For now, only one `pyodide` can be loaded in a given global scope because we need to use a global variable for package loading. This changes `loadPyodide` so that it no longer defines `globalThis.pyodide` in favor of just returning `pyodide` from `loadPyodide`. `Module` is placed on the global object as `globalThis.__pyodide_module` for the purposes of package loading. I added documentation to explicitly state that `loadPyodide` can only be run once in each global Javascript context, an error will be thrown otherwise.

This has two advantages: 
1. The returned `pyodide` module is understandable to Typescript and other code analysis, whereas the global variable is not understandable.
2. If in the future we are able to remove the global variable, no further API change will be needed (other than relaxing the documented "pyodide must be globally-unique" constraint). I figure it's better to make this API change earlier rather than later.

It will be possible to completely remove the global variable dependence when Firefox implements support for using ES6 modules in webworkers (see https://bugzilla.mozilla.org/show_bug.cgi?id=1247687).
API Don't expose pyodide as a global variable in loadPyodide. For now, only one `pyodide` can be loaded in a given global scope because we need to use a global variable for package loading. This changes `loadPyodide` so that it no longer defines `globalThis.pyodide` in favor of just returning `pyodide` from `loadPyodide`. `Module` is placed on the global object as `globalThis.__pyodide_module` for the purposes of package loading. I added documentation to explicitly state that `loadPyodide` can only be run once in each global Javascript context, an error will be thrown otherwise.

This has two advantages: 
1. The returned `pyodide` module is understandable to Typescript and other code analysis, whereas the global variable is not understandable.
2. If in the future we are able to remove the global variable, no further API change will be needed (other than relaxing the documented "pyodide must be globally-unique" constraint). I figure it's better to make this API change earlier rather than later.

It will be possible to completely remove the global variable dependence when Firefox implements support for using ES6 modules in webworkers (see https://bugzilla.mozilla.org/show_bug.cgi?id=1247687).
version: 2

defaults: &defaults
  working_directory: ~/repo
  docker:
    - image: pyodide/pyodide-env:16
  environment:
    - EMSDK_NUM_CORES: 3
      EMCC_CORES: 3
      PYODIDE_JOBS: 3

jobs:
  lint:
    <<: *defaults
    resource_class: small
    steps:
      - checkout

      - run:
          name: lint
          command: make lint

  test-docs:
    <<: *defaults
    resource_class: small
    steps:
      - checkout

      - run:
          name: Install prerequisites
          command: |
            pip install -r docs/requirements-doc.txt

      - run:
          name: Test docs
          command: pytest docs/sphinx_pyodide/tests

  build-core:
    <<: *defaults
    steps:
      - checkout

      - restore_cache:
          keys:
          - -{{ checksum "Makefile.envs" }}-v20201205-

      - run:
          name: build emsdk
          no_output_timeout: 1200
          command: |
            ccache -z
            make -C emsdk
            ccache -s

      - run:
          name: build cpython
          no_output_timeout: 1200
          command: |
            ccache -z
            make -C cpython
            ccache -s

      - run:
          name: build pyodide core
          no_output_timeout: 1200
          command: |
            ccache -z
            # The following packages are currently used in the main pyodide test suite
            PYODIDE_PACKAGES="micropip,pyparsing,pytz,packaging,kiwisolver" make
            ccache -s

      - run:
          name: check-size
          command: ls -lh build/

      - save_cache:
          paths:
            - ~/.ccache
          key: -{{ checksum "Makefile.envs" }}-v20201205-{{ .BuildNum }}

      - run:
          name: Clean up workspace
          command: |
            rm -rf cpython/{build,downloads}
            rm -rf emsdk/emsdk/binaryen

      - persist_to_workspace:
          root: .
          paths:
            - .


      - store_artifacts:
          path: /root/repo/build/

  build-packages:
    <<: *defaults
    steps:
      - checkout

      - attach_workspace:
          at: .

