Develop allow python 3.7 (#2544)

* relax versions, add python 3.7 to CI

* add workflows

* try paramaterized circleci build, disable slow test

* fix workflow

* fix (?) pyversion

* set job name, fix pip freeze output

* test_requirements.txt

* fix install

* fix paths (again) - should use pushd popd instead

* use pushd and popd

* sort deps, restore unit test, cleanup CI

* relax versions more

* clean up versions in docs

* test older libs for 3.6, newer for 3.7

* pip: progress bar off

* fix gym-unity pip install

* try cat'ing setups for checksum

* dont use fallback (temporarily)

* dont turn off progress bar before upgrading pip

* PR feedback

* add parameter descriptions in CI config

.circleci/config.yml

-version: 2.0
+version: 2.1
+executors:
+  python361:
+    docker:
+      - image: circleci/python:3.6.1
+  python373:
+    docker:
+      - image: circleci/python:3.7.3
-  build:
-    docker:
-      - image: circleci/python:3.6.1
+  build_python:
+    parameters:
+      executor:
+        type: executor
+      pyversion:
+        type: string
+        description: python version to being used (currently only affects caching).
+      pip_constraints:
+        type: string
+        description: Constraints file that is passed to "pip install". We constraint older versions of libraries for older python runtime, in order to help ensure compatibility.
+    executor: << parameters.executor >>
+      - run:
+          # Combine all the python dependencies into one file so that we can use that for the cache checksum
+          name: Combine pip dependencies for caching
+          command: cat ml-agents/setup.py ml-agents-envs/setup.py gym-unity/setup.py test_requirements.txt << parameters.pip_constraints >> > python_deps.txt
+
-          - v1-dependencies-{{ checksum "ml-agents/setup.py" }}
+          # Parameterize the cache so that different python versions can get different versions of the packages
+          - v1-dependencies-py<< parameters.pyversion >>-{{ checksum "python_deps.txt" }}
-          - v1-dependencies-
+          - v1-dependencies-py<< parameters.pyversion >>-
 
       - run:
           name: Install Dependencies
             pip install --upgrade pip
             pip install --upgrade setuptools
-            cd ml-agents-envs && pip install -e .
-            cd ../ml-agents && pip install -e .
-            pip install pre-commit pytest-cov==2.6.1
-            cd ../gym-unity && pip install -e .
+            pip install --progress-bar=off -e ./ml-agents-envs -c << parameters.pip_constraints >>
+            pip install --progress-bar=off -e ./ml-agents -c << parameters.pip_constraints >>
+            pip install --progress-bar=off -r test_requirements.txt -c << parameters.pip_constraints >>
+            pip install --progress-bar=off -e ./gym-unity -c << parameters.pip_constraints >>
-          key: v1-dependencies-{{ checksum "ml-agents/setup.py" }}
+          key: v1-dependencies-py<< parameters.pyversion >>-{{ checksum "python_deps.txt" }}
+          # This also dumps the installed pip packages to a file, so we can see what versions are actually being used.
+            pip freeze > test-reports/pip_versions.txt
             pytest --cov=ml-agents --cov=ml-agents-envs --cov=gym-unity --cov-report html --junitxml=test-reports/junit.xml -p no:warnings
 
       - run:
       - store_artifacts:
           path: htmlcov
           destination: htmlcov
+
 
   markdown_link_check:
     docker:
             pre-commit run --hook-stage manual markdown-link-check --all-files
 
 workflows:
-  version: 2
-  build_and_test:
+  workflow:
-      - build
+      - build_python:
+          name: python_3.6.1
+          executor: python361
+          pyversion: 3.6.1
+          # Test python 3.6 with the oldest supported versions
+          pip_constraints: test_constraints_min_version.txt
+      - build_python:
+          name: python_3.7.3
+          executor: python373
+          pyversion: 3.7.3
+          # Test python 3.7 with the newest supported versions
+          pip_constraints: test_constraints_max_version.txt
       - markdown_link_check

