NgTech-LTD/gns3-server
2
0
Fork 0
mirror of https://github.com/GNS3/gns3-server.git synced 2026-08-27 12:30:13 +03:00
Code Issues Packages Projects Releases Wiki Activity

feat: add config read-modify-write update and harden file watcher

Browse Source 
Config.update_config() applies submitted options to the main
configuration file via configparser read-modify-write: unknown
options are preserved, null removes an option, the merged view
of all files is validated as ServerConfig before anything is
written (a bad file would kill the FileWatcher polling loop),
and the write is atomic (.tmp + os.replace, mode 0600). Options
whose effective value is owned by a later configuration file
raise ConfigConflictError instead of writing a no-op. The
reload logic is factored into reload_and_notify() and the file
watcher callback is exception-guarded so polling never dies.
This commit is contained in:
YueGuobin 2026-08-23 18:54:23 +08:00
parent d3ceb453a6
commit 7d3cbf1023
No known key found for this signature in database
5 changed files with 282 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

122
gns3server/config.py
View File

@ -24,6 +24,7 @@ import shutil
import secrets
import configparser
from enum import Enum
from pydantic import ValidationError
from .schemas import ServerConfig
from .version import __version_info__
@ -34,6 +35,19 @@ import logging
log = logging.getLogger(__name__)
class ConfigConflictError(Exception):
"""
Raised when a configuration option is set in a configuration file that
takes precedence over the main configuration file.
"""
# List options written back to the configuration file as semicolon-separated
# values; every other list option is comma-separated (must match the field
# validators splitting them in gns3server.schemas.config).
LIST_OPTION_SEPARATORS = {"additional_images_paths": ";"}
class Config:
"""
Configuration file management using configparser.
@ -199,6 +213,13 @@ class Config:
"""
log.info(f"'{file_path}' has been updated, reloading the config...")
self.reload_and_notify()
def reload_and_notify(self):
"""
Reload the configuration files and notify registered listeners.
"""
self.read_config()
for callback in self._watch_callback:
callback()
@ -210,6 +231,107 @@ class Config:
self.read_config()
@staticmethod
def _stringify_option(option: str, value) -> str:
"""
Serialize a settings value to its INI string representation.
"""
if isinstance(value, bool):
return str(value)
if isinstance(value, Enum):
return str(value.value)
if isinstance(value, list):
return LIST_OPTION_SEPARATORS.get(option, ",").join(value)
return str(value)
def update_config(self, changes: dict) -> list:
"""
Apply setting changes to the main configuration file (read-modify-write).
Only the submitted options are set or removed, preserving any unknown
options present in the file. The merged configuration is validated
before anything is written to disk, so an invalid change leaves the
file untouched (a file that fails validation would permanently kill
the FileWatcher polling loop when it gets reloaded).
:param changes: mapping of section name to {option: value}; a value of
None removes the option from the file, restoring its default
:returns: sorted list of changed options as "Section.option" strings
:raises pydantic.ValidationError: the merged settings are invalid
:raises ConfigConflictError: an option is set in a configuration file
that takes precedence over the main configuration file
:raises OSError: the configuration file could not be written
"""
if not changes:
return []
main_config_file = self._main_config_file
existing_files = [file for file in self._files if os.path.isfile(file)]
# per-file parsers to find which file wins for an option
# (later files take precedence, mirroring read_config)
per_file_parsers = []
for file in existing_files:
parser = configparser.ConfigParser(interpolation=None)
parser.read(file, encoding="utf-8")
per_file_parsers.append(parser)
# view of what gets written: the main configuration file only
write_parser = configparser.ConfigParser(interpolation=None)
if os.path.isfile(main_config_file):
write_parser.read(main_config_file, encoding="utf-8")
# view of what the server will load: all configuration files merged
merged_parser = configparser.ConfigParser(interpolation=None)
merged_parser.read(existing_files, encoding="utf-8")
changed = []
for section, options in changes.items():
for option, value in options.items():
winner = None
for file, parser in zip(reversed(existing_files), reversed(per_file_parsers)):
if parser.has_option(section, option):
winner = file
break
if winner is not None and winner != main_config_file:
raise ConfigConflictError(
f"'{section}.{option}' is set in '{winner}' which takes precedence "
f"over the main configuration file '{main_config_file}'"
)
if value is None:
# explicit null: remove the option to restore its default
if write_parser.has_option(section, option):
write_parser.remove_option(section, option)
if merged_parser.has_option(section, option):
merged_parser.remove_option(section, option)
else:
option_value = self._stringify_option(option, value)
if not write_parser.has_section(section):
write_parser.add_section(section)
write_parser.set(section, option, option_value)
if not merged_parser.has_section(section):
merged_parser.add_section(section)
merged_parser.set(section, option, option_value)
changed.append(f"{section}.{option}")
# validate the merged settings before touching the file on disk
ServerConfig(**merged_parser._sections)
directory_name = os.path.dirname(main_config_file)
if directory_name:
os.makedirs(directory_name, exist_ok=True)
tmp_file = main_config_file + ".tmp"
fd = os.open(tmp_file, os.O_WRONLY | os.O_CREAT | os.O_TRUNC, 0o600)
with os.fdopen(fd, "w", encoding="utf-8") as f:
write_parser.write(f)
os.replace(tmp_file, main_config_file)
self.reload_and_notify()
return sorted(changed)
def get_config_files(self):
"""
Return the config files in use.

