Add a textfile helper for NTPd.

Parse the output of `ntpq -np` to provide metrics from a local NTP
daemon.

text_collector_examples/ntpd_metrics.py

@@ -0,0 +1,113 @@
+#!/usr/bin/env python3
+#
+# Description: Extract NTPd metrics from ntpq -np.
+# Author: Ben Kochie <superq@gmail.com>
+
+import re
+import subprocess
+import sys
+
+# NTP peers status, with no DNS lookups.
+ntpq_cmd = ['ntpq', '-np']
+
+# Regex to match all of the fields in the output of ntpq -np
+metrics_fields = [
+    '^(?P<status>.)(?P<remote>[\w\.]+)',
+    '(?P<refid>[\w\.]+)',
+    '(?P<stratum>\d+)',
+    '(?P<type>\w)',
+    '(?P<when>\d+)',
+    '(?P<poll>\d+)',
+    '(?P<reach>\d+)',
+    '(?P<delay>\d+\.\d+)',
+    '(?P<offset>-?\d+\.\d+)',
+    '(?P<jitter>\d+\.\d+)',
+]
+metrics_re = '\s+'.join(metrics_fields)
+
+# Remote types
+# http://support.ntp.org/bin/view/Support/TroubleshootingNTP
+remote_types = {
+    'l': 'local',
+    'u': 'unicast',
+    'm': 'multicast',
+    'b': 'broadcast',
+    '-': 'netaddr',
+}
+
+# Status codes:
+# http://www.eecis.udel.edu/~mills/ntp/html/decode.html#peer
+status_types = {
+    ' ': 0,
+    'x': 1,
+    '.': 2,
+    '-': 3,
+    '+': 4,
+    '#': 5,
+    '*': 6,
+    'o': 7,
+}
+
+
+# Run the ntpq command.
+def get_ntpq():
+    try:
+        ntpq = subprocess.check_output(ntpq_cmd, stderr=subprocess.DEVNULL)
+    except subprocess.CalledProcessError as e:
+        return None
+    return ntpq.decode()
+
+
+# Print metrics in Prometheus format.
+def print_prometheus(metric, values):
+    print("# HELP ntpd_%s NTPd metric for %s" % (metric, metric))
+    print("# TYPE ntpd_%s gauge" % (metric))
+    for labels in values:
+        print("ntpd_%s{%s} %f" % (metric, labels, values[labels]))
+
+
+# Parse raw ntpq lines.
+def parse_line(line):
+    if re.match('\s+remote\s+refid', line):
+        return None
+    if re.match('=+', line):
+        return None
+    if re.match('.+\.(LOCL|POOL)\.', line):
+        return None
+    if re.match('^$', line):
+        return None
+    return re.match(metrics_re, line)
+
+
+# Main function
+def main(argv):
+    ntpq = get_ntpq()
+    peer_status_metrics = {}
+    delay_metrics = {}
+    offset_metrics = {}
+    jitter_metrics = {}
+    for line in ntpq.split('\n'):
+        metric_match = parse_line(line)
+        if metric_match is None:
+            continue
+        remote = metric_match.group('remote')
+        refid = metric_match.group('refid')
+        stratum = metric_match.group('stratum')
+        remote_type = remote_types[metric_match.group('type')]
+        common_labels = "remote=\"%s\",reference=\"%s\"" % (remote, refid)
+        peer_labels = "%s,stratum=\"%s\",type=\"%s\"" % (common_labels, stratum, remote_type)
+
+        peer_status_metrics[peer_labels] = float(status_types[metric_match.group('status')])
+        delay_metrics[common_labels] = float(metric_match.group('delay'))
+        offset_metrics[common_labels] = float(metric_match.group('offset'))
+        jitter_metrics[common_labels] = float(metric_match.group('jitter'))
+ 
+    print_prometheus('peer_status', peer_status_metrics)
+    print_prometheus('delay_milliseconds', delay_metrics)
+    print_prometheus('offset_milliseconds', offset_metrics)
+    print_prometheus('jitter_milliseconds', jitter_metrics)
+
+
+# Go go go!
+if __name__ == "__main__":
+     main(sys.argv[1:])