[ci] move link checking to a cron job (#3890)

* [ci] move link checking to a cron job

* run once to register

* set PYTHON_VERSION

* actually build docs

* uncomment

* remove stuff

* Update docs/.linkcheckerrc

* condense

* remove PR triggers again

* Update .github/workflows/linkchecker.yml

* move TASK

.ci/test.sh

@@ -18,7 +18,7 @@ source activate $CONDA_ENV
 
 cd $BUILD_DIRECTORY
 
-if [[ $TASK == "check-docs" ]]; then
+if [[ $TASK == "check-docs" ]] || [[ $TASK == "check-links" ]]; then
     cd $BUILD_DIRECTORY/docs
     conda install -q -y -n $CONDA_ENV -c conda-forge doxygen
     pip install --user -r requirements.txt linkchecker rstcheck
@@ -27,9 +27,13 @@ if [[ $TASK == "check-docs" ]]; then
     rstcheck --report warning `find . -type f -name "*.rst"` || exit -1
     cd $BUILD_DIRECTORY/docs
     rstcheck --report warning --ignore-directives=autoclass,autofunction,doxygenfile `find . -type f -name "*.rst"` || exit -1
-    # build docs and check them for broken links
+    # build docs
     make html || exit -1
+    if [[ $TASK == "check-links" ]]; then
+        # check docs for broken links
         linkchecker --config=.linkcheckerrc ./_build/html/*.html || exit -1
+        exit 0
+    fi
     # check the consistency of parameters' descriptions and other stuff
     cp $BUILD_DIRECTORY/docs/Parameters.rst $BUILD_DIRECTORY/docs/Parameters-backup.rst
     cp $BUILD_DIRECTORY/src/io/config_auto.cpp $BUILD_DIRECTORY/src/io/config_auto-backup.cpp

.github/workflows/linkchecker.yml

+name: Link checks
+
+on:
+  # Run manually by clicking a button in the UI
+  workflow_dispatch:
+  # Run every 8 hours
+  schedule:
+    - cron: '0 8 * * *'
+
+env:
+  CONDA_ENV: test-env
+  GITHUB_ACTIONS: 'true'
+  OS_NAME: 'linux'
+  PYTHON_VERSION: 3.9
+  TASK: 'check-links'
+
+jobs:
+  check-links:
+    timeout-minutes: 60
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2.3.4
+        with:
+          fetch-depth: 5
+          submodules: false
+      - name: Check that all tests succeeded
+        run: |
+          export BUILD_DIRECTORY="$GITHUB_WORKSPACE"
+          export CONDA=${HOME}/miniconda
+          export PATH=${CONDA}/bin:${HOME}/.local/bin:${PATH}
+          $GITHUB_WORKSPACE/.ci/setup.sh || exit -1
+          $GITHUB_WORKSPACE/.ci/test.sh || exit -1

README.md

@@ -10,6 +10,7 @@ Light Gradient Boosting Machine
 [![Azure Pipelines Build Status](https://lightgbm-ci.visualstudio.com/lightgbm-ci/_apis/build/status/Microsoft.LightGBM?branchName=master)](https://lightgbm-ci.visualstudio.com/lightgbm-ci/_build/latest?definitionId=1)
 [![Appveyor Build Status](https://ci.appveyor.com/api/projects/status/1ys5ot401m0fep6l/branch/master?svg=true)](https://ci.appveyor.com/project/guolinke/lightgbm/branch/master)
 [![Documentation Status](https://readthedocs.org/projects/lightgbm/badge/?version=latest)](https://lightgbm.readthedocs.io/)
+![Link checks](https://github.com/microsoft/LightGBM/workflows/Link%20checks/badge.svg)
 [![License](https://img.shields.io/github/license/microsoft/lightgbm.svg)](https://github.com/microsoft/LightGBM/blob/master/LICENSE)
 [![Python Versions](https://img.shields.io/pypi/pyversions/lightgbm.svg?logo=python&logoColor=white)](https://pypi.org/project/lightgbm)
 [![PyPI Version](https://img.shields.io/pypi/v/lightgbm.svg?logo=pypi&logoColor=white)](https://pypi.org/project/lightgbm)

docs/.linkcheckerrc

@@ -3,6 +3,7 @@ maxrequestspersecond=1
 recursionlevel=1
 anchors=1
 sslverify=0
+threads=1
 
 [filtering]
 ignore=