Support dynamic gmp protocol selection

CHANGELOG.md

@@ -27,6 +27,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Added a `password only` credential type [PR 133](https://github.com/greenbone/python-gvm/pull/133)
 * Added [type hints](https://docs.python.org/3/library/typing.html) for Gmpv8
   [PR 136](https://github.com/greenbone/python-gvm/pull/136)
+* Added dynamic selection of the Gmp class depending on the GMP version supported
+  by the remote manager daemon
+  [PR 141](https://github.com/greenbone/python-gvm/pull/141)
 
 ### Changed
 * Renamed `create_asset` method to `create_host` and dropped asset_type

docs/api/gmp.rst

@@ -0,0 +1,15 @@
+.. _gmp:
+
+.. avoid TOCtree warning by marking this file als orphan
+
+:orphan:
+
+GMP
+^^^
+.. automodule:: gvm.protocols.gmp
+
+Protocol
+--------
+
+.. autoclass:: Gmp
+    :members:

docs/api/protocols.rst

@@ -12,6 +12,12 @@ Protocols
     gmpv8
     ospv1
 
+Dynamic
+^^^^^^^
+
+To dynamically use the supported GMP version of the manager daemon see
+:mod:`gvm.protocols.gmp` for details.
+
 Latest
 ^^^^^^
 

gvm/protocols/gmp.py

@@ -0,0 +1,105 @@
+# -*- coding: utf-8 -*-
+# Copyright (C) 2019 Greenbone Networks GmbH
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+Module for communication with gvmd
+"""
+from typing import Any, Optional, Callable
+
+from gvm.errors import GvmError
+
+from gvm.protocols.base import GvmProtocol, GvmConnection
+
+from gvm.protocols.gmpv7 import Gmp as Gmpv7
+from gvm.protocols.gmpv8 import Gmp as Gmpv8
+
+from gvm.transforms import EtreeCheckCommandTransform
+
+from gvm.xml import XmlCommand
+
+
+class Gmp(GvmProtocol):
+    """Dynamically select supported GMP protocol of the remote manager daemon.
+
+    Must be used as a `Context Manager
+    <https://docs.python.org/3/reference/datamodel.html#context-managers>`_
+
+    Example:
+
+        .. code-block:: python
+
+            from gvm.protocols.gmp import Gmp
+
+            with Gmp(connection) as gmp:
+                # gmp can be an instance of gvm.protocols.gmpv7.Gmp or
+                # gvm.protocols.gmpv8.Gmp depending on the supported GMP
+                # version of the remote manager daemon
+                resp = gmp.get_tasks()
+
+    Attributes:
+        connection: Connection to use to talk with the remote daemon. See
+            :mod:`gvm.connections` for possible connection types.
+        transform: Optional transform `callable`_ to convert response data.
+            After each request the callable gets passed the plain response data
+            which can be used to check the data and/or conversion into different
+            representations like a xml dom.
+
+            See :mod:`gvm.transforms` for existing transforms.
+
+    .. _callable:
+        https://docs.python.org/3/library/functions.html#callable
+    """
+
+    def __init__(
+        self,
+        connection: GvmConnection,
+        *,
+        transform: Optional[Callable[[str], Any]] = None
+    ):
+        super().__init__(connection, transform=EtreeCheckCommandTransform())
+        self._gmp_transform = transform
+
+    def __enter__(self):
+        self.connect()
+        resp = self._send_xml_command(XmlCommand("get_version"))
+        self.disconnect()
+
+        version_el = resp.find('version')
+        if version_el is None:
+            raise GvmError(
+                'Invalid response from manager daemon while requesting the '
+                'version information.'
+            )
+
+        version = version_el.text
+        major_version = version[0]
+
+        if major_version == '7':
+            gmp_class = Gmpv7
+        elif major_version == '8':
+            gmp_class = Gmpv8
+        else:
+            raise GvmError(
+                'Remote manager daemon uses an unsupported version of GMP.'
+                'The GMP version was {}'.format(major_version)
+            )
+
+        gmp = gmp_class(self._connection, transform=self._gmp_transform)
+        gmp.connect()
+
+        return gmp

tests/protocols/gmp/__init__.py

@@ -0,0 +1,17 @@
+# -*- coding: utf-8 -*-
+# Copyright (C) 2019 Greenbone Networks GmbH
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.

tests/protocols/gmp/test_context_manager.py

@@ -0,0 +1,87 @@
+# -*- coding: utf-8 -*-
+# Copyright (C) 2019 Greenbone Networks GmbH
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import unittest
+
+from tests.protocols import GmpTestCase
+
+from gvm.errors import GvmError
+
+from gvm.protocols.gmp import Gmp
+from gvm.protocols.gmpv7 import Gmp as Gmpv7
+from gvm.protocols.gmpv8 import Gmp as Gmpv8
+
+
+class GmpContextManagerTestCase(GmpTestCase):
+
+    gmp_class = Gmp
+
+    def test_select_gmpv7(self):
+        self.connection.read.return_value(
+            '<get_version_response status="200" status_text="OK">'
+            '<version>7.0</version>'
+            '</get_version_response>'
+        )
+
+        with self.gmp as gmp:
+            self.assertEqual(gmp.get_protocol_version(), "7")
+            self.assertIsInstance(gmp, Gmpv7)
+
+    def test_select_gmpv8(self):
+        self.connection.read.return_value(
+            '<get_version_response status="200" status_text="OK">'
+            '<version>8.0</version>'
+            '</get_version_response>'
+        )
+
+        with self.gmp as gmp:
+            self.assertEqual(gmp.get_protocol_version(), "8")
+            self.assertIsInstance(gmp, Gmpv8)
+
+    def test_unknown_protocol(self):
+        self.connection.read.return_value(
+            '<get_version_response status="200" status_text="OK">'
+            '<version>1.0</version>'
+            '</get_version_response>'
+        )
+
+        with self.assertRaises(GvmError):
+            with self.gmp:
+                pass
+
+    def test_missing_version_in_response(self):
+        self.connection.read.return_value(
+            '<get_version_response status="200" status_text="OK">'
+            '<foo>bar</foo>'
+            '</get_version_response>'
+        )
+
+        with self.assertRaises(GvmError):
+            with self.gmp:
+                pass
+
+    def test_invalid_response(self):
+        self.connection.read.return_value('<get_foo_response/>')
+
+        with self.assertRaises(GvmError):
+            with self.gmp:
+                pass
+
+
+if __name__ == '__main__':
+    unittest.main()