fix: scaling: round bandwidth filtered

because Torflow does it.

docs/source/torflow_aggr.rst

@@ -203,6 +203,18 @@ From Torflow's `README.spec.txt`_ (section 1.6)::
 In the code, `SQLSupport.py`_, ``strm_bw`` is ``sbw`` and
 ``filt_bw`` is ``filt_sbws``::
 
+      for s in rs.router.streams:
+        if isinstance(s, ClosedStream):
+          tot_bytes += s.tot_bytes()
+          tot_duration += s.end_time - s.start_time
+          tot_bw += s.bandwidth()
+          s_cnt += 1
+      # FIXME: Hrmm.. do we want to do weighted avg or pure avg here?
+      # If files are all the same size, it shouldn't matter..
+      if s_cnt > 0:
+        rs.sbw = tot_bw/s_cnt
+      else: rs.sbw = None
+
     for rs in RouterStats.query.filter(stats_clause).\
           options(eagerload_all('router.streams.circuit.routers')).all():
       tot_sbw = 0
@@ -224,6 +236,19 @@ In the code, `SQLSupport.py`_, ``strm_bw`` is ``sbw`` and
     if sbw_cnt: rs.filt_sbw = tot_sbw/sbw_cnt
     else: rs.filt_sbw = None
 
+When it is written to the file, it seem to write "None" string when
+``filt_sbw`` or ``strm_bw`` are None. That would give an exception when
+calculating the network average. So it never happen?::
+
+    def cvt(a,b,c=1):
+      if type(a) == float: return int(round(a/c,b))
+      elif type(a) == int: return a
+      elif type(a) == type(None): return "None"
+      else: return type(a)
+
+    f.write(" strm_bw="+str(cvt(s.sbw,0)))
+    f.write(" filt_bw="+str(cvt(s.filt_sbw,0)))
+
 This is also expressed in pseudocode in the `bandwidth file spec`_, section B.4
 step 1.
 

sbws/lib/scaling.py

@@ -16,8 +16,10 @@ def bw_filt(bw_measurements):
     """
     mu = 1
     if bw_measurements:
-        mu = mean(bw_measurements)
+        # Torflow is rounding to an integer, so is `bw_mean_from_results` in
+        # `v3bwfile.py`
+        mu = round(mean(bw_measurements))
     bws_gte_mean = list(filter(lambda bw: bw >= mu, bw_measurements))
     if bws_gte_mean:
-        return mean(bws_gte_mean)
+        return round(mean(bws_gte_mean))
     return 1

tests/unit/lib/test_scaling.py

 """Unit tests for scaling.py."""
+from statistics import mean
 
 from sbws.lib import scaling
 
@@ -10,4 +11,30 @@ def test_bw_filt():
     ]
     fb = scaling.bw_filt(bw_measurements)
     # This is greater than the mean, that is 61422.73714139576
-    assert fb == 83505.81986994506
+    assert fb == 83506
+
+    # When there are no measurements what can not be the case for successful
+    # results.
+    bw_measurements = []
+    assert 1 == scaling.bw_filt(bw_measurements)
+
+    bw_measurements = [1, 0]
+    # Because rounded to int
+    assert 0 == round(mean(bw_measurements))
+    # So the filtered bw will be also 0
+    assert 0 == scaling.bw_filt(bw_measurements)
+
+    bw_measurements = [1, 2, 3]
+    # Because rounded to int
+    assert 2 == round(mean(bw_measurements))
+    assert 2 == scaling.bw_filt(bw_measurements)
+
+    bw_measurements = [10, 0]
+    assert 5 == round(mean(bw_measurements))
+    # Because the value 10 is bigger than the mean
+    assert 10 == scaling.bw_filt(bw_measurements)
+
+    bw_measurements = [0, 10, 20]
+    assert 10 == round(mean(bw_measurements))
+    # Because 10 and 20 are bigger or equal than the mean
+    assert 15 == scaling.bw_filt(bw_measurements)