docs/Installation-Windows.md

 
 [Download](https://www.anaconda.com/download/#windows) and install Anaconda for
 Windows. By using Anaconda, you can manage separate environments for different
-distributions of Python. Python 3.5 or 3.6 is required as we no longer support
+distributions of Python. Python 3.6.1 or higher is required as we no longer support
 Python 2. In this guide, we are using Python version 3.6 and Anaconda version
 5.1
 ([64-bit](https://repo.continuum.io/archive/Anaconda3-5.1.0-Windows-x86_64.exe)

docs/Installation.md

 
 ### Install Python and mlagents Package
 
-In order to use ML-Agents toolkit, you need Python 3.6.  
-[Download](https://www.python.org/downloads/) and install Python 3.6 if you do not already have it.
+In order to use ML-Agents toolkit, you need Python 3.6.1 or higher.  
+[Download](https://www.python.org/downloads/) and install the latest version of Python if you do not already have it.
 
 If your Python environment doesn't include `pip3`, see these
 [instructions](https://packaging.python.org/guides/installing-using-linux-tools/#installing-pip-setuptools-wheel-with-linux-package-managers)
 
 **Notes:**
 
-- We do not currently support Python 3.7 or Python 3.5.
+- We do not currently support Python 3.5 or lower.
 - If you are using Anaconda and are having trouble with TensorFlow, please see
   the following
   [link](https://www.tensorflow.org/install/pip)

ml-agents-envs/setup.py

         "Topic :: Scientific/Engineering :: Artificial Intelligence",
         "License :: OSI Approved :: Apache Software License",
         "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.7",
-        "Pillow>=4.2.1,<=5.4.1",
-        "numpy>=1.13.3,<=1.16.1",
-        "pytest>=3.2.2,<4.0.0",
-        "protobuf>=3.6,<3.7",
-        "grpcio>=1.11.0,<1.12.0",
+        "grpcio>=1.11.0",
+        "numpy>=1.13.3,<2.0",
+        "Pillow>=4.2.1",
+        "protobuf>=3.6",
-    python_requires=">=3.5,<3.8",
+    python_requires=">=3.5",
 )

ml-agents/setup.py

         "Topic :: Scientific/Engineering :: Artificial Intelligence",
         "License :: OSI Approved :: Apache Software License",
         "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.7",
     ],
     # find_namespace_packages will recurse through the directories and find all the packages
     packages=find_namespace_packages(
     install_requires=[
+        # Test-only dependencies should go in test_requirements.txt, not here.
+        "docopt",
+        "grpcio>=1.11.0",
+        "h5py>=2.9.0",
+        "jupyter",
+        "matplotlib",
-        "tensorflow>=1.7,<1.8",
+        "numpy>=1.13.3,<2.0",
-        "matplotlib",
-        "numpy>=1.13.3,<=1.14.5",
-        "jupyter",
-        "pytest>=3.2.2,<4.0.0",
-        "docopt",
+        "protobuf>=3.6",
-        "protobuf>=3.6,<3.7",
-        "grpcio>=1.11.0,<1.12.0",
-        "h5py>=2.9.0",
+        "tensorflow>=1.7,<2.0",
-    python_requires=">=3.6,<3.7",
+    python_requires=">=3.6.1",
     entry_points={"console_scripts": ["mlagents-learn=mlagents.trainers.learn:main"]},
 )

test_constraints_max_version.txt

+# pip constraints to use the *highest* versions allowed in ml-agents/setup.py
+# For projects with upper bounds, we should periodically update this list to the latest release version
+grpcio>=1.23.0
+numpy>=1.17.2
+tensorflow>=1.14.0

test_constraints_min_version.txt

+# pip constraints to use the *lowest* versions allowed in ml-agents/setup.py
+grpcio==1.11.0
+numpy==1.13.3
+Pillow==4.2.1
+protobuf==3.6
+tensorflow==1.7

test_requirements.txt

+# Test-only dependencies should go here, not in setup.py
+pytest>=3.2.2,<4.0.0
+pre-commit
+pytest-cov==2.6.1