added prometheus metrics

1 files changed, 28 insertions, 0 deletions

diff --git a/metric.go b/metric.go
new file mode 100644
index 0000000..7179458
--- /dev/null
+++ b/metric.go
@@ -0,0 +1,28 @@
+package stfe
+
+import (
+	"sync"
+
+	"github.com/google/trillian/monitoring"
+	"github.com/google/trillian/monitoring/prometheus"
+)
+
+var (
+	once             sync.Once
+	reqcnt           monitoring.Counter   // number of incoming http requests
+	rspcnt           monitoring.Counter   // number of valid http responses
+	latency          monitoring.Histogram // request-response latency
+	lastSdiTimestamp monitoring.Gauge     // unix timestamp from the most recent sdi
+	lastSthTimestamp monitoring.Gauge     // unix timestamp from the most recent sth
+	lastSthSize      monitoring.Gauge     // tree size of most recent sth
+)
+
+func metricSetup() {
+	mf := prometheus.MetricFactory{}
+	reqcnt = mf.NewCounter("http_req", "number of http requests", "logid", "endpoint")
+	rspcnt = mf.NewCounter("http_rsp", "number of http requests", "logid", "endpoint", "status")
+	latency = mf.NewHistogram("http_latency", "http request-response latency", "logid", "endpoint", "status")
+	lastSthTimestamp = mf.NewGauge("last_sth_timestamp", "unix timestamp while handling the most recent sth", "logid")
+	lastSdiTimestamp = mf.NewGauge("last_sdi_timestamp", "unix timestamp while handling the most recent sdi", "logid")
+	lastSthSize = mf.NewGauge("last_sth_size", "most recent sth tree size", "logid")
+}