blob: 0937f4aedf7c7d7cff77d236ea8681cbdc81f0a5 [file] [log] [blame]
divyadesai19009132020-03-04 12:58:08 +00001package metrics
2
3import (
4 "bytes"
5 "fmt"
6 "io"
7 "os"
8 "os/signal"
9 "strings"
10 "sync"
11 "syscall"
12)
13
14// InmemSignal is used to listen for a given signal, and when received,
15// to dump the current metrics from the InmemSink to an io.Writer
16type InmemSignal struct {
17 signal syscall.Signal
18 inm *InmemSink
19 w io.Writer
20 sigCh chan os.Signal
21
22 stop bool
23 stopCh chan struct{}
24 stopLock sync.Mutex
25}
26
27// NewInmemSignal creates a new InmemSignal which listens for a given signal,
28// and dumps the current metrics out to a writer
29func NewInmemSignal(inmem *InmemSink, sig syscall.Signal, w io.Writer) *InmemSignal {
30 i := &InmemSignal{
31 signal: sig,
32 inm: inmem,
33 w: w,
34 sigCh: make(chan os.Signal, 1),
35 stopCh: make(chan struct{}),
36 }
37 signal.Notify(i.sigCh, sig)
38 go i.run()
39 return i
40}
41
42// DefaultInmemSignal returns a new InmemSignal that responds to SIGUSR1
43// and writes output to stderr. Windows uses SIGBREAK
44func DefaultInmemSignal(inmem *InmemSink) *InmemSignal {
45 return NewInmemSignal(inmem, DefaultSignal, os.Stderr)
46}
47
48// Stop is used to stop the InmemSignal from listening
49func (i *InmemSignal) Stop() {
50 i.stopLock.Lock()
51 defer i.stopLock.Unlock()
52
53 if i.stop {
54 return
55 }
56 i.stop = true
57 close(i.stopCh)
58 signal.Stop(i.sigCh)
59}
60
61// run is a long running routine that handles signals
62func (i *InmemSignal) run() {
63 for {
64 select {
65 case <-i.sigCh:
66 i.dumpStats()
67 case <-i.stopCh:
68 return
69 }
70 }
71}
72
73// dumpStats is used to dump the data to output writer
74func (i *InmemSignal) dumpStats() {
75 buf := bytes.NewBuffer(nil)
76
77 data := i.inm.Data()
78 // Skip the last period which is still being aggregated
79 for j := 0; j < len(data)-1; j++ {
80 intv := data[j]
81 intv.RLock()
82 for _, val := range intv.Gauges {
83 name := i.flattenLabels(val.Name, val.Labels)
84 fmt.Fprintf(buf, "[%v][G] '%s': %0.3f\n", intv.Interval, name, val.Value)
85 }
86 for name, vals := range intv.Points {
87 for _, val := range vals {
88 fmt.Fprintf(buf, "[%v][P] '%s': %0.3f\n", intv.Interval, name, val)
89 }
90 }
91 for _, agg := range intv.Counters {
92 name := i.flattenLabels(agg.Name, agg.Labels)
93 fmt.Fprintf(buf, "[%v][C] '%s': %s\n", intv.Interval, name, agg.AggregateSample)
94 }
95 for _, agg := range intv.Samples {
96 name := i.flattenLabels(agg.Name, agg.Labels)
97 fmt.Fprintf(buf, "[%v][S] '%s': %s\n", intv.Interval, name, agg.AggregateSample)
98 }
99 intv.RUnlock()
100 }
101
102 // Write out the bytes
103 i.w.Write(buf.Bytes())
104}
105
106// Flattens the key for formatting along with its labels, removes spaces
107func (i *InmemSignal) flattenLabels(name string, labels []Label) string {
108 buf := bytes.NewBufferString(name)
109 replacer := strings.NewReplacer(" ", "_", ":", "_")
110
111 for _, label := range labels {
112 replacer.WriteString(buf, ".")
113 replacer.WriteString(buf, label.Value)
114 }
115
116 return buf.String()
117}