Compatible with parsing for block_cache_usage (#26)

exporter/info.go

@@ -249,13 +249,25 @@ func (e *Exporter) handleMetricsReplication(ch chan<- prometheus.Metric, masterH
 }
 
 func (e *Exporter) handleMetricsRocksDB(ch chan<- prometheus.Metric, fieldKey string, fieldValue string) {
+	sharedMetric := []string{"block_cache_usage"}
+	for _, field := range sharedMetric {
+		// format like `block_cache_usage:0`
+		if strings.Compare(fieldKey, field) == 0 {
+			if statValue, err := strconv.ParseFloat(fieldValue, 64); err == nil {
+				e.registerConstMetricGauge(ch, fieldKey, statValue, "-")
+			}
+			// return ASAP
+			return
+		}
+	}
+
 	prefixs := []string{
 		"block_cache_usage", "block_cache_pinned_usage", "index_and_filter_cache_usage", "estimate_keys",
 		"level0_file_limit_slowdown", "level0_file_limit_stop", "pending_compaction_bytes_slowdown",
 		"pending_compaction_bytes_stop", "memtable_count_limit_slowdown", "memtable_count_limit_stop",
 	}
 	for _, prefix := range prefixs {
-		// format like `block_cache_usage[default]:0`
+		// format like `estimate_keys[default]:0`
 		if strings.HasPrefix(fieldKey, prefix) {
 			fields := strings.Split(fieldKey, "[")
 			if len(fields) != 2 {
@@ -266,6 +278,7 @@ func (e *Exporter) handleMetricsRocksDB(ch chan<- prometheus.Metric, fieldKey st
 			if statValue, err := strconv.ParseFloat(fieldValue, 64); err == nil {
 				e.registerConstMetricGauge(ch, metricName, statValue, columnFamily)
 			}
+			return
 		}
 	}
 }