configd: T2582: add config daemon and supporting files

1 files changed, 224 insertions, 0 deletions

diff --git a/src/services/vyos-configd b/src/services/vyos-configd
new file mode 100755
index 000000000..75f84d3df
--- /dev/null
+++ b/src/services/vyos-configd
@@ -0,0 +1,224 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2020 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 sys
+import grp
+import re
+import json
+import logging
+import signal
+import importlib.util
+import zmq
+
+from vyos.defaults import directories
+from vyos.configsource import ConfigSourceString
+from vyos.config import Config
+from vyos import ConfigError
+
+CFG_GROUP = 'vyattacfg'
+
+debug = True
+
+logger = logging.getLogger(__name__)
+logs_handler = logging.StreamHandler()
+logger.addHandler(logs_handler)
+
+if debug:
+    logger.setLevel(logging.DEBUG)
+else:
+    logger.setLevel(logging.INFO)
+
+SOCKET_PATH = "ipc:///run/vyos-configd.sock"
+
+# Response error codes
+R_SUCCESS = 1
+R_ERROR_COMMIT = 2
+R_ERROR_DAEMON = 4
+R_PASS = 8
+
+vyos_conf_scripts_dir = directories['conf_mode']
+configd_include_file = os.path.join(directories['data'], 'configd-include.json')
+configd_env_set_file = os.path.join(directories['data'], 'vyos-configd-env-set')
+configd_env_unset_file = os.path.join(directories['data'], 'vyos-configd-env-unset')
+# sourced on entering config session
+configd_env_file = '/etc/default/vyos-configd-env'
+
+active_string = ''
+session_string = ''
+
+def key_name_from_file_name(f):
+    return os.path.splitext(f)[0]
+
+def module_name_from_key(k):
+    return k.replace('-', '_')
+
+def path_from_file_name(f):
+    return os.path.join(vyos_conf_scripts_dir, f)
+
+# opt-in to be run by daemon
+with open(configd_include_file) as f:
+    try:
+        include = json.load(f)
+    except OSError as e:
+        logger.critical(f"configd include file error: {e}")
+        sys.exit(1)
+    except json.JSONDecodeError as e:
+        logger.critical(f"JSON load error: {e}")
+        sys.exit(1)
+
+# import conf_mode scripts
+(_, _, filenames) = next(iter(os.walk(vyos_conf_scripts_dir)))
+filenames.sort()
+
+load_filenames = [f for f in filenames if f in include]
+imports = [key_name_from_file_name(f) for f in load_filenames]
+module_names = [module_name_from_key(k) for k in imports]
+paths = [path_from_file_name(f) for f in load_filenames]
+to_load = list(zip(module_names, paths))
+
+modules = []
+
+for x in to_load:
+    spec = importlib.util.spec_from_file_location(x[0], x[1])
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    modules.append(module)
+
+conf_mode_scripts = dict(zip(imports, modules))
+
+exclude_set = {key_name_from_file_name(f) for f in filenames if f not in include}
+include_set = {key_name_from_file_name(f) for f in filenames if f in include}
+
+
+def run_script(script, config) -> int:
+    config.set_level([])
+    try:
+        c = script.get_config(config)
+        script.verify(c)
+        script.generate(c)
+        script.apply(c)
+    except ConfigError as e:
+        logger.critical(e)
+        return R_ERROR_COMMIT
+    except Exception:
+        return R_ERROR_DAEMON
+
+    return R_SUCCESS
+
+def initialization(socket):
+    # Reset config strings:
+    active_string = ''
+    session_string = ''
+    # zmq synchronous for ipc from single client:
+    active_string = socket.recv().decode()
+    resp = "active"
+    socket.send(resp.encode())
+    session_string = socket.recv().decode()
+    resp = "session"
+    socket.send(resp.encode())
+
+    configsource = ConfigSourceString(running_config_text=active_string,
+                                      session_config_text=session_string)
+
+    config = Config(config_source=configsource)
+
+    return config
+
+def process_node_data(config, data) -> int:
+    if not config:
+        logger.critical(f"Empty config")
+        return R_ERROR_DAEMON
+
+    script_name = None
+
+    res = re.match(r'^.+\/([^/].+).py(VYOS_TAGNODE_VALUE=.+)?', data)
+    if res.group(1):
+        script_name = res.group(1)
+    if res.group(2):
+        env = res.group(2).split('=')
+        os.environ[env[0]] = env[1]
+
+    if not script_name:
+        logger.critical(f"Missing script_name")
+        return R_ERROR_DAEMON
+
+    if script_name in exclude_set:
+        return R_PASS
+
+    result = run_script(conf_mode_scripts[script_name], config)
+
+    return result
+
+def remove_if_file(f: str):
+    try:
+        os.remove(f)
+    except FileNotFoundError:
+        pass
+    except OSError:
+        raise
+
+def shutdown():
+    remove_if_file(configd_env_file)
+    os.symlink(configd_env_unset_file, configd_env_file)
+    sys.exit(0)
+
+if __name__ == '__main__':
+    context = zmq.Context()
+    socket = context.socket(zmq.REP)
+
+    # Set the right permissions on the socket, then change it back
+    o_mask = os.umask(0)
+    socket.bind(SOCKET_PATH)
+    os.umask(o_mask)
+
+    cfg_group = grp.getgrnam(CFG_GROUP)
+    os.setgid(cfg_group.gr_gid)
+
+    os.environ['SUDO_USER'] = 'vyos'
+    os.environ['SUDO_GID'] = str(cfg_group.gr_gid)
+
+    def sig_handler(signum, frame):
+        shutdown()
+
+    signal.signal(signal.SIGTERM, sig_handler)
+    signal.signal(signal.SIGINT, sig_handler)
+
+    # Define the vyshim environment variable
+    remove_if_file(configd_env_file)
+    os.symlink(configd_env_set_file, configd_env_file)
+
+    config = None
+
+    while True:
+        #  Wait for next request from client
+        msg = socket.recv().decode()
+        logger.debug(f"Received message: {msg}")
+        message = json.loads(msg)
+
+        if message["type"] == "init":
+            resp = "init"
+            socket.send(resp.encode())
+            config = initialization(socket)
+        elif message["type"] == "node":
+            res = process_node_data(config, message["data"])
+            response = res.to_bytes(1, byteorder=sys.byteorder)
+            logger.debug(f"Sending response {res}")
+            socket.send(response)
+        else:
+            logger.critical(f"Unexpected message: {message}")