Metrics: Add prefix for graphite export (#99)

Author: And1sS

src/main/java/org/prebid/cache/config/MetricsConfig.java

@@ -2,7 +2,10 @@
 
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.config.NamingConvention;
+import org.apache.commons.lang3.StringUtils;
+import org.springframework.beans.factory.annotation.Value;
 import org.springframework.boot.actuate.autoconfigure.metrics.MeterRegistryCustomizer;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
@@ -14,4 +17,16 @@ MeterRegistryCustomizer<MeterRegistry> identityNamingConventionMeterCustomizer()
         // To preserve metric names as they defined in code
         return registry -> registry.config().namingConvention(NamingConvention.identity);
     }
+
+    @Bean
+    @ConditionalOnProperty(name = "management.metrics.export.graphite.enabled", havingValue = "true")
+    MeterRegistryCustomizer<MeterRegistry> graphitePrefixMeterCustomizer(
+            @Value("${management.metrics.export.graphite.prefix:}") String prefix) {
+
+        return registry -> {
+            if (StringUtils.isNotBlank(prefix)) {
+                registry.config().commonTags("prefix", prefix);
+            }
+        };
+    }
 }

src/main/resources/application.yml

@@ -38,9 +38,11 @@ management:
         enabled: false
         host: localhost
         port: 2003
+        protocol: plaintext
         step: 1m
         tags-as-prefix:
-        - prebid
+          - prefix
+        prefix: prebid
 
 # circuit breaker
 circuitbreaker: