| /* |
| * 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.logging.log4j.layout.json.template.resolver; |
| |
| import org.apache.logging.log4j.ThreadContext; |
| import org.apache.logging.log4j.core.LogEvent; |
| import org.apache.logging.log4j.layout.json.template.util.JsonWriter; |
| |
| import java.util.Optional; |
| import java.util.regex.Pattern; |
| |
| /** |
| * Nested Diagnostic Context (NDC), aka. Thread Context Stack, resolver. |
| * |
| * <h3>Configuration</h3> |
| * |
| * <pre> |
| * config = [ pattern ] |
| * pattern = "pattern" -> string |
| * </pre> |
| * |
| * <h3>Examples</h3> |
| * |
| * Resolve all NDC values into a list: |
| * |
| * <pre> |
| * { |
| * "$resolver": "ndc" |
| * } |
| * </pre> |
| * |
| * Resolve all NDC values matching with the <tt>pattern</tt> regex: |
| * |
| * <pre> |
| * { |
| * "$resolver": "ndc", |
| * "pattern": "user(Role|Rank):\\w+" |
| * } |
| * </pre> |
| */ |
| final class ThreadContextStackResolver implements EventResolver { |
| |
| private final Pattern itemPattern; |
| |
| ThreadContextStackResolver(final TemplateResolverConfig config) { |
| this.itemPattern = Optional |
| .ofNullable(config.getString("pattern")) |
| .map(Pattern::compile) |
| .orElse(null); |
| } |
| |
| static String getName() { |
| return "ndc"; |
| } |
| |
| @Override |
| public boolean isResolvable(final LogEvent logEvent) { |
| final ThreadContext.ContextStack contextStack = logEvent.getContextStack(); |
| return contextStack.getDepth() > 0; |
| } |
| |
| @Override |
| public void resolve( |
| final LogEvent logEvent, |
| final JsonWriter jsonWriter) { |
| final ThreadContext.ContextStack contextStack = logEvent.getContextStack(); |
| if (contextStack.getDepth() == 0) { |
| jsonWriter.writeNull(); |
| return; |
| } |
| boolean arrayStarted = false; |
| for (final String contextStackItem : contextStack.asList()) { |
| final boolean matched = |
| itemPattern == null || |
| itemPattern.matcher(contextStackItem).matches(); |
| if (matched) { |
| if (arrayStarted) { |
| jsonWriter.writeSeparator(); |
| } else { |
| jsonWriter.writeArrayStart(); |
| arrayStarted = true; |
| } |
| jsonWriter.writeString(contextStackItem); |
| } |
| } |
| if (arrayStarted) { |
| jsonWriter.writeArrayEnd(); |
| } else { |
| jsonWriter.writeNull(); |
| } |
| } |
| |
| } |