[openvpn] Added generate_client class method

docs/source/backends/openvpn.rst

@@ -224,3 +224,45 @@ For a list of all the OpenVPN configuration settings, refer to the `OpenVPN 2.3
 
 .. _auth property source code: https://github.com/openwisp/netjsonconfig/blob/master/netjsonconfig/backends/openvpn/schema.py#L79-L89
 .. _cipher property source code: https://github.com/openwisp/netjsonconfig/blob/master/netjsonconfig/backends/openvpn/schema.py#L90-L103
+
+Automatic generation of clients
+-------------------------------
+
+.. automethod:: netjsonconfig.OpenVpn.generate_client
+
+Example:
+
+.. code-block:: python
+
+    from netjsonconfig import OpenVpn
+
+    client_config = OpenVpn.generate_client('vpn1.test.com', {
+        "ca": "ca.pem",
+        "cert": "cert.pem",
+        "dev": "tap0",
+        "dev_type": "tap",
+        "dh": "dh.pem",
+        "key": "key.pem",
+        "mode": "server",
+        "name": "example-vpn",
+        "proto": "udp",
+        "tls_server": True
+    })
+    client = OpenVpn({"openvpn": [client_config]})
+    print(client.render())
+
+Will be rendered as::
+
+    # openvpn config: example-vpn
+
+    ca ca.pem
+    cert cert.pem
+    dev tap0
+    dev-type tap
+    key key.pem
+    mode client
+    nobind
+    proto udp
+    remote vpn1.test.com 1195
+    resolv-retry
+    tls-client

netjsonconfig/backends/base.py

@@ -16,7 +16,7 @@
 
 class BaseBackend(object):
     """
-    TODO: explain
+    Base Backend class
     """
     schema = None
     env_path = 'netjsonconfig.backends.base'

netjsonconfig/backends/openvpn/openvpn.py

@@ -37,3 +37,45 @@ def _generate_contents(self, tar):
             self._add_file(tar=tar,
                            name='{0}.conf'.format(vpn_name),
                            contents=text_contents)
+
+    @classmethod
+    def generate_client(self, host, server):
+        """
+        Generates an OpenVPN client configuration
+        from an existing server configuration.
+
+        :param server: dictionary representing a single OpenVPN server configuration
+        :returns: dictionary representing a single OpenVPN client configuration
+        """
+        # client defaults
+        c = {
+            "mode": "client",
+            "nobind": True,
+            "resolv_retry": True,
+            "tls_client": True
+        }
+        # remote
+        port = server.get('port') or 1195
+        c['remote'] = [{'host': host, 'port': port}]
+        # proto
+        if server.get('proto') == 'tcp-server':
+            c['proto'] = 'tcp-client'
+        else:
+            c['proto'] = 'udp'
+        # tls_client
+        if 'tls_server' not in server or not server['tls_server']:
+            c['tls_client'] = False
+        # ns_cert_type
+        if not server.get('ns_cert_type'):
+            c['ns_cert_type'] = ''
+        elif server.get('ns_cert_type') == 'client':
+            c['ns_cert_type'] = 'server'
+        copy_keys = ['name', 'dev_type', 'dev', 'comp_lzo', 'auth',
+                     'cipher', 'ca', 'cert', 'key', 'mtu_disc', 'mtu_test',
+                     'fragment', 'mssfix', 'keepalive', 'persist_tun', 'mute',
+                     'persist_key', 'script_security', 'user', 'group', 'log',
+                     'mute_replay_warnings', 'secret', 'fast_io', 'verb']
+        for key in copy_keys:
+            if key in server:
+                c[key] = server[key]
+        return c

tests/openvpn/test_backend.py

@@ -380,3 +380,133 @@ def test_generate(self):
 tls-server
 """
         self.assertEqual(contents, expected)
+
+    def test_generate_client_simple(self):
+        client_config = OpenVpn.generate_client('vpn1.test.com', {
+            "ca": "ca.pem",
+            "cert": "cert.pem",
+            "dev": "tap0",
+            "dev_type": "tap",
+            "dh": "dh.pem",
+            "key": "key.pem",
+            "mode": "server",
+            "name": "example-vpn",
+            "proto": "udp",
+        })
+        o = OpenVpn({"openvpn": [client_config]})
+        expected = """# openvpn config: example-vpn
+
+ca ca.pem
+cert cert.pem
+dev tap0
+dev-type tap
+key key.pem
+mode client
+nobind
+proto udp
+remote vpn1.test.com 1195
+resolv-retry
+"""
+        self.assertEqual(o.render(), expected)
+
+    def test_generate_client_tls(self):
+        client_config = OpenVpn.generate_client('vpn2.test.com', {
+            "ca": "ca.pem",
+            "cert": "cert.pem",
+            "dev": "tap0",
+            "dev_type": "tap",
+            "dh": "dh.pem",
+            "key": "key.pem",
+            "mode": "server",
+            "name": "example-vpn",
+            "port": 1196,
+            "proto": "tcp-server",
+            "tls_server": True
+        })
+        o = OpenVpn({"openvpn": [client_config]})
+        expected = """# openvpn config: example-vpn
+
+ca ca.pem
+cert cert.pem
+dev tap0
+dev-type tap
+key key.pem
+mode client
+nobind
+proto tcp-client
+remote vpn2.test.com 1196
+resolv-retry
+tls-client
+"""
+        self.assertEqual(o.render(), expected)
+
+    def test_generate_client_complex(self):
+        client_config = OpenVpn.generate_client('vpn1.test.com', {
+            "ca": "ca.pem",
+            "cert": "cert.pem",
+            "dev": "tap0",
+            "dev_type": "tap",
+            "dh": "dh.pem",
+            "key": "key.pem",
+            "mode": "server",
+            "name": "example-vpn",
+            "proto": "tcp-server",
+            "tls_server": True,
+            "comp_lzo": "yes",
+            "auth": "RSA-SHA1",
+            "cipher": "AES-128-CFB",
+            "engine": "dynamic",
+            "ns_cert_type": "client",
+
+        })
+        o = OpenVpn({"openvpn": [client_config]})
+        expected = """# openvpn config: example-vpn
+
+auth RSA-SHA1
+ca ca.pem
+cert cert.pem
+cipher AES-128-CFB
+comp-lzo yes
+dev tap0
+dev-type tap
+key key.pem
+mode client
+nobind
+ns-cert-type server
+proto tcp-client
+remote vpn1.test.com 1195
+resolv-retry
+tls-client
+"""
+        self.assertEqual(o.render(), expected)
+
+    def test_generate_client_ns_cert_type_empty(self):
+        client_config = OpenVpn.generate_client('vpn1.test.com', {
+            "ca": "ca.pem",
+            "cert": "cert.pem",
+            "dev": "tap0",
+            "dev_type": "tap",
+            "dh": "dh.pem",
+            "key": "key.pem",
+            "mode": "server",
+            "name": "example-vpn",
+            "proto": "udp",
+            "tls_server": True,
+            "ns_cert_type": "",
+        })
+        o = OpenVpn({"openvpn": [client_config]})
+        expected = """# openvpn config: example-vpn
+
+ca ca.pem
+cert cert.pem
+dev tap0
+dev-type tap
+key key.pem
+mode client
+nobind
+proto udp
+remote vpn1.test.com 1195
+resolv-retry
+tls-client
+"""
+        self.assertEqual(o.render(), expected)