1u0 commented on a change in pull request #9870: [FLINK-14350][metrics]
Introduce dedicated MetricScope
URL: https://github.com/apache/flink/pull/9870#discussion_r335759928
##########
File path:
flink-runtime/src/main/java/org/apache/flink/runtime/metrics/groups/FrontMetricGroup.java
##########
@@ -30,28 +34,54 @@
*/
public class FrontMetricGroup<P extends AbstractMetricGroup<?>> extends
ProxyMetricGroup<P> {
- protected int reporterIndex;
+ private final ReporterIndexInjectingMetricScope scope;
public FrontMetricGroup(int reporterIndex, P reference) {
super(reference);
- this.reporterIndex = reporterIndex;
+ this.scope = new
ReporterIndexInjectingMetricScope(reporterIndex,
this.parentMetricGroup.getScope());
}
@Override
public String getMetricIdentifier(String metricName) {
- return parentMetricGroup.getMetricIdentifier(metricName, null,
this.reporterIndex);
+ return scope.getMetricIdentifier(metricName);
}
@Override
public String getMetricIdentifier(String metricName, CharacterFilter
filter) {
- return parentMetricGroup.getMetricIdentifier(metricName,
filter, this.reporterIndex);
+ return scope.getMetricIdentifier(metricName, filter);
}
public String getLogicalScope(CharacterFilter filter) {
return parentMetricGroup.getLogicalScope(filter);
}
public String getLogicalScope(CharacterFilter filter, char delimiter) {
- return parentMetricGroup.getLogicalScope(filter, delimiter,
this.reporterIndex);
+ return parentMetricGroup.getLogicalScope(filter, delimiter,
scope.reporterIndex);
+ }
+
+ private static final class ReporterIndexInjectingMetricScope implements
MetricScope {
+
+ private final int reporterIndex;
+ private final InternalMetricScope scope;
+
+ private ReporterIndexInjectingMetricScope(int reporterIndex,
InternalMetricScope scope) {
+ this.reporterIndex = reporterIndex;
+ this.scope = scope;
+ }
+
+ @Override
+ public Map<String, String> getAllVariables() {
+ return scope.getAllVariables();
+ }
+
+ @Override
+ public String getMetricIdentifier(String metricName) {
+ return scope.getMetricIdentifier(metricName, s -> s,
reporterIndex);
+ }
+
+ @Override
+ public String getMetricIdentifier(String metricName,
CharacterFilter filter) {
+ return scope.getMetricIdentifier(metricName, filter,
reporterIndex);
+ }
Review comment:
**Side note:** this is potentially error prone, it's possible that `filter`
is non trivial `CharacterFilter` (a case when results differ for different
filters) and we are calling both methods for the same metric reporter.
In such situation the cached value would be the one that was called first.
Although, this error proneness existed in the old code.
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