From d410953d664ba1138a22da3f7f37b59efc227ae5 Mon Sep 17 00:00:00 2001
From: Daniel Rasmussen <daniel.rasmussen@appliedbrainresearch.com>
Date: Wed, 18 Mar 2020 14:50:00 -0300
Subject: [PATCH] Add exponential backoff extension

---
 .nengobones.yml                   |  1 +
 CHANGES.rst                       |  3 +++
 docs/conf.py                      |  2 ++
 docs/extensions.rst               |  5 +++++
 nengo_sphinx_theme/ext/backoff.py | 33 +++++++++++++++++++++++++++++++
 setup.py                          |  1 +
 6 files changed, 45 insertions(+)
 create mode 100644 nengo_sphinx_theme/ext/backoff.py

diff --git a/.nengobones.yml b/.nengobones.yml
index 10b1c26..97e6875 100644
--- a/.nengobones.yml
+++ b/.nengobones.yml
@@ -38,6 +38,7 @@ setup_py:
   include_package_data: True
   install_req:
     - sphinx>=1.8
+    - backoff>=1.10.0
   docs_req:
     - jupyter
     - matplotlib
diff --git a/CHANGES.rst b/CHANGES.rst
index 7e18146..d9a62d3 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -28,6 +28,9 @@ Release History
   ``nengo_sphinx_theme.ext.autoautosummary``, which allows classes/functions
   documented with ``autoautosummary`` or ``automodule`` to be moved to a different
   nominal namespace. (`#52 <https://github.com/nengo/nengo-sphinx-theme/pull/52>`__)
+- Added ``nengo_sphinx_theme.ext.backoff``, which monkeypatches the Sphinx
+  HTTP request functionality to add exponential backoff.
+  (`#53 <https://github.com/nengo/nengo-sphinx-theme/pull/53>`__)
 
 1.2.0 (November 14, 2019)
 =========================
diff --git a/docs/conf.py b/docs/conf.py
index c2e3fb5..529be5e 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -17,6 +17,7 @@
     "sphinx.ext.viewcode",
     "nbsphinx",
     "nengo_sphinx_theme",
+    "nengo_sphinx_theme.ext.backoff",
     "nengo_sphinx_theme.ext.redirects",
     "numpydoc",
     "nengo_sphinx_theme.ext.resolvedefaults",
@@ -72,6 +73,7 @@
 linkcheck_anchors = True
 default_role = "py:obj"
 pygments_style = "sphinx"
+user_agent = "nengo_sphinx_theme"
 
 project = "Nengo Sphinx Theme"
 authors = "Applied Brain Research"
diff --git a/docs/extensions.rst b/docs/extensions.rst
index 7780767..a71ac03 100644
--- a/docs/extensions.rst
+++ b/docs/extensions.rst
@@ -48,3 +48,8 @@ Redirects
 
 The following page should redirect to the
 `deeply nested testing page <redirect/to/nested-page.html>`_.
+
+Backoff
+=======
+
+.. automodule:: nengo_sphinx_theme.ext.backoff
diff --git a/nengo_sphinx_theme/ext/backoff.py b/nengo_sphinx_theme/ext/backoff.py
new file mode 100644
index 0000000..fd79ded
--- /dev/null
+++ b/nengo_sphinx_theme/ext/backoff.py
@@ -0,0 +1,33 @@
+"""
+Monkeypatches the Sphinx HTTP request functions to add exponential backoff.
+
+The main use case for this is to avoid server-side rejections caused by too many
+requests when running the linkchecker.
+"""
+
+import requests
+
+import backoff
+from sphinx.util import requests as sphinx_requests
+from sphinx.util.requests import get, head
+
+
+@backoff.on_predicate(backoff.expo, lambda x: x.status_code == 429, max_time=60)
+@backoff.on_exception(
+    backoff.constant, requests.exceptions.RequestException, max_tries=3,
+)
+def get_with_backoff(*args, **kwargs):
+    return get(*args, **kwargs)
+
+
+@backoff.on_predicate(backoff.expo, lambda x: x.status_code == 429, max_time=60)
+@backoff.on_exception(
+    backoff.constant, requests.exceptions.RequestException, max_tries=3,
+)
+def head_with_backoff(*args, **kwargs):
+    return head(*args, **kwargs)
+
+
+def setup(_):
+    sphinx_requests.get = get_with_backoff
+    sphinx_requests.head = head_with_backoff
diff --git a/setup.py b/setup.py
index abbe471..dae3696 100755
--- a/setup.py
+++ b/setup.py
@@ -33,6 +33,7 @@ def read(*filenames, **kwargs):
 
 install_req = [
     "sphinx>=1.8",
+    "backoff>=1.10.0",
 ]
 docs_req = [
     "jupyter",