Fix auto build of docs (#1217)

PR #1193 introduced a bug with readthedocs.org in relying on presenting
the MIN_PY_VER env var via the Makefile. However the Makefile isn't
invoked during automated build of readthedocs.

This commit fixes automatic builds of our docs again.

.ci/variables.json

@@ -1,6 +1,7 @@
 {
   "python_versions": {
     "PY38": "3.8.8",
-    "PY39": "3.9.2"
+    "PY39": "3.9.2",
+    "MIN_PY_VER": "3.8.8"
   }
 }

Makefile

@@ -23,7 +23,6 @@ PY_BIN = python3
 PIP_WRAPPER = $(PY_BIN) -m pip
 export PY38 = $(shell jq -r '.python_versions.PY38' .ci/variables.json)
 export PY39 = $(shell jq -r '.python_versions.PY39' .ci/variables.json)
-export MIN_PY_VER = $(PY38)
 VENV_NAME ?= .venv
 VENV_ACTIVATE_FILE = $(VENV_NAME)/bin/activate
 VENV_ACTIVATE = . $(VENV_ACTIVATE_FILE)

docs/conf.py

@@ -23,6 +23,8 @@
 from datetime import date
 from os.path import join, dirname
 
+from sphinx.config import ConfigError
+
 # -- General configuration ------------------------------------------------
 
 # Add any Sphinx extension module names here, as strings. They can be
@@ -41,9 +43,17 @@
 master_doc = 'index'
 language = None
 
+CI_VARS = os.path.join(os.path.dirname(os.path.abspath(__file__)), "..", ".ci", "variables.json")
+
 
 def read_min_python_version():
-    return os.environ["MIN_PY_VER"]
+    try:
+        with open(CI_VARS, "rt") as fp:
+            return json.load(fp)["python_versions"]["MIN_PY_VER"]
+    except KeyError as e:
+        raise ConfigError(
+            f"Failed building docs as required key [{e}] couldn't be found in the file [{CI_VARS}]."
+        )
 
 
 GLOBAL_SUBSTITUTIONS = {

it/installation_test.py

@@ -16,33 +16,22 @@
 # under the License.
 
 """
-These tests ensure the validatity of Rally installation instructions (as shown in docs)
+These tests ensure the validity of Rally installation instructions (as shown in docs)
 """
 
 import json
 import os
-import warnings
 
 import it
 
 ROOT_DIR = os.path.abspath(os.path.join(os.path.dirname(__file__), '..'))
 _CI_VARS = ".ci/variables.json"
 
-# normally set by Makefile, be lenient to allow running from IDE
-MIN_PY_VER = os.environ.get("MIN_PY_VER")
-if not MIN_PY_VER:
-    with open(os.path.join(ROOT_DIR, _CI_VARS), "rt") as fp:
-        try:
-            MIN_PY_VER = json.load(fp)["python_versions"]["PY38"]
-            warnings.warn(
-                f"Environment variable [MIN_PY_VER] is missing. You should fix this problem "
-                f"if you are running these tests "
-                f"on anything else than through your IDE. Defaulting to [{MIN_PY_VER}].",
-                category=RuntimeWarning
-            )
-        except KeyError:
-            raise EnvironmentError(f"Installation tests require [python_versions.PY38] key in [{_CI_VARS}] or"
-                                   f"the [MIN_PY_VER] environment variable set.")
+with open(os.path.join(ROOT_DIR, _CI_VARS), "rt") as fp:
+    try:
+        MIN_PY_VER = json.load(fp)["python_versions"]["MIN_PY_VER"]
+    except KeyError:
+        raise EnvironmentError(f"Installation tests require [python_versions.MIN_PY_VER] key in [{_CI_VARS}]")
 
 
 def test_installs_inside_venv():

tox.ini

@@ -22,7 +22,6 @@ passenv =
     JAVA13_HOME
     JAVA14_HOME
     JAVA15_HOME
-    MIN_PY_VER
     RALLY_HOME
     SSH_AUTH_SOCK
     THESPLOG_FILE