graph: Align time-series before grouping them.

Previously, an error was returned if the inputs where not perfectly aligned.

diff --git a/graph/graph.go b/graph/graph.go
index 17de57d8e48552d4672d6883e064b68e9c476041..76c6eaf18f85a4a9f22b7f8af510462e33be584c 100644 (file)
--- a/graph/graph.go
+++ b/graph/graph.go
@@ -112,24 +112,63 @@ func (p *pl) addTimeseries(c *client.Client, metric Metric, verbose bool) error
        return nil
 }
 
-// sum is an aggregation function that adds ts2 to ts1.
-func sum(ts1, ts2 *sysdb.Timeseries) error {
-       if !ts1.Start.Equal(ts1.Start) || !ts1.End.Equal(ts2.End) {
-               return fmt.Errorf("Timeseries cover different ranges: [%s, %s] != [%s, %s]",
-                       ts1.Start, ts1.End, ts2.Start, ts2.End)
-       }
+// align aligns two timeseries such that start and end times and the step
+// sizes match.
+func align(ts1, ts2 *sysdb.Timeseries) error {
        if len(ts1.Data) != len(ts2.Data) {
-               return fmt.Errorf("Incompatible time-series: %v != %v", ts1.Data, ts2.Data)
+               return fmt.Errorf("mismatching data sources: %v != %v", ts1.Data, ts2.Data)
+       }
+
+       start := time.Time(ts1.Start)
+       if t := time.Time(ts2.Start); t.After(start) {
+               start = t
+       }
+       end := time.Time(ts1.End)
+       if t := time.Time(ts2.End); t.Before(end) {
+               end = t
+       }
+       if end.Before(start) {
+               return fmt.Errorf("non-overlapping ranges: [%v, %v] <-> [%v, %v]",
+                       ts1.Start, ts1.End, ts2.Start, ts2.End)
        }
 
+       range1 := time.Time(ts1.End).Sub(time.Time(ts1.Start))
+       range2 := time.Time(ts2.End).Sub(time.Time(ts2.Start))
        for name := range ts1.Data {
-               if len(ts1.Data[name]) != len(ts2.Data[name]) {
-                       return fmt.Errorf("Time-series %q is not aligned", name)
+               l1, l2 := len(ts1.Data[name]), len(ts2.Data[name])
+               if l1 <= 1 || l2 <= 1 {
+                       if l1 == l2 && range1 == range2 {
+                               continue
+                       }
+                       return fmt.Errorf("invalid value count for %q: %d != %d", name, l1, l2)
                }
+
+               step1, step2 := range1/time.Duration(l1-1), range2/time.Duration(l2-1)
+               if step1 != step2 || step1 <= 0 {
+                       return fmt.Errorf("mismatching steps sizes for %q: %v != %v", name, step1, step2)
+               }
+
+               for _, ts := range []*sysdb.Timeseries{ts1, ts2} {
+                       a := start.Sub(time.Time(ts.Start)) / step1
+                       b := end.Sub(time.Time(ts.Start)) / step1
+                       ts.Data[name] = ts.Data[name][a : b+1]
+               }
+       }
+
+       ts1.Start, ts2.Start = sysdb.Time(start), sysdb.Time(start)
+       ts1.End, ts2.End = sysdb.Time(end), sysdb.Time(end)
+       return nil
+}
+
+// sum is an aggregation function that adds ts2 to ts1. The timeseries will be
+// aligned.
+func sum(ts1, ts2 *sysdb.Timeseries) error {
+       if err := align(ts1, ts2); err != nil {
+               return fmt.Errorf("Incompatible time-series: %v", err)
+       }
+
+       for name := range ts1.Data {
                for i := range ts1.Data[name] {
-                       if !ts1.Data[name][i].Timestamp.Equal(ts2.Data[name][i].Timestamp) {
-                               return fmt.Errorf("Time-series %q is not aligned", name)
-                       }
                        ts1.Data[name][i].Value += ts2.Data[name][i].Value
                }
        }

