Scott Baker | 2d89798 | 2019-09-24 11:50:08 -0700 | [diff] [blame^] | 1 | package metrics |
| 2 | |
| 3 | import ( |
| 4 | "bufio" |
| 5 | "fmt" |
| 6 | "log" |
| 7 | "net" |
| 8 | "net/url" |
| 9 | "strings" |
| 10 | "time" |
| 11 | ) |
| 12 | |
| 13 | const ( |
| 14 | // We force flush the statsite metrics after this period of |
| 15 | // inactivity. Prevents stats from getting stuck in a buffer |
| 16 | // forever. |
| 17 | flushInterval = 100 * time.Millisecond |
| 18 | ) |
| 19 | |
| 20 | // NewStatsiteSinkFromURL creates an StatsiteSink from a URL. It is used |
| 21 | // (and tested) from NewMetricSinkFromURL. |
| 22 | func NewStatsiteSinkFromURL(u *url.URL) (MetricSink, error) { |
| 23 | return NewStatsiteSink(u.Host) |
| 24 | } |
| 25 | |
| 26 | // StatsiteSink provides a MetricSink that can be used with a |
| 27 | // statsite metrics server |
| 28 | type StatsiteSink struct { |
| 29 | addr string |
| 30 | metricQueue chan string |
| 31 | } |
| 32 | |
| 33 | // NewStatsiteSink is used to create a new StatsiteSink |
| 34 | func NewStatsiteSink(addr string) (*StatsiteSink, error) { |
| 35 | s := &StatsiteSink{ |
| 36 | addr: addr, |
| 37 | metricQueue: make(chan string, 4096), |
| 38 | } |
| 39 | go s.flushMetrics() |
| 40 | return s, nil |
| 41 | } |
| 42 | |
| 43 | // Close is used to stop flushing to statsite |
| 44 | func (s *StatsiteSink) Shutdown() { |
| 45 | close(s.metricQueue) |
| 46 | } |
| 47 | |
| 48 | func (s *StatsiteSink) SetGauge(key []string, val float32) { |
| 49 | flatKey := s.flattenKey(key) |
| 50 | s.pushMetric(fmt.Sprintf("%s:%f|g\n", flatKey, val)) |
| 51 | } |
| 52 | |
| 53 | func (s *StatsiteSink) SetGaugeWithLabels(key []string, val float32, labels []Label) { |
| 54 | flatKey := s.flattenKeyLabels(key, labels) |
| 55 | s.pushMetric(fmt.Sprintf("%s:%f|g\n", flatKey, val)) |
| 56 | } |
| 57 | |
| 58 | func (s *StatsiteSink) EmitKey(key []string, val float32) { |
| 59 | flatKey := s.flattenKey(key) |
| 60 | s.pushMetric(fmt.Sprintf("%s:%f|kv\n", flatKey, val)) |
| 61 | } |
| 62 | |
| 63 | func (s *StatsiteSink) IncrCounter(key []string, val float32) { |
| 64 | flatKey := s.flattenKey(key) |
| 65 | s.pushMetric(fmt.Sprintf("%s:%f|c\n", flatKey, val)) |
| 66 | } |
| 67 | |
| 68 | func (s *StatsiteSink) IncrCounterWithLabels(key []string, val float32, labels []Label) { |
| 69 | flatKey := s.flattenKeyLabels(key, labels) |
| 70 | s.pushMetric(fmt.Sprintf("%s:%f|c\n", flatKey, val)) |
| 71 | } |
| 72 | |
| 73 | func (s *StatsiteSink) AddSample(key []string, val float32) { |
| 74 | flatKey := s.flattenKey(key) |
| 75 | s.pushMetric(fmt.Sprintf("%s:%f|ms\n", flatKey, val)) |
| 76 | } |
| 77 | |
| 78 | func (s *StatsiteSink) AddSampleWithLabels(key []string, val float32, labels []Label) { |
| 79 | flatKey := s.flattenKeyLabels(key, labels) |
| 80 | s.pushMetric(fmt.Sprintf("%s:%f|ms\n", flatKey, val)) |
| 81 | } |
| 82 | |
| 83 | // Flattens the key for formatting, removes spaces |
| 84 | func (s *StatsiteSink) flattenKey(parts []string) string { |
| 85 | joined := strings.Join(parts, ".") |
| 86 | return strings.Map(func(r rune) rune { |
| 87 | switch r { |
| 88 | case ':': |
| 89 | fallthrough |
| 90 | case ' ': |
| 91 | return '_' |
| 92 | default: |
| 93 | return r |
| 94 | } |
| 95 | }, joined) |
| 96 | } |
| 97 | |
| 98 | // Flattens the key along with labels for formatting, removes spaces |
| 99 | func (s *StatsiteSink) flattenKeyLabels(parts []string, labels []Label) string { |
| 100 | for _, label := range labels { |
| 101 | parts = append(parts, label.Value) |
| 102 | } |
| 103 | return s.flattenKey(parts) |
| 104 | } |
| 105 | |
| 106 | // Does a non-blocking push to the metrics queue |
| 107 | func (s *StatsiteSink) pushMetric(m string) { |
| 108 | select { |
| 109 | case s.metricQueue <- m: |
| 110 | default: |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | // Flushes metrics |
| 115 | func (s *StatsiteSink) flushMetrics() { |
| 116 | var sock net.Conn |
| 117 | var err error |
| 118 | var wait <-chan time.Time |
| 119 | var buffered *bufio.Writer |
| 120 | ticker := time.NewTicker(flushInterval) |
| 121 | defer ticker.Stop() |
| 122 | |
| 123 | CONNECT: |
| 124 | // Attempt to connect |
| 125 | sock, err = net.Dial("tcp", s.addr) |
| 126 | if err != nil { |
| 127 | log.Printf("[ERR] Error connecting to statsite! Err: %s", err) |
| 128 | goto WAIT |
| 129 | } |
| 130 | |
| 131 | // Create a buffered writer |
| 132 | buffered = bufio.NewWriter(sock) |
| 133 | |
| 134 | for { |
| 135 | select { |
| 136 | case metric, ok := <-s.metricQueue: |
| 137 | // Get a metric from the queue |
| 138 | if !ok { |
| 139 | goto QUIT |
| 140 | } |
| 141 | |
| 142 | // Try to send to statsite |
| 143 | _, err := buffered.Write([]byte(metric)) |
| 144 | if err != nil { |
| 145 | log.Printf("[ERR] Error writing to statsite! Err: %s", err) |
| 146 | goto WAIT |
| 147 | } |
| 148 | case <-ticker.C: |
| 149 | if err := buffered.Flush(); err != nil { |
| 150 | log.Printf("[ERR] Error flushing to statsite! Err: %s", err) |
| 151 | goto WAIT |
| 152 | } |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | WAIT: |
| 157 | // Wait for a while |
| 158 | wait = time.After(time.Duration(5) * time.Second) |
| 159 | for { |
| 160 | select { |
| 161 | // Dequeue the messages to avoid backlog |
| 162 | case _, ok := <-s.metricQueue: |
| 163 | if !ok { |
| 164 | goto QUIT |
| 165 | } |
| 166 | case <-wait: |
| 167 | goto CONNECT |
| 168 | } |
| 169 | } |
| 170 | QUIT: |
| 171 | s.metricQueue = nil |
| 172 | } |