add api ref and doc link validation to release

This patch adds a linkcheck target to our tox.ini that validates URLs
in both our doc and api-ref html. In addition the release checklist is
updated to suggest this should be done prior to releasing.

Partial-Bug: #1716005

Change-Id: I48b4dde3ffd1902a31bf6f352b7143d4c15f3443

api-ref/source/conf.py

@@ -228,3 +228,10 @@ latex_documents = [
 
 # If false, no module index is generated.
 # latex_use_modindex = True
+
+linkcheck_anchors_ignore = [
+    # skip gerrit anchors
+    '\/q\/.*',
+    'q\,.*',
+    '\/c\/.*'
+]

doc/source/conf.py

@@ -233,3 +233,10 @@ html_last_updated_fmt = '%Y-%m-%d %H:%M'
 repository_name = 'openstack/neutron-lib'
 bug_project = 'neutron'
 bug_tag = 'doc'
+
+linkcheck_anchors_ignore = [
+    # skip gerrit anchors
+    '\/q\/.*',
+    'q\,.*',
+    '\/c\/.*'
+]

doc/source/contributor/releasing.rst

@@ -29,3 +29,7 @@ dashboard can give you a glimpse into the sanity of the integration between
 neutron-lib and the Stadium projects, and can be considered the quick check
 before going ahead with a full blown sentinel patch. Periodic failures can be
 debugged by viewing the `periodic logs <http://logs.openstack.org/periodic>`_
+
+In addition, both the API reference as well as the project docs should be
+validated to ensure there are no dead links. To do so run
+``tox -e linkcheck`` and address the errors.

tox.ini

@@ -41,6 +41,14 @@ commands =
   rm -rf api-ref/build
   sphinx-build -W -b html -d api-ref/build/doctrees api-ref/source api-ref/build/html
 
+[testenv:linkcheck]
+whitelist_externals = rm
+commands =
+  rm -rf api-ref/build
+  sphinx-build -W -b linkcheck api-ref/source api-ref/build/linkcheck
+  rm -rf doc/build
+  sphinx-build -W -b linkcheck doc/source doc/build/linkcheck
+
 [testenv:debug]
 commands = oslo_debug_helper -t neutron_lib/tests/unit {posargs}