgres: .env ## Runs postgres integration tests with py38.
+	@\
 	$(DOCKER_CMD) tox -e py38-postgres -- -nauto
 
 .PHONY: integration-postgres-fail-fast
 integration-postgres-fail-fast: .env ## Runs postgres integration tests with py38 in "fail fast" mode.
+	@\
 	$(DOCKER_CMD) tox -e py38-postgres -- -x -nauto
 
 .PHONY: setup-db
 setup-db: ## Setup Postgres database with docker-compose for system testing.
-	docker-compose up -d database
+	@\
+	docker-compose up -d database && \
 	PGHOST=localhost PGUSER=root PGPASSWORD=password PGDATABASE=postgres bash test/setup_db.sh
 
 # This rule creates a file named .env that is used by docker-compose for passing
@@ -62,26 +81,29 @@ endif
 
 .PHONY: clean
 clean: ## Resets development environment.
-	rm -f .coverage
-	rm -rf .eggs/
-	rm -f .env
-	rm -rf .tox/
-	rm -rf build/
-	rm -rf dbt.egg-info/
-	rm -f dbt_project.yml
-	rm -rf dist/
-	rm -f htmlcov/*.{css,html,js,json,png}
-	rm -rf logs/
-	rm -rf target/
-	find . -type f -name '*.pyc' -delete
-	find . -type d -name '__pycache__' -depth -delete
+	@echo 'cleaning repo...'
+	@rm -f .coverage
+	@rm -rf .eggs/
+	@rm -f .env
+	@rm -rf .tox/
+	@rm -rf build/
+	@rm -rf dbt.egg-info/
+	@rm -f dbt_project.yml
+	@rm -rf dist/
+	@rm -f htmlcov/*.{css,html,js,json,png}
+	@rm -rf logs/
+	@rm -rf target/
+	@find . -type f -name '*.pyc' -delete
+	@find . -type d -name '__pycache__' -depth -delete
+	@echo 'done.'
+
 
 .PHONY: help
 help: ## Show this help message.
 	@echo 'usage: make [target] [USE_DOCKER=true]'
 	@echo
 	@echo 'targets:'
-	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
+	@grep -E '^[8+a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
 	@echo
 	@echo 'options:'
 	@echo 'use USE_DOCKER=true to run target in a docker container'

dev-requirements.txt

@@ -1,10 +1,12 @@
+black==21.12b0
 bumpversion
 flake8
 flaky
 freezegun==0.3.12
 ipdb
 mypy==0.782
 pip-tools
+pre-commit
 pytest
 pytest-dotenv
 pytest-logbook

tox.ini

@@ -1,25 +1,6 @@
 [tox]
 skipsdist = True
-envlist = py37,py38,py39,flake8,mypy
-
-[testenv:flake8]
-description = flake8 code checks
-basepython = python3.8
-skip_install = true
-commands = flake8 --select=E,W,F --ignore=W503,W504,E741,E203 --max-line-length 99 \
-  core/dbt \
-  plugins/postgres/dbt
-deps =
-  -rdev-requirements.txt
-
-[testenv:mypy]
-description = mypy static type checking
-basepython = python3.8
-skip_install = true
-commands = mypy --show-error-codes core/dbt
-deps =
-  -rdev-requirements.txt
-  -reditable-requirements.txt
+envlist = py37,py38,py39
 
 [testenv:{unit,py37,py38,py39,py}]
 description = unit testing