PLT-4357 adding performance monitoring (#4622)

* WIP

* WIP

* Adding metrics collection

* updating vendor packages

* Adding metrics to config

* Adding admin console page for perf monitoring

* Updating glide

* switching to tylerb/graceful

vendor/github.com/prometheus/procfs/mdstat_test.go

@@ -0,0 +1,31 @@
+package procfs
+
+import (
+	"testing"
+)
+
+func TestMDStat(t *testing.T) {
+	mdStates, err := FS("fixtures").ParseMDStat()
+	if err != nil {
+		t.Fatalf("parsing of reference-file failed entirely: %s", err)
+	}
+
+	refs := map[string]MDStat{
+		"md3":   MDStat{"md3", "active", 8, 8, 5853468288, 5853468288},
+		"md127": MDStat{"md127", "active", 2, 2, 312319552, 312319552},
+		"md0":   MDStat{"md0", "active", 2, 2, 248896, 248896},
+		"md4":   MDStat{"md4", "inactive", 2, 2, 4883648, 4883648},
+		"md6":   MDStat{"md6", "active", 1, 2, 195310144, 16775552},
+		"md8":   MDStat{"md8", "active", 2, 2, 195310144, 16775552},
+		"md7":   MDStat{"md7", "active", 3, 4, 7813735424, 7813735424},
+	}
+
+	if want, have := len(refs), len(mdStates); want != have {
+		t.Errorf("want %d parsed md-devices, have %d", want, have)
+	}
+	for _, md := range mdStates {
+		if want, have := refs[md.Name], md; want != have {
+			t.Errorf("%s: want %v, have %v", md.Name, want, have)
+		}
+	}
+}