      - restore_cache:
          keys:
          - -{{ checksum "Makefile.envs" }}-v20201205-

      - run:
          name: build packages
          no_output_timeout: 1800
          command: |
            ccache -z
            make
            ccache -s

      - run:
          name: check-size
          command: ls -lh build/

      - save_cache:
          paths:
            - ~/.ccache
          key: -{{ checksum "Makefile.envs" }}-v20201205-{{ .BuildNum }}

      - persist_to_workspace:
          root: .
          paths:
            - ./packages/.artifacts
            - ./build

      - store_artifacts:
          path: /root/repo/build/

  test-core-firefox:
    <<: *defaults
    steps:
      - attach_workspace:
          at: .
      - run:
          name: test
          command: |
            tools/pytest_wrapper.py src packages/micropip/ -v -k firefox -n 3

  test-core-chrome:
    <<: *defaults
    steps:
      - attach_workspace:
          at: .
      - run:
          name: test
          command: |
            tools/pytest_wrapper.py src packages/micropip/ -v -k chrome

  test-packages-firefox:
    <<: *defaults
    steps:
      - attach_workspace:
          at: .
      - run:
          name: test
          command: |
            tools/pytest_wrapper.py packages/test* packages/*/test* -v -k firefox

  test-packages-chrome:
    <<: *defaults
    steps:
      - attach_workspace:
          at: .
      - run:
          name: test
          command: |
            tools/pytest_wrapper.py packages/test* packages/*/test* -v -k chrome -n 2

  test-emsdk:
    <<: *defaults
    resource_class: small
    steps:
      - attach_workspace:
          at: .
      - run:
          name: test
          command: make -C emsdk test

  test-python:
    <<: *defaults
    resource_class: small
    steps:
      - checkout
      - run:
          name: test
          command: |
            pytest src pyodide-build packages/micropip/ -v -k 'not (chrome or firefox)' --cov=pyodide_build --cov=pyodide

  benchmark:
    <<: *defaults
    steps:
      - checkout
      - attach_workspace:
          at: .
      - run:
          name: benchmark
          command: |
            python benchmark/benchmark.py /usr/local/bin/python3 build/benchmarks.json
      - store_artifacts:
          path: /root/repo/build/benchmarks.json

  deploy-release:
    # To reduce chance of deployment issues, try to keep the steps here as
    # similar as possible to the steps in deploy-dev!
    resource_class: small

    docker:
      - image: cibuilds/github:0.13

    steps:
      - checkout
      - attach_workspace:
          at: .
      - run:
          name: Install requirements
          command: |
            apk add --no-cache --update python3 make
            python3 -m pip install awscli
      - run:
          name: Deploy Github Releases
          command: |
            cp -r build /tmp/pyodide
            cd /tmp/
            tar cjf pyodide-build-${CIRCLE_TAG}.tar.bz2  pyodide/
            ghr -t "${GITHUB_TOKEN}" -u "${CIRCLE_PROJECT_USERNAME}" -r "${CIRCLE_PROJECT_REPONAME}" -c "${CIRCLE_SHA1}" -delete  "${CIRCLE_TAG}" ./pyodide-build-${CIRCLE_TAG}.tar.bz2

      - run:
          name: Set PYODIDE_BASE_URL
          command: PYODIDE_BASE_URL="https://cdn.jsdelivr.net/pyodide/v${CIRCLE_TAG}/full/" make update_base_url
      - run:
          name: Deploy to pyodide-cdn2.iodide.io
          command: |
            find build/ -type f -exec sh -c "echo \"Compressing {}\"; gzip {}; mv {}.gz {};" \;
            aws s3 sync build/ "s3://pyodide-cdn2.iodide.io/v${CIRCLE_TAG}/full/" --exclude '*.data' --cache-control 'max-age=30758400, immutable, public' --content-encoding 'gzip'    # 1 year cache
            aws s3 sync build/ "s3://pyodide-cdn2.iodide.io/v${CIRCLE_TAG}/full/" --exclude '*' --include '*.data' --cache-control 'max-age=30758400, immutable, public'  --content-type 'application/wasm' --content-encoding 'gzip'  # 1 year
            # update 301 redirect for the /latest/* route.
            aws s3api put-bucket-website --cli-input-json file://.circleci/s3-website-config.json

