docs: generate docs for all stable versions

This generate the documentation of all versions from git tags

This uses a fresh database for running doc build and
don't hardcode the doc source directory.

Closes-Bug: #1566709
Change-Id: I9d0f1fcb2fe44177d95dee0915e849e48155f53d

doc/source/conf.py

@@ -178,3 +178,10 @@ html_static_path = ['_static']
 
 # Output file base name for HTML help builder.
 htmlhelp_basename = 'gnocchidoc'
+
+# Multiversion docs
+scv_sort = ('semver',)
+scv_greatest_tag = True
+scv_priority = 'branches'
+scv_whitelist_branches = ('master',)
+scv_whitelist_tags = ('3.1.0', '3.0.4', '2.2.1')

gnocchi/gendoc.py

@@ -15,6 +15,10 @@
 # under the License.
 from __future__ import absolute_import
 import json
+import os
+import subprocess
+import sys
+import tempfile
 
 import jinja2
 import six
@@ -24,7 +28,6 @@ import yaml
 
 from gnocchi.tests import test_rest
 
-
 # HACK(jd) Not sure why but Sphinx setup this multiple times, so we just avoid
 # doing several times the requests by using this global variable :(
 _RUN = False
@@ -103,10 +106,44 @@ class ScenarioList(list):
         return super(ScenarioList, self).__getitem__(key)
 
 
+multiversion_hack = """
+import sys
+import os
+
+srcdir = os.path.join("%s", "..", "..")
+os.chdir(srcdir)
+sys.path.insert(0, srcdir)
+
+class FakeApp(object):
+    def info(self, *args, **kwasrgs):
+        pass
+
+import gnocchi.gendoc
+gnocchi.gendoc.setup(FakeApp())
+"""
+
+
 def setup(app):
     global _RUN
     if _RUN:
         return
+
+    # NOTE(sileht): On gnocchi.xyz, we build a multiversion of the docs
+    # all versions are built with the master gnocchi.gendoc sphinx extension.
+    # So the hack here run an other python script to generate the rest.rst
+    # file of old version of the module.
+    # It also drop the database before each run.
+    if sys.argv[0].endswith("sphinx-versioning"):
+        subprocess.call(["dropdb", os.environ['PGDATABASE']])
+        subprocess.call(["createdb", os.environ['PGDATABASE']])
+
+        with tempfile.NamedTemporaryFile() as f:
+            f.write(multiversion_hack % app.confdir)
+            f.flush()
+            subprocess.call(['python', f.name])
+        _RUN = True
+        return
+
     webapp = _setup_test_app()
     # TODO(jd) Do not hardcode doc/source
     with open("doc/source/rest.yaml") as f:

tox.ini

@@ -140,5 +140,9 @@ commands = doc8 --ignore-path doc/source/rest.rst doc/source
 [testenv:docs-gnocchi.xyz]
 deps = .[file,postgresql,test,doc]
        sphinx_rtd_theme
+       sphinxcontrib-versioning
+# for 2.x doc
+       pytimeparse
+       retrying
 commands =
-    pifpaf -g GNOCCHI_INDEXER_URL run postgresql -- sphinx-build -D html_theme=sphinx_rtd_theme doc/source doc/build/html
+    pifpaf -g GNOCCHI_INDEXER_URL run postgresql -- sphinx-versioning build doc/source doc/build/html -- -D html_theme=sphinx_rtd_theme