T973: add basic node_exporter implementation

1 files changed, 104 insertions, 0 deletions

diff --git a/src/conf_mode/service_monitoring_node-exporter.py b/src/conf_mode/service_monitoring_node-exporter.py
new file mode 100755
index 000000000..e8d7c15b4
--- /dev/null
+++ b/src/conf_mode/service_monitoring_node-exporter.py
@@ -0,0 +1,104 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2021-2024 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
+
+from sys import exit
+
+from vyos.config import Config
+from vyos.configdict import is_node_changed
+from vyos.configverify import verify_vrf
+from vyos.template import render
+from vyos.utils.process import call
+from vyos import ConfigError
+from vyos import airbag
+
+
+airbag.enable()
+
+service_file = '/etc/systemd/system/node_exporter.service'
+systemd_service = 'node_exporter.service'
+
+
+def get_config(config=None):
+    if config:
+        conf = config
+    else:
+        conf = Config()
+    base = ['service', 'monitoring', 'node-exporter']
+    if not conf.exists(base):
+        return None
+
+    config_data = conf.get_config_dict(
+        base, key_mangling=('-', '_'), get_first_key=True
+    )
+    config_data = conf.merge_defaults(config_data, recursive=True)
+
+    tmp = is_node_changed(conf, base + ['vrf'])
+    if tmp:
+        config_data.update({'restart_required': {}})
+
+    return config_data
+
+
+def verify(config_data):
+    # bail out early - looks like removal from running config
+    if not config_data:
+        return None
+
+    verify_vrf(config_data)
+    return None
+
+
+def generate(config_data):
+    if not config_data:
+        # Delete systemd files
+        if os.path.isfile(service_file):
+            os.unlink(service_file)
+        return None
+
+    # Render node_exporter service_file
+    render(service_file, 'node_exporter/node_exporter.service.j2', config_data)
+    return None
+
+
+def apply(config_data):
+    # Reload systemd manager configuration
+    call('systemctl daemon-reload')
+    if not config_data:
+        call(f'systemctl stop {systemd_service}')
+        return
+
+    # we need to restart the service if e.g. the VRF name changed
+    systemd_action = 'reload-or-restart'
+    if 'restart_required' in config_data:
+        systemd_action = 'restart'
+
+    call(f'systemctl {systemd_action} {systemd_service}')
+
+    # Telegraf include custom rsyslog config changes
+    call('systemctl reload-or-restart rsyslog')
+
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)