[GitHub] [zookeeper] muse-dev[bot] commented on a change in pull request #1644: ZOOKEEPER-4211: Expose Per Namespace Quota Metrics to Prometheus

[GitBox <gi...@apache.org>]

muse-dev[bot] commented on a change in pull request #1644:
URL: https://github.com/apache/zookeeper/pull/1644#discussion_r605980043



##########
File path: zookeeper-server/src/main/java/org/apache/zookeeper/server/util/QuotaMetricsUtils.java
##########
@@ -0,0 +1,169 @@
+/*
+ * 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.zookeeper.server.util;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import org.apache.zookeeper.Quotas;
+import org.apache.zookeeper.StatsTrack;
+import org.apache.zookeeper.common.PathUtils;
+import org.apache.zookeeper.server.DataNode;
+import org.apache.zookeeper.server.DataTree;
+
+public final class QuotaMetricsUtils {
+    public static final String QUOTA_COUNT_LIMIT_PER_NAMESPACE = "quota_count_limit_per_namespace";
+    public static final String QUOTA_BYTES_LIMIT_PER_NAMESPACE = "quota_bytes_limit_per_namespace";
+    public static final String QUOTA_COUNT_USAGE_PER_NAMESPACE = "quota_count_usage_per_namespace";
+    public static final String QUOTA_BYTES_USAGE_PER_NAMESPACE = "quota_bytes_usage_per_namespace";
+    public static final String QUOTA_EXCEEDED_ERROR_PER_NAMESPACE = "quota_exceeded_error_per_namespace";
+
+    enum QUOTA_LIMIT_USAGE_METRIC_TYPE {QUOTA_COUNT_LIMIT, QUOTA_BYTES_LIMIT, QUOTA_COUNT_USAGE, QUOTA_BYTES_USAGE}
+    static final String LIMIT_END_STRING = "/" + Quotas.limitNode;
+    static final String STATS_END_STRING = "/" + Quotas.statNode;
+
+    private QuotaMetricsUtils() {
+    }
+
+    /**
+     * Traverse the quota subtree and return per namespace quota count limit
+     *
+     * @param dataTree dataTree that contains the quota limit and usage data
+     * @return a map with top namespace as the key and quota count limit as the value
+     *
+     */
+    public static Map<String, Number> getQuotaCountLimit(final DataTree dataTree) {
+        return getQuotaLimitOrUsage(dataTree, QUOTA_LIMIT_USAGE_METRIC_TYPE.QUOTA_COUNT_LIMIT);
+    }
+
+    /**
+     * Traverse the quota subtree and return per namespace quota bytes limit
+     *`
+     * @param dataTree dataTree that contains the quota limit and usage data
+     * @return a map with top namespace as the key and quota bytes limit as the value
+     *
+     */
+    public static Map<String, Number> getQuotaBytesLimit(final DataTree dataTree) {
+        return getQuotaLimitOrUsage(dataTree, QUOTA_LIMIT_USAGE_METRIC_TYPE.QUOTA_BYTES_LIMIT);
+    }
+
+    /**
+     * Traverse the quota subtree and return per namespace quota count usage
+     *
+     * @param dataTree dataTree that contains the quota limit and usage data
+     * @return a map with top namespace as the key and quota count usage as the value
+     *
+     */
+    public static Map<String, Number> getQuotaCountUsage(final DataTree dataTree) {
+        return getQuotaLimitOrUsage(dataTree, QUOTA_LIMIT_USAGE_METRIC_TYPE.QUOTA_COUNT_USAGE);
+    }
+
+    /**
+     * Traverse the quota subtree and return per namespace quota bytes usage
+     *
+     * @param dataTree dataTree that contains the quota limit and usage data
+     * @return  a map with top namespace as the key and quota bytes usage as the value
+     *
+     */
+    public static Map<String, Number> getQuotaBytesUsage(final DataTree dataTree) {
+        return getQuotaLimitOrUsage(dataTree, QUOTA_LIMIT_USAGE_METRIC_TYPE.QUOTA_BYTES_USAGE);
+    }
+
+    // traverse the quota subtree and read the quota limit or usage data
+    private static Map<String, Number> getQuotaLimitOrUsage(final DataTree dataTree,
+                                                            final QUOTA_LIMIT_USAGE_METRIC_TYPE type) {
+        final Map<String, Number> metricsMap = new ConcurrentHashMap<>();
+        if (dataTree != null) {
+            getQuotaLimitOrUsage(Quotas.quotaZookeeper, metricsMap, type, dataTree);
+        }
+        return metricsMap;
+    }
+
+    static void getQuotaLimitOrUsage(final String path,
+                                     final Map<String, Number> metricsMap,
+                                     final QUOTA_LIMIT_USAGE_METRIC_TYPE type,
+                                     final DataTree dataTree) {
+        final DataNode node = dataTree.getNode(path);
+        if (node == null) {
+            return;
+        }
+        final List<String> children;
+        synchronized (node) {
+            children = new ArrayList<>(node.getChildren());
+        }
+        if (children.size() == 0) {
+            if (shouldCollect(path, type)) {
+                collectQuotaLimitOrUsage(path, node, metricsMap, type);

Review comment:
       *THREAD_SAFETY_VIOLATION:*  Unprotected write. Non-private method `QuotaMetricsUtils.getQuotaLimitOrUsage(...)` indirectly mutates container `metricsMap` via call to `Map.put(...)` outside of synchronization.
    Reporting because this access may occur on a background thread.
   (at-me [in a reply](https://docs.muse.dev/docs/talk-to-muse/) with `help` or `ignore`)




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