Verify-license plugin support

Current StarlingX implementation does not support a proper
license validation.
Used the Stevedore plugin pattern to allow override
of the verify-license implementation to add enhanced
validation rules if necessary.

Story: 2007403
Task: 39644

Change-Id: I6fa6626feabff06b832dd41a2778804a28956131
Signed-off-by: Carmen Rata <carmen.rata@windriver.com>

utilities/platform-util/platform-util/platform_util/license/base.py

@@ -0,0 +1,24 @@
+#
+# Copyright (c) 2020 Wind River Systems, Inc.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+import abc
+import six
+
+
+@six.add_metaclass(abc.ABCMeta)
+class BaseLicense(object):
+    """Base class for license validation operations.
+    """
+
+    @abc.abstractmethod
+    def verify_license(self, *args):
+        """Validate license file
+
+        :param : variable number of parameters
+        """
+
+    def __init__(self, operator):
+        self._operator = operator

utilities/platform-util/platform-util/platform_util/license/constants.py

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2017 Wind River Systems, Inc.
+# Copyright (c) 2017-2020 Wind River Systems, Inc.
 #
 # SPDX-License-Identifier: Apache-2.0
 #
@@ -28,7 +28,9 @@ LICENSE_NAMES = [
     AIO_SX_PRODUCT_CFG
 ]
 
-# License mapping 
+LICENSE_PLUGIN_NAME = 'verify_license'
+
+# License mapping
 LICENSE_MAP = { 
     LICENSE_FEATURE_STD: STD_PRODUCT_CFG,
     LICENSE_FEATURE_AIO: AIO_PRODUCT_CFG,

utilities/platform-util/platform-util/platform_util/license/license.py

@@ -3,33 +3,59 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 #
-import os
-from platform_util.license import exception
+
 import sys
 
+from stevedore import extension
+
+from platform_util.license import constants
+from platform_util.license import exception
+
+
+def suppress_stevedore_errors(manager, entrypoint, exception):
+    """stevedore.ExtensionManager
+    will try to import the entry point defined in the module.
+    License plugins use virtual modules.
+    So ExtensionManager will throw the "Could not load ..."
+    error message, which is expected.
+    Just suppress this error message to avoid cause confusion.
+    """
+    pass
+
 
 def verify_license(*args):
-    """Verify the license file"""
-    if not os.path.isfile(args[0]):
-        raise exception.LicenseNotFound()
+    """Verify license using plugin"""
+
+    license_plugins = extension.ExtensionManager(
+        namespace='platformutil.license_plugins',
+        invoke_on_load=True,
+        invoke_args=(None,),
+        on_load_failure_callback=suppress_stevedore_errors
+    )
+    license_plugins = sorted(license_plugins, key=lambda x: x.name)
+
+    plugin_name = constants.LICENSE_PLUGIN_NAME
+    plugin_obj = None
+    for license_plugin in license_plugins:
+        plugin_obj = license_plugin.obj
+        if plugin_name != license_plugin.name[4:]:
+            break
+    if plugin_obj is not None:
+        plugin_obj.verify_license(*args)
 
 
 def main():
-    # Pass the command arguments to verify_license
+    # Check minimum number of arguments
     if len(sys.argv) < 2:
         print("Usage: verify-license <license file> [<optional_parameter>...]")
         exit(-1)
 
-    arg_list = []
-    for arg in sys.argv:
-        arg_list.append(arg)
-
     # The arguments passed to verify_license from command line
     # will not include sys.argv[0] which is the script name.
     # Only the actual arguments: sys.argv[1] and onward will be passed,
     # meaning license_file followed by optional attributes.
     try:
-        verify_license(*arg_list[1:len(sys.argv)])
+        verify_license(*sys.argv[1:len(sys.argv)])
     except exception.InvalidLicenseType:
         exit(1)
     except exception.LicenseNotFound:
@@ -40,3 +66,7 @@ def main():
         exit(4)
     except exception.InvalidLicense:
         exit(5)
+
+
+if __name__ == '__main__':
+    main()

utilities/platform-util/platform-util/platform_util/license/stxlicense.py

@@ -0,0 +1,22 @@
+# Copyright (c) 2020 Wind River Systems, Inc.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+import os
+
+from platform_util.license import base
+from platform_util.license import exception
+
+
+class StxVerifyLicense(base.BaseLicense):
+    """Class to encapsulate license verification for starlingX """
+
+    def verify_license(self, *args):
+        """Verify the license file"""
+
+        if len(args) < 1:
+            raise Exception("Usage: verify-license <license file> [<optional_parameter>...]")
+
+        if not os.path.isfile(args[0]):
+            raise exception.LicenseNotFound()

utilities/platform-util/platform-util/setup.py

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2017-2018 Wind River Systems, Inc.
+# Copyright (c) 2017-2020 Wind River Systems, Inc.
 #
 # SPDX-License-Identifier: Apache-2.0
 #
@@ -16,5 +16,8 @@ setuptools.setup(
         'console_scripts': [
             'verify-license = platform_util.license.license:main'
         ],
+        'platformutil.license_plugins': [
+            '001_verify_license = platform_util.license.stxlicense:StxVerifyLicense'
+        ],
     }
 )