  deploy-dev:
    # To reduce chance of deployment issues, try to keep the steps here as
    # similar as possible to the steps in deploy-release!
    resource_class: small

    docker:
      - image: cibuilds/github:0.13

    steps:
      - checkout
      - attach_workspace:
          at: .
      - run:
          name: Install requirements
          command: |
            apk add --no-cache --update python3 make
            python3 -m pip install awscli
      - run:
          name: Set PYODIDE_BASE_URL
          command: PYODIDE_BASE_URL="https://cdn.jsdelivr.net/pyodide/dev/full/" make update_base_url
      - run:
          name: Deploy to pyodide-cdn2.iodide.io
          command: |
            find build/ -type f -exec sh -c "echo \"Compressing {}\"; gzip {}; mv {}.gz {};" \;
            aws s3 rm --recursive "s3://pyodide-cdn2.iodide.io/dev/full/"
            aws s3 sync build/ "s3://pyodide-cdn2.iodide.io/dev/full/" --exclude '*.data' --cache-control 'max-age=3600, public' --content-encoding 'gzip'  # 1 hour cache
            aws s3 sync build/ "s3://pyodide-cdn2.iodide.io/dev/full/" --exclude '*' --include '*.data' --cache-control 'max-age=3600, public'  --content-type 'application/wasm' --content-encoding 'gzip'  # 1 hour cache

workflows:
  version: 2
  build-and-deploy:
    jobs:
      - lint
      - test-docs
      - build-core:
          filters:
            tags:
              only: /.*/
      - build-packages:
          requires:
            - build-core
          filters:
            tags:
              only: /.*/
      - test-core-chrome:
          requires:
            - build-core
          filters:
            tags:
              only: /.*/
      - test-core-firefox:
          requires:
            - build-core
          filters:
            tags:
              only: /.*/
      - test-packages-chrome:
          requires:
            - build-packages
          filters:
            tags:
              only: /.*/
      - test-packages-firefox:
          requires:
            - build-packages
          filters:
            tags:
              only: /.*/
      - test-emsdk:
          requires:
            - build-core
          filters:
            tags:
              only: /.*/
      - test-python:
          filters:
            tags:
              only: /.*/
      - benchmark:
          requires:
            - build-packages
      - deploy-release:
          requires:
            - lint
            - test-python
            - test-core-firefox
            - test-packages-firefox
            - test-emsdk
          filters:
            branches:
              ignore: /.*/
            tags:
              only: /^\d+\.\d+\.\w+$/
      - deploy-dev:
          requires:
            - lint
            - test-python
            - test-core-firefox
            - test-packages-firefox
            - test-emsdk
          filters:
            branches:
              only: main

version: 2

defaults: &defaults
  working_directory: ~/repo
  docker:
    - image: pyodide/pyodide-env:16
  environment:
    - EMSDK_NUM_CORES: 3
      EMCC_CORES: 3
      PYODIDE_JOBS: 3

jobs:
  lint:
    <<: *defaults
    resource_class: small
    steps:
      - checkout

      - run:
          name: lint
          command: make lint

  test-docs:
    <<: *defaults
    resource_class: small
    steps:
      - checkout

      - run:
          name: Install prerequisites
          command: |
            pip install -r docs/requirements-doc.txt

      - run:
          name: Test docs
          command: pytest docs/sphinx_pyodide/tests

  build-core:
    <<: *defaults
    steps:
      - checkout

      - restore_cache:
          keys:
          - -{{ checksum "Makefile.envs" }}-v20201205-

      - run:
          name: build emsdk
          no_output_timeout: 1200
          command: |
            ccache -z
            make -C emsdk
            ccache -s

