T775: Add service config-sync between 2 routers

Service config-sync allows synchronizing a section of
the configuration.
As PoC allow only nat, nat66 and firewall sections

Rertreive the configuration for a section from self node and
send this configuration to the section of the 'secondary' node.

This feature adds a symlink from helper 'vyos_config_sync.py'
to '/config/scripts/commit/post-hooks.d' and config that is
located in '/run/config_sync_conf.conf'
It will synchronyze the config only if the setcion
was changed.

set service config-sync secondary address 192.0.2.11
set service config-sync secondary key xxx
set service config-sync section nat
set service config-sync section nat66
set service config-sync section firewall
set service config-sync mode load

1 files changed, 111 insertions, 0 deletions

diff --git a/src/conf_mode/service_config_sync.py b/src/conf_mode/service_config_sync.py
new file mode 100755
index 000000000..5cde735a1
--- /dev/null
+++ b/src/conf_mode/service_config_sync.py
@@ -0,0 +1,111 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2023 VyOS maintainers and contributors
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 or later as
+# published by the Free Software Foundation.
+#
+# 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 os
+import json
+from pathlib import Path
+
+from vyos.config import Config
+from vyos.configdict import dict_merge
+from vyos.xml import defaults
+from vyos import ConfigError
+from vyos import airbag
+
+airbag.enable()
+
+
+service_conf = Path(f'/run/config_sync_conf.conf')
+post_commit_dir = '/run/scripts/commit/post-hooks.d'
+post_commit_file_src = '/usr/libexec/vyos/vyos_config_sync.py'
+post_commit_file = f'{post_commit_dir}/vyos_config_sync'
+
+
+def get_config(config=None):
+    if config:
+        conf = config
+    else:
+        conf = Config()
+
+    base = ['service', 'config-sync']
+    if not conf.exists(base):
+        return None
+    config = conf.get_config_dict(base,
+                                  get_first_key=True,
+                                  no_tag_node_value_mangle=True)
+
+    default_values = defaults(base)
+    config = dict_merge(default_values, config)
+
+    return config
+
+
+def verify(config):
+    # bail out early - looks like removal from running config
+    if not config:
+        return None
+
+    if 'mode' not in config:
+        raise ConfigError(f'config-sync mode is mandatory!')
+
+    for option in ['secondary', 'section']:
+        if option not in config:
+            raise ConfigError(f"config-sync '{option}' is not configured!")
+
+    if 'address' not in config['secondary']:
+        raise ConfigError(f'secondary address is mandatory!')
+    if 'key' not in config['secondary']:
+        raise ConfigError(f'secondary key is mandatory!')
+
+
+def generate(config):
+    if not config:
+
+        if os.path.exists(post_commit_file):
+            os.unlink(post_commit_file)
+
+        if service_conf.exists():
+            service_conf.unlink()
+
+        return None
+
+    # Write configuration file
+    conf_json = json.dumps(config, indent=4)
+    service_conf.write_text(conf_json)
+
+    # Create post commit dir
+    if not os.path.isdir(post_commit_dir):
+        os.makedirs(post_commit_dir)
+
+    # Symlink from helpers to post-commit
+    if not os.path.exists(post_commit_file):
+        os.symlink(post_commit_file_src, post_commit_file)
+
+    return None
+
+
+def apply(config):
+    return None
+
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)