Log4j2 plugin to filter on stack traces matching a text

Signed-off-by: Fabio Di Fabio <[email protected]>

util/src/main/java/org/hyperledger/besu/util/log4j/plugin/StackTraceMatchFilter.java

@@ -0,0 +1,120 @@
+/*
+ * Copyright contributors to Hyperledger Besu.
+ *
+ * Licensed 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.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package org.hyperledger.besu.util.log4j.plugin;
+
+import java.util.Arrays;
+
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.Marker;
+import org.apache.logging.log4j.core.LogEvent;
+import org.apache.logging.log4j.core.Logger;
+import org.apache.logging.log4j.core.config.plugins.Plugin;
+import org.apache.logging.log4j.core.config.plugins.PluginBuilderAttribute;
+import org.apache.logging.log4j.core.config.plugins.PluginBuilderFactory;
+import org.apache.logging.log4j.core.filter.AbstractFilter;
+import org.apache.logging.log4j.message.Message;
+
+/** Matches a text in the stack trace */
+@Plugin(
+    name = "StackTraceMatchFilter",
+    category = "Core",
+    elementType = "filter",
+    printObject = true)
+public class StackTraceMatchFilter extends AbstractFilter {
+  private final String text;
+
+  private StackTraceMatchFilter(final String text, final Result onMatch, final Result onMismatch) {
+    super(onMatch, onMismatch);
+    this.text = text;
+  }
+
+  @Override
+  public Result filter(
+      final Logger logger,
+      final Level level,
+      final Marker marker,
+      final Object msg,
+      final Throwable t) {
+    return filter(t);
+  }
+
+  @Override
+  public Result filter(
+      final Logger logger,
+      final Level level,
+      final Marker marker,
+      final Message msg,
+      final Throwable t) {
+    return filter(t);
+  }
+
+  @Override
+  public Result filter(final LogEvent event) {
+    return filter(event.getThrown());
+  }
+
+  private Result filter(final Throwable t) {
+    if (t != null) {
+      return Arrays.stream(t.getStackTrace())
+              .map(StackTraceElement::getClassName)
+              .anyMatch(cn -> cn.contains(text))
+          ? onMatch
+          : onMismatch;
+    }
+    return Result.NEUTRAL;
+  }
+
+  @Override
+  public String toString() {
+    return text;
+  }
+
+  /**
+   * Create a new builder
+   *
+   * @return a new builder
+   */
+  @PluginBuilderFactory
+  public static StackTraceMatchFilter.Builder newBuilder() {
+    return new StackTraceMatchFilter.Builder();
+  }
+
+  /** Builder for StackTraceMatchFilter */
+  public static class Builder extends AbstractFilterBuilder<StackTraceMatchFilter.Builder>
+      implements org.apache.logging.log4j.core.util.Builder<StackTraceMatchFilter> {
+    @PluginBuilderAttribute private String text = "";
+
+    /** Default constructor */
+    public Builder() {
+      // here to make javadoc happy
+    }
+
+    /**
+     * Set the string to match in the stack trace
+     *
+     * @param text the match string
+     * @return this builder
+     */
+    public StackTraceMatchFilter.Builder setMatchString(final String text) {
+      this.text = text;
+      return this;
+    }
+
+    @Override
+    public StackTraceMatchFilter build() {
+      return new StackTraceMatchFilter(this.text, this.getOnMatch(), this.getOnMismatch());
+    }
+  }
+}