Extract logic to build labeled MetricNames to a util Class

runners/google-cloud-dataflow-java/worker/src/main/java/org/apache/beam/runners/dataflow/worker/MetricsToPerStepNamespaceMetricsConverter.java

@@ -32,6 +32,7 @@
 import java.util.Map.Entry;
 import java.util.Optional;
 import org.apache.beam.sdk.io.gcp.bigquery.BigQuerySinkMetrics;
+import org.apache.beam.sdk.metrics.LabeledMetricNameUtils;
 import org.apache.beam.sdk.metrics.MetricName;
 import org.apache.beam.sdk.util.HistogramData;
 
@@ -52,7 +53,7 @@ private static Optional<MetricValue> convertCounterToMetricValue(
       return Optional.empty();
     }
 
-    return BigQuerySinkMetrics.parseMetricName(metricName.getName())
+    return LabeledMetricNameUtils.parseMetricName(metricName.getName())
         .filter(labeledName -> !labeledName.getBaseName().isEmpty())
         .map(
             labeledName ->
@@ -104,8 +105,8 @@ private static Optional<MetricValue> convertHistogramToMetricValue(
       return Optional.empty();
     }
 
-    Optional<BigQuerySinkMetrics.ParsedMetricName> labeledName =
-        BigQuerySinkMetrics.parseMetricName(metricName.getName());
+    Optional<LabeledMetricNameUtils.ParsedMetricName> labeledName =
+        LabeledMetricNameUtils.parseMetricName(metricName.getName());
     if (!labeledName.isPresent() || labeledName.get().getBaseName().isEmpty()) {
       return Optional.empty();
     }

sdks/java/core/src/main/java/org/apache/beam/sdk/metrics/LabeledMetricNameUtils.java

@@ -0,0 +1,119 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.beam.sdk.metrics;
+
+import com.google.auto.value.AutoValue;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Splitter;
+import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableMap;
+
+/**
+ * Util class for building/parsing labeled {@link MetricName}.
+ */
+public class LabeledMetricNameUtils {
+  // Delimiters. Avoid using delimeters that can be used in metric labels. 
+  // E.g. Avoid using labels that can be used in BigQuery Table Ids. 
+  // ref: https://cloud.google.com/bigquery/docs/tables#table_naming
+  private static final char LABEL_DELIMITER = ';';
+  private static final char METRIC_KV_DELIMITER = ':';
+  private static final char METRIC_NAME_DELIMITER = '*';
+
+  /**
+   * Builder class for a labeled {@code MetricName}. Returns a metric name that merges the baseName
+   * with metricLables formatted as.
+   *
+   * <p>'{baseName}-{metricLabelKey1}:{metricLabelVal1};...{metricLabelKeyN}:{metricLabelValN};'
+   */
+  public static class MetricNameBuilder {
+    private final StringBuilder labeledNameBuilder;
+
+    private MetricNameBuilder(String baseName) {
+      this.labeledNameBuilder = new StringBuilder(baseName + METRIC_NAME_DELIMITER);
+    }
+
+    public static MetricNameBuilder baseNameBuilder(String baseName) {
+      return new MetricNameBuilder(baseName);
+    }
+
+    public void addLabel(String key, String value) {
+      this.labeledNameBuilder
+          .append(key)
+          .append(METRIC_KV_DELIMITER)
+          .append(value)
+          .append(LABEL_DELIMITER);
+    }
+
+    public MetricName build(String metricNamespace) {
+      return MetricName.named(metricNamespace, labeledNameBuilder.toString());
+    }
+  }
+
+  @AutoValue
+  public abstract static class ParsedMetricName {
+    public abstract String getBaseName();
+
+    public abstract Map<String, String> getMetricLabels();
+
+    public static ParsedMetricName create(String baseName, Map<String, String> metricLabels) {
+      return new AutoValue_LabeledMetricNameUtils_ParsedMetricName(baseName, metricLabels);
+    }
+
+    public static ParsedMetricName create(String baseName) {
+      ImmutableMap<String, String> emptyMap = ImmutableMap.of();
+      return new AutoValue_LabeledMetricNameUtils_ParsedMetricName(baseName, emptyMap);
+    }
+  }
+
+  /**
+   * Parse a 'metric name' String that was created with 'MetricNameBuilder'. The input string should
+   * be formatted as.
+   *
+   * <p>'{baseName}*{metricLabelKey1}:{metricLabelVal1};...{metricLabelKeyN}:{metricLabelValN};'
+   *
+   * @param metricName
+   * @return Returns a ParsedMetricName object if the input string is properly formatted. If the
+   *     input string is empty or malformed, returns an empty value.
+   */
+  public static Optional<ParsedMetricName> parseMetricName(String metricName) {
+    if (metricName.isEmpty()) {
+      return Optional.empty();
+    }
+
+    List<String> metricNameSplit =
+        Splitter.on(METRIC_NAME_DELIMITER).limit(2).splitToList(metricName);
+
+    if (metricNameSplit.size() == 0) {
+      return Optional.empty();
+    }
+
+    if (metricNameSplit.size() == 1) {
+      return Optional.of(ParsedMetricName.create(metricNameSplit.get(0)));
+    }
+    // metrcNameSplit is assumed to be size two.
+    Splitter.MapSplitter splitter =
+        Splitter.on(LABEL_DELIMITER).omitEmptyStrings().withKeyValueSeparator(METRIC_KV_DELIMITER);
+    try {
+      Map<String, String> labels = splitter.split(metricNameSplit.get(1));
+      return Optional.of(ParsedMetricName.create(metricNameSplit.get(0), labels));
+    } catch (IllegalArgumentException e) {
+    }
+    return Optional.of(ParsedMetricName.create(metricNameSplit.get(0)));
+  }
+}