      - run:
          name: build cpython
          no_output_timeout: 1200
          command: |
            ccache -z
            make -C cpython
            ccache -s

      - run:
          name: build pyodide core
          no_output_timeout: 1200
          command: |
            ccache -z
            # The following packages are currently used in the main pyodide test suite
            PYODIDE_PACKAGES="micropip,pyparsing,pytz,packaging,kiwisolver" make
            ccache -s

      - run:
          name: check-size
          command: ls -lh build/

      - save_cache:
          paths:
            - ~/.ccache
          key: -{{ checksum "Makefile.envs" }}-v20201205-{{ .BuildNum }}

      - run:
          name: Clean up workspace
          command: |
            rm -rf cpython/{build,downloads}
            rm -rf emsdk/emsdk/binaryen

      - persist_to_workspace:
          root: .
          paths:
            - .


      - store_artifacts:
          path: /root/repo/build/

  build-packages:
    <<: *defaults
    steps:
      - checkout

      - attach_workspace:
          at: .

      - restore_cache:
          keys:
          - -{{ checksum "Makefile.envs" }}-v20201205-

      - run:
          name: build packages
          no_output_timeout: 1800
          command: |
            ccache -z
            make
            ccache -s

      - run:
          name: check-size
          command: ls -lh build/

      - save_cache:
          paths:
            - ~/.ccache
          key: -{{ checksum "Makefile.envs" }}-v20201205-{{ .BuildNum }}

      - persist_to_workspace:
          root: .
          paths:
            - ./packages/.artifacts
            - ./build

      - store_artifacts:
          path: /root/repo/build/

  test-core-firefox:
    <<: *defaults
    steps:
      - attach_workspace:
          at: .
      - run:
          name: test
          command: |
            tools/pytest_wrapper.py src packages/micropip/ -v -k firefox -n 3

  test-core-chrome:
    <<: *defaults
    steps:
      - attach_workspace:
          at: .
      - run:
          name: test
          command: |
            tools/pytest_wrapper.py src packages/micropip/ -v -k chrome

  test-packages-firefox:
    <<: *defaults
    steps:
      - attach_workspace:
          at: .
      - run:
          name: test
          command: |
            tools/pytest_wrapper.py packages/test* packages/*/test* -v -k firefox

  test-packages-chrome:
    <<: *defaults
    steps:
      - attach_workspace:
          at: .
      - run:
          name: test
          command: |
            tools/pytest_wrapper.py packages/test* packages/*/test* -v -k chrome -n 2

  test-emsdk:
    <<: *defaults
    resource_class: small
    steps:
      - attach_workspace:
          at: .
      - run:
          name: test
          command: make -C emsdk test

  test-python:
    <<: *defaults
    resource_class: small
    steps:
      - checkout
      - run:
          name: test
          command: |
            pytest src pyodide-build packages/micropip/ -v -k 'not (chrome or firefox)' --cov=pyodide_build --cov=pyodide

  benchmark:
    <<: *defaults
    steps:
      - checkout
      - attach_workspace:
          at: .
      - run:
          name: benchmark
          command: |
            python benchmark/benchmark.py /usr/local/bin/python3 build/benchmarks.json
      - store_artifacts:
          path: /root/repo/build/benchmarks.json

  deploy-release:
    # To reduce chance of deployment issues, try to keep the steps here as
    # similar as possible to the steps in deploy-dev!
    resource_class: small

    docker:
      - image: cibuilds/github:0.13

    steps:
      - checkout
      - attach_workspace:
          at: .
      - run:
          name: Install requirements
          command: |
            apk add --no-cache --update python3 make
            python3 -m pip install awscli
      - run:
          name: Deploy Github Releases
          command: |
            cp -r build /tmp/pyodide
            cd /tmp/
            tar cjf pyodide-build-${CIRCLE_TAG}.tar.bz2  pyodide/
            ghr -t "${GITHUB_TOKEN}" -u "${CIRCLE_PROJECT_USERNAME}" -r "${CIRCLE_PROJECT_REPONAME}" -c "${CIRCLE_SHA1}" -delete  "${CIRCLE_TAG}" ./pyodide-build-${CIRCLE_TAG}.tar.bz2

