--- a/lib/export_to_influxdb.py	Thu Apr 04 02:22:04 2019 -0700
+++ b/lib/export_to_influxdb.py	Sun Apr 07 03:56:17 2019 -0700
@@ -1,21 +1,76 @@
-import time, logging
+import time, logging, math, os, sys, socket
 from influxdb import InfluxDBClient
 from rdflib import Namespace
+from twisted.internet import task
 
 log = logging.getLogger()
 ROOM = Namespace('http://projects.bigasterisk.com/room/')
 
+class RetentionPolicies(object):
+    def __init__(self, influx):
+        self.influx = influx
+        self.createdPolicies = set() # days
+
+    def getCreatedPolicy(self, days):
+        name = 'ret_%d_day' % days
+        if days not in self.createdPolicies:
+            self.influx.create_retention_policy(name,
+                                                duration='%dd' % days,
+                                                replication='1')
+            self.createdPolicies.add(days)
+        return name
+        
 class InfluxExporter(object):
     def __init__(self, configGraph, influxHost='bang6'):
         self.graph = configGraph
         self.influx = InfluxDBClient(influxHost, 9060, 'root', 'root', 'main')
+        self.retentionPolicies = RetentionPolicies(self.influx)
+        self.lastSent = {}
         self.lastExport = 0
-        self.lastSent = {}  # (subj, measurementName, tags) : (time, value)
 
         self.measurements = {} # (subj, predicate) : measurement
         for s, m in self.graph.subject_objects(ROOM['influxMeasurement']):
             self.measurements[(s, self.graph.value(m, ROOM['predicate']))] = m
-        
+
+    def exportStats(self, stats, paths, period_secs=10, retain_days=7):
+        # graphite version of this in scales/graphite.py
+        base = ['stats', os.path.basename(sys.argv[0]).split('.py')[0]]
+        tags  = {'host': socket.gethostname()}
+        def send():
+            now = int(time.time())
+            points = []
+            def getVal(path):
+                x = stats
+                comps = path.split('.')[1:]
+                for comp in comps:
+                    x2 = x
+                    x = getattr(x, comp, None)
+                    if x is None:
+                        x = x2[comp]
+                        if x is None:
+                            print("no path %s" % path)
+                            return
+                if math.isnan(x):
+                    return
+                points.append({
+                    'measurement': '.'.join(base + comps[:-1]),
+                    "tags": tags,
+                    "fields": {comps[-1]: x},
+                    "time": now
+                })
+            for path in paths:
+                getVal(path)
+            if points:
+                self.influx.write_points(
+                    points, time_precision='s',
+                    retention_policy=self.retentionPolicies.getCreatedPolicy(days=retain_days))
+                if self.lastExport == 0:
+                    log.info('writing stats to %r', points)
+                self.lastExport = now
+                #print('send %r' % points)
+            
+        task.LoopingCall(send).start(period_secs, now=False)
+            
     def exportToInflux(self, currentStatements):
         graph = self.graph
         now = int(time.time())