tests/vm: Added configuration file support

Changes to tests/vm/basevm.py to allow accepting a configuration file
as a parameter. Allows for specifying VM options such as
cpu, machine, memory, and arbitrary qemu arguments for specifying options
such as NUMA configuration.
Also added an example conf_example_aarch64.yml and conf_example_x86.yml.

Signed-off-by: Robert Foley <robert.foley@linaro.org>
Reviewed-by: Peter Puhov <peter.puhov@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200601211421.1277-4-robert.foley@linaro.org>
Message-Id: <20200701135652.1366-8-alex.bennee@linaro.org>

1 files changed, 39 insertions, 1 deletions

diff --git a/tests/vm/basevm.py b/tests/vm/basevm.py
index 5ae39ad113..f3a8fbbe34 100644
--- a/tests/vm/basevm.py
+++ b/tests/vm/basevm.py
@@ -481,7 +481,6 @@ class BaseVM(object):
                               cwd=cidir,
                               stdin=self._devnull, stdout=self._stdout,
                               stderr=self._stdout)
-
         return os.path.join(cidir, "cloud-init.iso")
 
 def get_qemu_path(arch, build_path=None):
@@ -497,6 +496,41 @@ def get_qemu_path(arch, build_path=None):
         qemu_path = "qemu-system-" + arch
     return qemu_path
 
+def parse_config(config, args):
+    """ Parse yaml config and populate our config structure.
+        The yaml config allows the user to override the
+        defaults for VM parameters.  In many cases these
+        defaults can be overridden without rebuilding the VM."""
+    if args.config:
+        config_file = args.config
+    elif 'QEMU_CONFIG' in os.environ:
+        config_file = os.environ['QEMU_CONFIG']
+    else:
+        return config
+    if not os.path.exists(config_file):
+        raise Exception("config file {} does not exist".format(config_file))
+    # We gracefully handle importing the yaml module
+    # since it might not be installed.
+    # If we are here it means the user supplied a .yml file,
+    # so if the yaml module is not installed we will exit with error.
+    try:
+        import yaml
+    except ImportError:
+        print("The python3-yaml package is needed "\
+              "to support config.yaml files")
+        # Instead of raising an exception we exit to avoid
+        # a raft of messy (expected) errors to stdout.
+        exit(1)
+    with open(config_file) as f:
+        yaml_dict = yaml.safe_load(f)
+
+    if 'qemu-conf' in yaml_dict:
+        config.update(yaml_dict['qemu-conf'])
+    else:
+        raise Exception("config file {} is not valid"\
+                        " missing qemu-conf".format(config_file))
+    return config
+
 def parse_args(vmcls):
 
     def get_default_jobs():
@@ -536,6 +570,9 @@ def parse_args(vmcls):
                       help="run tests with a snapshot")
     parser.add_option("--genisoimage", default="genisoimage",
                       help="iso imaging tool")
+    parser.add_option("--config", "-c", default=None,
+                      help="Provide config yaml for configuration. "\
+                           "See config_example.yaml for example.")
     parser.disable_interspersed_args()
     return parser.parse_args()
 
@@ -547,6 +584,7 @@ def main(vmcls, config=None):
         if not argv and not args.build_qemu and not args.build_image:
             print("Nothing to do?")
             return 1
+        config = parse_config(config, args)
         logging.basicConfig(level=(logging.DEBUG if args.debug
                                    else logging.WARN))
         vm = vmcls(args, config=config)