org.apache.beam.sdk.metrics

Class MetricFiltering

java.lang.Object

org.apache.beam.sdk.metrics.MetricFiltering

public class MetricFiltering
extends java.lang.Object

Implements matching for metrics filters. Specifically, matching for metric name, namespace, and step name.

Method Summary

Modifier and Type	Method and Description
static boolean	matches(MetricsFilter filter, MetricKey key) Matching logic is implemented here rather than in MetricsFilter because we would like MetricsFilter to act as a "dumb" value-object, with the possibility of replacing it with a Proto/JSON/etc.
static boolean	matchesScope(java.lang.String actualScope, java.util.Set<java.lang.String> scopes) matchesScope(actualScope, scopes) returns true if the scope of a metric is matched by any of the filters in scopes.
static boolean	subPathMatches(java.lang.String haystack, java.lang.String needle) subPathMatches(haystack, needle) returns true if needle represents a path within haystack.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

matches

public static boolean matches(MetricsFilter filter,
                              MetricKey key)

Matching logic is implemented here rather than in MetricsFilter because we would like MetricsFilter to act as a "dumb" value-object, with the possibility of replacing it with a Proto/JSON/etc. schema object.

Parameters:

filter - MetricsFilter with the matching information of an actual metric

key - MetricKey with the information of a metric

Returns:

whether the filter matches the key or not

subPathMatches

public static boolean subPathMatches(java.lang.String haystack,
                                     java.lang.String needle)

subPathMatches(haystack, needle) returns true if needle represents a path within haystack. For example, "foo/bar" is in "a/foo/bar/b", but not "a/fool/bar/b" or "a/foo/bart/b".

matchesScope

public static boolean matchesScope(java.lang.String actualScope,
                                   java.util.Set<java.lang.String> scopes)

matchesScope(actualScope, scopes) returns true if the scope of a metric is matched by any of the filters in scopes. A metric scope is a path of type "A/B/D". A path is matched by a filter if the filter is equal to the path (e.g. "A/B/D", or if it represents a subpath within it (e.g. "A/B" or "B/D", but not "A/D").

Per https://docs.oracle.com/en/java/javase/14/docs/api/java.base/java/util/Set.html "sets contain ... at most one null element" / "Some set implementations have restrictions on the elements that they may contain. For example, some implementations prohibit null elements". Since sets cannot in general contain null it is not safe to check for membership of null, so the caller must determine what to do with a null actualScope.