sdks/java/core/src/test/java/org/apache/beam/sdk/metrics/LabeledMetricNameUtilsTest.java

@@ -0,0 +1,73 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.beam.sdk.metrics;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.equalTo;
+
+import java.io.Serializable;
+import java.util.Optional;
+import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableMap;
+import org.junit.Test;
+
+public class LabeledMetricNameUtilsTest implements Serializable {
+  @Test
+  public void testParseMetricName_noLabels() {
+    String baseMetricName = "baseMetricName";
+    LabeledMetricNameUtils.ParsedMetricName expectedName =
+        LabeledMetricNameUtils.ParsedMetricName.create(baseMetricName);
+
+    Optional<LabeledMetricNameUtils.ParsedMetricName> parsedMetricName =
+        LabeledMetricNameUtils.parseMetricName(baseMetricName);
+    assertThat(parsedMetricName.isPresent(), equalTo(true));
+    assertThat(parsedMetricName.get(), equalTo(expectedName));
+  }
+
+  @Test
+  public void testParseMetricName_successfulLabels() {
+    String metricName = "baseLabel*key1:val1;key2:val2;key3:val3;";
+    ImmutableMap<String, String> metricLabels =
+        ImmutableMap.of("key1", "val1", "key2", "val2", "key3", "val3");
+    LabeledMetricNameUtils.ParsedMetricName expectedName =
+        LabeledMetricNameUtils.ParsedMetricName.create("baseLabel", metricLabels);
+
+    Optional<LabeledMetricNameUtils.ParsedMetricName> parsedMetricName =
+        LabeledMetricNameUtils.parseMetricName(metricName);
+
+    assertThat(parsedMetricName.isPresent(), equalTo(true));
+    assertThat(parsedMetricName.get(), equalTo(expectedName));
+  }
+
+  @Test
+  public void testParseMetricName_malformedMetricLabels() {
+    String metricName = "baseLabel*malformed_kv_pair;key2:val2;";
+    LabeledMetricNameUtils.ParsedMetricName expectedName =
+        LabeledMetricNameUtils.ParsedMetricName.create("baseLabel");
+
+    Optional<LabeledMetricNameUtils.ParsedMetricName> parsedMetricName =
+        LabeledMetricNameUtils.parseMetricName(metricName);
+
+    assertThat(parsedMetricName.isPresent(), equalTo(true));
+    assertThat(parsedMetricName.get(), equalTo(expectedName));
+  }
+
+  @Test
+  public void testParseMetricName_emptyString() {
+    assertThat(LabeledMetricNameUtils.parseMetricName("").isPresent(), equalTo(false));
+  }
+}