stats: sanitize metric names

If the configuration contains a key value with a `:` or `|`, e.g.

```
- key: path
  value: "/foo:*"
  rate_limit:
    unit: minute
    requests_per_unit: 20
```

the reported statsd metrics are malformed.

Signed-off-by: Lukasz Szczesny <[email protected]>

src/stats/manager_impl.go

@@ -5,6 +5,7 @@ import (
 	logger "github.com/sirupsen/logrus"
 
 	"github.com/envoyproxy/ratelimit/src/settings"
+	"github.com/envoyproxy/ratelimit/src/utils"
 )
 
 func NewStatManager(store gostats.Store, settings settings.Settings) *ManagerImpl {
@@ -28,6 +29,7 @@ func (this *ManagerImpl) NewStats(key string) RateLimitStats {
 	ret := RateLimitStats{}
 	logger.Debugf("Creating stats for key: '%s'", key)
 	ret.Key = key
+	key = utils.SanitizeStatName(key)
 	ret.TotalHits = this.rlStatsScope.NewCounter(key + ".total_hits")
 	ret.OverLimit = this.rlStatsScope.NewCounter(key + ".over_limit")
 	ret.NearLimit = this.rlStatsScope.NewCounter(key + ".near_limit")

src/utils/utilities.go

@@ -61,3 +61,9 @@ func MaskCredentialsInUrl(url string) string {
 
 	return strings.Join(urls, ",")
 }
+
+// Remove invalid characters from the stat name.
+func SanitizeStatName(s string) string {
+	r := strings.NewReplacer(":", "_", "|", "_")
+	return r.Replace(s)
+}

test/mocks/stats/manager.go

@@ -5,6 +5,7 @@ import (
 	logger "github.com/sirupsen/logrus"
 
 	"github.com/envoyproxy/ratelimit/src/stats"
+	"github.com/envoyproxy/ratelimit/src/utils"
 )
 
 type MockStatManager struct {
@@ -36,6 +37,7 @@ func (m *MockStatManager) NewStats(key string) stats.RateLimitStats {
 	ret := stats.RateLimitStats{}
 	logger.Debugf("outputing test gostats %s", key)
 	ret.Key = key
+	key = utils.SanitizeStatName(key)
 	ret.TotalHits = m.store.NewCounter(key + ".total_hits")
 	ret.OverLimit = m.store.NewCounter(key + ".over_limit")
 	ret.NearLimit = m.store.NewCounter(key + ".near_limit")