diff --git a/graph/graph_test.go b/graph/graph_test.go
new file mode 100644 (file)
index 0000000..b0e98c4
--- /dev/null
+++ b/graph/graph_test.go
@@ -0,0 +1,193 @@
+//
+// Copyright (C) 2016 Sebastian 'tokkee' Harl <sh@tokkee.org>
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+// 1. Redistributions of source code must retain the above copyright
+//    notice, this list of conditions and the following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright
+//    notice, this list of conditions and the following disclaimer in the
+//    documentation and/or other materials provided with the distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
+// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+// OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+// WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+// OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+// ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package graph
+
+import (
+       "reflect"
+       "testing"
+       "time"
+
+       "github.com/sysdb/go/sysdb"
+)
+
+func TestAlign(t *testing.T) {
+       for _, test := range []struct {
+               ts1, ts2 *sysdb.Timeseries
+               want     *sysdb.Timeseries
+       }{
+               {
+                       ts1: &sysdb.Timeseries{
+                               Start: ts(4, 5, 0),
+                               End:   ts(4, 10, 0),
+                               Data: map[string][]sysdb.DataPoint{
+                                       "value": []sysdb.DataPoint{
+                                               {ts(4, 5, 0), 0.0},
+                                               {ts(4, 6, 0), 0.0},
+                                               {ts(4, 7, 0), 1.0},
+                                               {ts(4, 8, 0), 1.0},
+                                               {ts(4, 9, 0), 0.0},
+                                               {ts(4, 10, 0), 0.0},
+                                       },
+                               },
+                       },
+                       ts2: &sysdb.Timeseries{
+                               Start: ts(4, 7, 0),
+                               End:   ts(4, 8, 0),
+                               Data: map[string][]sysdb.DataPoint{
+                                       "value": []sysdb.DataPoint{
+                                               {ts(4, 7, 0), 1.0},
+                                               {ts(4, 8, 0), 1.0},
+                                       },
+                               },
+                       },
+                       want: &sysdb.Timeseries{
+                               Start: ts(4, 7, 0),
+                               End:   ts(4, 8, 0),
+                               Data: map[string][]sysdb.DataPoint{
+                                       "value": []sysdb.DataPoint{
+                                               {ts(4, 7, 0), 1.0},
+                                               {ts(4, 8, 0), 1.0},
+                                       },
+                               },
+                       },
+               },
+               {
+                       ts1: &sysdb.Timeseries{
+                               Start: ts(4, 7, 0),
+                               End:   ts(4, 8, 0),
+                               Data: map[string][]sysdb.DataPoint{
+                                       "value": []sysdb.DataPoint{
+                                               {ts(4, 7, 0), 1.0},
+                                               {ts(4, 8, 0), 1.0},
+                                       },
+                               },
+                       },
+                       ts2: &sysdb.Timeseries{
+                               Start: ts(4, 7, 0),
+                               End:   ts(4, 8, 0),
+                               Data: map[string][]sysdb.DataPoint{
+                                       "value": []sysdb.DataPoint{
+                                               {ts(4, 7, 0), 1.0},
+                                               {ts(4, 8, 0), 1.0},
+                                       },
+                               },
+                       },
+                       want: &sysdb.Timeseries{
+                               Start: ts(4, 7, 0),
+                               End:   ts(4, 8, 0),
+                               Data: map[string][]sysdb.DataPoint{
+                                       "value": []sysdb.DataPoint{
+                                               {ts(4, 7, 0), 1.0},
+                                               {ts(4, 8, 0), 1.0},
+                                       },
+                               },
+                       },
+               },
+               {
+                       ts1: &sysdb.Timeseries{
+                               Start: ts(4, 5, 0),
+                               End:   ts(4, 10, 0),
+                               Data: map[string][]sysdb.DataPoint{
+                                       "value": []sysdb.DataPoint{
+                                               {ts(4, 5, 0), 0.0},
+                                               {ts(4, 6, 0), 0.0},
+                                               {ts(4, 7, 0), 0.0},
+                                               {ts(4, 8, 0), 1.0},
+                                               {ts(4, 9, 0), 1.0},
+                                               {ts(4, 10, 0), 1.0},
+                                       },
+                               },
+                       },
+                       ts2: &sysdb.Timeseries{
+                               Start: ts(4, 8, 0),
+                               End:   ts(4, 12, 0),
+                               Data: map[string][]sysdb.DataPoint{
+                                       "value": []sysdb.DataPoint{
+                                               {ts(4, 8, 0), 1.0},
+                                               {ts(4, 9, 0), 1.0},
+                                               {ts(4, 10, 0), 1.0},
+                                               {ts(4, 11, 0), 0.0},
+                                               {ts(4, 12, 0), 0.0},
+                                       },
+                               },
+                       },
+                       want: &sysdb.Timeseries{
+                               Start: ts(4, 8, 0),
+                               End:   ts(4, 10, 0),
+                               Data: map[string][]sysdb.DataPoint{
+                                       "value": []sysdb.DataPoint{
+                                               {ts(4, 8, 0), 1.0},
+                                               {ts(4, 9, 0), 1.0},
+                                               {ts(4, 10, 0), 1.0},
+                                       },
+                               },
+                       },
+               },
+               {
+                       ts1: &sysdb.Timeseries{
+                               Start: ts(4, 7, 0),
+                               End:   ts(4, 7, 0),
+                               Data: map[string][]sysdb.DataPoint{
+                                       "value": []sysdb.DataPoint{
+                                               {ts(4, 7, 0), 1.0},
+                                       },
+                               },
+                       },
+                       ts2: &sysdb.Timeseries{
+                               Start: ts(4, 7, 0),
+                               End:   ts(4, 7, 0),
+                               Data: map[string][]sysdb.DataPoint{
+                                       "value": []sysdb.DataPoint{
+                                               {ts(4, 7, 0), 1.0},
+                                       },
+                               },
+                       },
+                       want: &sysdb.Timeseries{
+                               Start: ts(4, 7, 0),
+                               End:   ts(4, 7, 0),
+                               Data: map[string][]sysdb.DataPoint{
+                                       "value": []sysdb.DataPoint{
+                                               {ts(4, 7, 0), 1.0},
+                                       },
+                               },
+                       },
+               },
+       } {
+               if err := align(test.ts1, test.ts2); err != nil {
+                       t.Errorf("align(%v, %v) = %v; want <nil>", test.ts1, test.ts2, err)
+               }
+
+               if !reflect.DeepEqual(test.ts1, test.want) || !reflect.DeepEqual(test.ts2, test.want) {
+                       t.Errorf("align() unexpected result %v, %v; want %v", test.ts1, test.ts2, test.want)
+               }
+       }
+}
+
+func ts(hour, min, sec int) sysdb.Time {
+       return sysdb.Time(time.Date(2016, 1, 1, hour, min, sec, 0, time.UTC))
+}
+
+// vim: set tw=78 sw=4 sw=4 noexpandtab :