Add dmslave_info textfile collector

dmslave_info.py

@@ -0,0 +1,45 @@
+#!/usr/bin/env python3
+"""
+Script to count the number of lun devices associated with device-mapper
+slaves and expose a summary as Prometheus metrics.
+"""
+
+import os
+import sys
+import argparse
+from prometheus_client import CollectorRegistry, Gauge, write_to_textfile
+
+sysfs = "/sys/devices/"
+
+def main(arguments):
+
+    parser = argparse.ArgumentParser(description="detect lun devices associated with DM",
+                                 epilog=__doc__)
+    parser.add_argument("-f", "--prom-file",
+                        default='/var/lib/prometheus/node-exporter/dmslave_info.prom',
+                        help="Write prometheus metrics to specified file (default: %(default)s)")
+
+    args = parser.parse_args(arguments)
+
+    registry = CollectorRegistry()
+
+    gauge_dm_info = Gauge('node_dmslave_info',
+                          'Devicemapper slave information',
+                          ['dm_device', 'lun_name'],
+                          registry=registry)
+
+    dm = [x for x in os.listdir(sysfs+'virtual/block/') if x.startswith('dm')]
+    for dx in dm:
+        dm_sd =  os.listdir(sysfs+'virtual/block/'+dx+'/slaves/')
+        lun_count = len(dm_sd)
+        if lun_count:
+            for i in range(lun_count):
+                gauge_dm_info.labels(dx, dm_sd[i]).set(lun_count)
+        else:
+                gauge_dm_info.labels(dx, " ").set(0)
+
+    write_to_textfile(str(args.prom_file), registry)
+
+if __name__ == "__main__":
+    main(sys.argv[1:]) # pragma: no cover
+