20
gns3server/schemas/config.py
View File

@ -202,28 +202,36 @@ class ServerSettings(BaseModel):
def split_mcp_allowed_hosts(cls, v):
if v and isinstance(v, str):
return v.split(",")
return list()
if not v:
return list()
return v
@field_validator("mcp_allowed_origins", mode="before")
@classmethod
def split_mcp_allowed_origins(cls, v):
if v and isinstance(v, str):
return v.split(",")
return list()
if not v:
return list()
return v
@field_validator("additional_images_paths", mode="before")
@classmethod
def split_additional_images_paths(cls, v):
if v:
if v and isinstance(v, str):
return v.split(";")
return list()
if not v:
return list()
return v
@field_validator("allowed_interfaces", mode="before")
@classmethod
def split_allowed_interfaces(cls, v):
if v:
if v and isinstance(v, str):
return v.split(",")
return list()
if not v:
return list()
return v
@model_validator(mode="after")
def check_console_port_range(self) -> "ServerSettings":

11
gns3server/utils/file_watcher.py
View File

@ -19,6 +19,10 @@ import zlib
import asyncio
import os
import logging
log = logging.getLogger(__name__)
class FileWatcher:
"""
@ -98,7 +102,12 @@ class FileWatcher:
except OSError:
self._hashed[path] = None
if changed:
self._callback(path)
try:
self._callback(path)
except Exception:
# never let a callback exception kill the polling loop
# (the re-schedule below must always run)
log.exception(f"Error in file watcher callback for '{path}'")
asyncio.get_event_loop().call_later(self._delay, self._check_config_file_change)
@property

