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Add opt-in correlation fields to Logback and Log4j2 text patterns #13277
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| Original file line number | Diff line number | Diff line change | ||||
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| @@ -0,0 +1,237 @@ | ||||||
| package datadog.trace.bootstrap.instrumentation.log; | ||||||
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| /** Adds missing MDC converters after the first complete field of a text logging pattern. */ | ||||||
| public final class LogPatternInjector { | ||||||
| public static final int SERVICE = 1; | ||||||
| public static final int TRACE_ID = 2; | ||||||
| public static final int SPAN_ID = 4; | ||||||
| public static final int ALL = SERVICE | TRACE_ID | SPAN_ID; | ||||||
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| private LogPatternInjector() {} | ||||||
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| /** Uses fields discovered by Logback's native parser. */ | ||||||
| public static String injectLogback(String pattern, int presentFields) { | ||||||
| return inject(pattern, presentFields, true); | ||||||
| } | ||||||
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|
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| /** MDC syntax capabilities of the supported Log4j releases. */ | ||||||
| public enum Format { | ||||||
| LOG4J2_LEGACY(false), | ||||||
| LOG4J2(true); | ||||||
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| private final boolean keyLists; | ||||||
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| Format(boolean keyLists) { | ||||||
| this.keyLists = keyLists; | ||||||
| } | ||||||
| } | ||||||
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| /** Recognizes MDC converters using the syntax supported by the running framework. */ | ||||||
| public static String injectLog4j(String pattern, Format format) { | ||||||
| if (pattern == null || pattern.isEmpty()) { | ||||||
| return pattern; | ||||||
| } | ||||||
| return inject(pattern, fields(pattern, 0, pattern.length(), format), false); | ||||||
| } | ||||||
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| private static int field(String key) { | ||||||
| if ("dd.service".equals(key)) { | ||||||
| return SERVICE; | ||||||
| } | ||||||
| if ("dd.trace_id".equals(key)) { | ||||||
| return TRACE_ID; | ||||||
| } | ||||||
| return "dd.span_id".equals(key) ? SPAN_ID : 0; | ||||||
| } | ||||||
|
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| private static int fields(String pattern, int start, int end, Format format) { | ||||||
| int found = 0; | ||||||
| for (int i = start; i < end; i++) { | ||||||
| if (pattern.charAt(i) != '%') { | ||||||
| continue; | ||||||
| } | ||||||
| i++; | ||||||
| if (i < end && pattern.charAt(i) == '%') { | ||||||
| continue; | ||||||
| } | ||||||
| while (i < end | ||||||
| && (pattern.charAt(i) == '-' | ||||||
| || pattern.charAt(i) == '.' | ||||||
| || Character.isDigit(pattern.charAt(i)))) { | ||||||
| i++; | ||||||
| } | ||||||
| int nameStart = i; | ||||||
| while (i < end && Character.isLetter(pattern.charAt(i))) { | ||||||
| i++; | ||||||
| } | ||||||
| String name = pattern.substring(nameStart, i); | ||||||
| boolean mdc = "X".equals(name) || "mdc".equals(name) || "MDC".equals(name); | ||||||
| boolean firstOption = true; | ||||||
| if (mdc && (i == end || pattern.charAt(i) != '{')) { | ||||||
| return ALL; | ||||||
| } | ||||||
| while (i < end && pattern.charAt(i) == '{') { | ||||||
| int close = optionEnd(pattern, i, end); | ||||||
| if (close < 0) { | ||||||
| return ALL; // Leave malformed patterns to the framework's validation. | ||||||
| } | ||||||
| if (mdc && firstOption) { | ||||||
| String keys = pattern.substring(i + 1, close); | ||||||
| if (format.keyLists && keys.indexOf(',') > 0) { | ||||||
| for (String key : keys.split(",")) { | ||||||
| found |= field(key.trim()); | ||||||
| } | ||||||
| } else { | ||||||
| found |= field(keys); | ||||||
| } | ||||||
| } else if (firstOption && isComposite(name)) { | ||||||
| found |= fields(pattern, i + 1, close, format); | ||||||
| } | ||||||
| firstOption = false; | ||||||
| i = close + 1; | ||||||
| } | ||||||
| i--; | ||||||
| } | ||||||
| return found; | ||||||
| } | ||||||
|
|