      - run:
          name: Set PYODIDE_BASE_URL
          command: PYODIDE_BASE_URL="https://cdn.jsdelivr.net/pyodide/v${CIRCLE_TAG}/full/" make update_base_url
      - run:
          name: Deploy to pyodide-cdn2.iodide.io
          command: |
            find build/ -type f -exec sh -c "echo \"Compressing {}\"; gzip {}; mv {}.gz {};" \;
            aws s3 sync build/ "s3://pyodide-cdn2.iodide.io/v${CIRCLE_TAG}/full/" --exclude '*.data' --cache-control 'max-age=30758400, immutable, public' --content-encoding 'gzip'    # 1 year cache
            aws s3 sync build/ "s3://pyodide-cdn2.iodide.io/v${CIRCLE_TAG}/full/" --exclude '*' --include '*.data' --cache-control 'max-age=30758400, immutable, public'  --content-type 'application/wasm' --content-encoding 'gzip'  # 1 year
            # update 301 redirect for the /latest/* route.
            aws s3api put-bucket-website --cli-input-json file://.circleci/s3-website-config.json

  deploy-dev:
    # To reduce chance of deployment issues, try to keep the steps here as
    # similar as possible to the steps in deploy-release!
    resource_class: small

    docker:
      - image: cibuilds/github:0.13

    steps:
      - checkout
      - attach_workspace:
          at: .
      - run:
          name: Install requirements
          command: |
            apk add --no-cache --update python3 make
            python3 -m pip install awscli
      - run:
          name: Set PYODIDE_BASE_URL
          command: PYODIDE_BASE_URL="https://cdn.jsdelivr.net/pyodide/dev/full/" make update_base_url
      - run:
          name: Deploy to pyodide-cdn2.iodide.io
          command: |
            find build/ -type f -exec sh -c "echo \"Compressing {}\"; gzip {}; mv {}.gz {};" \;
            aws s3 rm --recursive "s3://pyodide-cdn2.iodide.io/dev/full/"
            aws s3 sync build/ "s3://pyodide-cdn2.iodide.io/dev/full/" --exclude '*.data' --cache-control 'max-age=3600, public' --content-encoding 'gzip'  # 1 hour cache
            aws s3 sync build/ "s3://pyodide-cdn2.iodide.io/dev/full/" --exclude '*' --include '*.data' --cache-control 'max-age=3600, public'  --content-type 'application/wasm' --content-encoding 'gzip'  # 1 hour cache

workflows:
  version: 2
  build-and-deploy:
    jobs:
      - lint
      - test-docs
      - build-core:
          filters:
            tags:
              only: /.*/
      - build-packages:
          requires:
            - build-core
          filters:
            tags:
              only: /.*/
      - test-core-chrome:
          requires:
            - build-core
          filters:
            tags:
              only: /.*/
      - test-core-firefox:
          requires:
            - build-core
          filters:
            tags:
              only: /.*/
      - test-packages-chrome:
          requires:
            - build-packages
          filters:
            tags:
              only: /.*/
      - test-packages-firefox:
          requires:
            - build-packages
          filters:
            tags:
              only: /.*/
      - test-emsdk:
          requires:
            - build-core
          filters:
            tags:
              only: /.*/
      - test-python:
          filters:
            tags:
              only: /.*/
      - benchmark:
          requires:
            - build-packages
      - deploy-release:
          requires:
            - lint
            - test-python
            - test-core-firefox
            - test-packages-firefox
            - test-emsdk
          filters:
            branches:
              ignore: /.*/
            tags:
              only: /^\d+\.\d+\.\w+$/
      - deploy-dev:
          requires:
            - lint
            - test-python
            - test-core-firefox
            - test-packages-firefox
            - test-emsdk
          filters:
            branches:
              only: main