119
tests/test_config.py
View File

@ -17,9 +17,11 @@
import configparser
import os
import pytest
from gns3server.config import Config
from gns3server.config import ConfigConflictError
from gns3server.config import ServerConfig
from pydantic import ValidationError
@ -158,3 +160,120 @@ def test_vmware_settings(settings: dict, exception_expected: bool):
ServerConfig(**vmware_settings)
else:
ServerConfig(**vmware_settings)
def test_update_config_writes_ini_types(tmpdir):
path = str(tmpdir / "server.conf")
with open(path, "w+") as f:
f.write("# a comment\n[Server]\nhost = 127.0.0.1\nfrobnicate = 42\n")
config = Config(files=[path])
changed = config.update_config({
"Server": {
"port": 3081,
"report_errors": False,
"allowed_interfaces": ["eth0", "eth1"],
"default_symbol_theme": "Classic",
"additional_images_paths": ["/path/to/dir1", "/path/to/dir2"],
}
})
parsed = configparser.ConfigParser()
parsed.read(path)
assert parsed["Server"]["port"] == "3081"
assert parsed["Server"]["report_errors"] == "False"
assert parsed["Server"]["allowed_interfaces"] == "eth0,eth1"
assert parsed["Server"]["default_symbol_theme"] == "Classic"
assert parsed["Server"]["additional_images_paths"] == "/path/to/dir1;/path/to/dir2"
# options not submitted are left untouched, including unknown ones
assert parsed["Server"]["host"] == "127.0.0.1"
assert parsed["Server"]["frobnicate"] == "42"
# in-memory settings have been reloaded
assert config.settings.Server.port == 3081
assert config.settings.Server.report_errors is False
assert config.settings.Server.allowed_interfaces == ["eth0", "eth1"]
assert changed == [
"Server.additional_images_paths",
"Server.allowed_interfaces",
"Server.default_symbol_theme",
"Server.port",
"Server.report_errors",
]
def test_update_config_null_removes_option(tmpdir):
path = write_config(tmpdir, {"Server": {"host": "127.0.0.1"}})
config = Config(files=[path])
config.update_config({"Server": {"host": None}})
parsed = configparser.ConfigParser()
parsed.read(path)
assert not parsed.has_option("Server", "host")
assert config.settings.Server.host == "0.0.0.0" # default restored
def test_update_config_validation_failure_leaves_file_unchanged(tmpdir):
path = write_config(tmpdir, {"Server": {"console_start_port_range": "5000"}})
config = Config(files=[path])
with open(path) as f:
file_content_before = f.read()
# cross-field violation (console_end_port_range must be > console_start_port_range)
with pytest.raises(ValidationError):
config.update_config({"Server": {"console_start_port_range": 10000, "console_end_port_range": 5000}})
with open(path) as f:
assert f.read() == file_content_before
def test_update_config_conflict(tmpdir):
main_path = write_config(tmpdir, {"Server": {"host": "127.0.0.1"}})
override_path = str(tmpdir / "override.conf")
with open(override_path, "w+") as f:
f.write("[Server]\nhost = 10.0.0.1\n")
config = Config(files=[main_path, override_path])
assert config.settings.Server.host == "10.0.0.1" # later file takes precedence
with pytest.raises(ConfigConflictError):
config.update_config({"Server": {"host": "192.168.1.1"}})
with pytest.raises(ConfigConflictError):
config.update_config({"Server": {"host": None}})
with open(main_path) as f:
assert "host = 127.0.0.1" in f.read() # main file untouched
def test_update_config_creates_missing_main_file(tmpdir):
path = write_config(tmpdir, {"Server": {"host": "127.0.0.1"}})
config = Config(files=[path])
os.remove(path)
config.update_config({"Server": {"port": 3081}})
parsed = configparser.ConfigParser()
parsed.read(path)
assert parsed["Server"]["port"] == "3081"
assert not parsed.has_option("Server", "host") # removed file means defaults
def test_reload_and_notify(tmpdir):
path = write_config(tmpdir, {"Server": {"host": "127.0.0.1"}})
config = Config(files=[path])
notified = []
config.listen_for_config_changes(lambda: notified.append(True))
write_config(tmpdir, {"Server": {"host": "192.168.1.2"}})
config.reload_and_notify()
assert config.settings.Server.host == "192.168.1.2"
assert notified == [True]

17
tests/utils/test_file_watcher.py
View File

@ -66,3 +66,20 @@ async def test_file_watcher_list(tmpdir, strategy):
file2.write("b")
await asyncio.sleep(0.5)
callback.assert_called_with(str(file2))
@pytest.mark.asyncio
async def test_file_watcher_callback_exception_does_not_stop_polling(tmpdir):
file = tmpdir / "test"
file.write("a")
callback = MagicMock(side_effect=ValueError("callback error"))
FileWatcher(file, callback, delay=0.1)
await asyncio.sleep(0.5)
assert callback.call_count == 0
file.write("b")
await asyncio.sleep(0.5)
assert callback.call_count == 1 # raised, but must not kill the polling loop
file.write("c")
await asyncio.sleep(0.5)
assert callback.call_count == 2 # polling survived the exception