Improve the UX around sample config generation

This commit just adds some documentation around using the sample config
generator. It also adds a wrapper script that sets the env variable for
running the oslo generator script with tempest.

Change-Id: I860b17defeeb85174e68b1e8b046b0e43c30683b

HACKING.rst

@@ -186,3 +186,9 @@ Good candidates for stress tests are:
 
 - Scenario tests
 - API tests that have a wide focus
+
+Sample Configuration File
+-------------------------
+The sample config file is autogenerated using a script. If any changes are made
+to the config variables in tempest then the sample config file must be
+regenerated. This can be done running the script: tools/generate_sample.sh

README.rst

@@ -79,6 +79,9 @@ Detailed configuration of tempest is beyond the scope of this
 document. The etc/tempest.conf.sample attempts to be a self
 documenting version of the configuration.
 
+The sample config file is auto generated using the script:
+tools/generate_sample.sh
+
 The most important pieces that are needed are the user ids, openstack
 endpoints, and basic flavors and images needed to run tests.
 

tempest/common/generate_sample_tempest.py

@@ -21,6 +21,15 @@ import sys
 from tempest import config
 from tempest.openstack.common.config import generator
 
+# NOTE(mtreinish): This hack is needed because of how oslo config is used in
+# tempest. Tempest is run from inside a test runner and so we can't rely on the
+# global CONF object being fully populated when we run a test. (test runners
+# don't init every file for running a test) So to get around that we manually
+# load the config file in tempest for each test class to ensure that every
+# config option is set. However, the tool expects the CONF object to be fully
+# populated when it inits all the files in the project. This just works around
+# the issue by manually loading the config file (which may or may not exist)
+# which will populate all the options before running the generator.
 
 config.TempestConfig()
 generator.generate(sys.argv[1:])

tools/config/check_uptodate.sh

@@ -5,6 +5,6 @@ tools/config/generate_sample.sh -b ./ -p tempest -o $TEMPDIR
 if ! diff $TEMPDIR/$CFGFILE etc/$CFGFILE
 then
     echo "E: tempest.conf.sample is not up to date, please run:"
-    echo "MODULEPATH=tempest.common.generate_sample_tempest tools/config/generate_sample.sh"
+    echo "tools/generate_sample.sh"
     exit 42
 fi

tools/generate_sample.sh

@@ -0,0 +1,2 @@
+#!/bin/sh
+MODULEPATH=tempest.common.generate_sample_tempest tools/config/generate_sample.sh $@