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| private static boolean isComposite(String name) { | ||||||
| return "style".equals(name) | ||||||
| || "highlight".equals(name) | ||||||
|
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When a supported Log4j pattern wraps an existing correlation converter in Useful? React with 👍 / 👎. |
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| || "replace".equals(name) | ||||||
| || "notEmpty".equals(name) | ||||||
| || "varsNotEmpty".equals(name) | ||||||
| || "variablesNotEmpty".equals(name) | ||||||
| || "equals".equals(name) | ||||||
| || "equalsIgnoreCase".equals(name) | ||||||
| || "maxLen".equals(name) | ||||||
| || "enc".equals(name) | ||||||
| || "encode".equals(name); | ||||||
| } | ||||||
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| private static int optionEnd(String pattern, int start, int end) { | ||||||
| int depth = 1; | ||||||
| for (int i = start + 1; i < end; i++) { | ||||||
| char c = pattern.charAt(i); | ||||||
| if (c == '{') { | ||||||
| depth++; | ||||||
| } else if (c == '}' && --depth == 0) { | ||||||
| return i; | ||||||
| } | ||||||
| } | ||||||
| return -1; | ||||||
| } | ||||||
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| private static boolean isLineBreak(String pattern, int i, boolean logback) { | ||||||
| return pattern.startsWith("%n", i) | ||||||
| && (logback || i + 2 == pattern.length() || !Character.isLetter(pattern.charAt(i + 2))); | ||||||
| } | ||||||
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| private static String inject(String pattern, int presentFields, boolean logback) { | ||||||
| if (pattern == null || pattern.isEmpty() || presentFields == ALL) { | ||||||
| return pattern; | ||||||
| } | ||||||
| // Preserve the first complete field, including date options and presentation wrappers. | ||||||
| int insertion = pattern.length(); | ||||||
| int optionsDepth = 0; | ||||||
| int compositeDepth = 0; | ||||||
| int bracketDepth = 0; | ||||||
| char quote = 0; | ||||||
| boolean fieldStarted = false; | ||||||
| for (int i = 0; i < pattern.length(); i++) { | ||||||
| char c = pattern.charAt(i); | ||||||
| if (c == '\\' && logback) { | ||||||
| fieldStarted = true; | ||||||
| i++; | ||||||
| continue; | ||||||
| } | ||||||
| if (!logback && c == '%' && i + 1 < pattern.length() && pattern.charAt(i + 1) == '%') { | ||||||
| fieldStarted = true; | ||||||
| i++; | ||||||
| continue; | ||||||
| } | ||||||
| if (optionsDepth > 0) { | ||||||
| if (quote != 0) { | ||||||
| if (c == quote) { | ||||||
| quote = 0; | ||||||
| } | ||||||
| } else if (c == '\'' || c == '"') { | ||||||
|
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With injection enabled, the valid Log4j2 pattern
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| quote = c; | ||||||
| } else if (c == '{') { | ||||||
| optionsDepth++; | ||||||
| } else if (c == '}') { | ||||||
| optionsDepth--; | ||||||
| } | ||||||
| continue; | ||||||
| } | ||||||
| if (c == '{') { | ||||||
| optionsDepth++; | ||||||
| } else if (logback && c == '(') { | ||||||
| compositeDepth++; | ||||||
| } else if (logback && c == ')' && compositeDepth > 0) { | ||||||
| compositeDepth--; | ||||||
| } else if (compositeDepth == 0 && c == '[') { | ||||||
| bracketDepth++; | ||||||
| } else if (compositeDepth == 0 && c == ']' && bracketDepth > 0) { | ||||||
| bracketDepth--; | ||||||
| } | ||||||
| if (compositeDepth == 0 && fieldStarted) { | ||||||
| if (isLineBreak(pattern, i, logback) || c == '\n' || c == '\r') { | ||||||
| insertion = i; | ||||||
| break; | ||||||
| } | ||||||
| if (bracketDepth == 0 && (Character.isWhitespace(c) || c == '|' || c == ',' || c == ';')) { | ||||||
| insertion = i; | ||||||
| // Keep the original separator before the new fields, including delimited logs. | ||||||
| while (insertion < pattern.length() | ||||||
| && Character.isWhitespace(pattern.charAt(insertion)) | ||||||
| && pattern.charAt(insertion) != '\n' | ||||||
| && pattern.charAt(insertion) != '\r') { | ||||||
| insertion++; | ||||||
| } | ||||||
| if (insertion < pattern.length() | ||||||
| && (pattern.charAt(insertion) == '|' | ||||||
| || pattern.charAt(insertion) == ',' | ||||||
| || pattern.charAt(insertion) == ';')) { | ||||||
| insertion++; | ||||||
| while (insertion < pattern.length() | ||||||
| && Character.isWhitespace(pattern.charAt(insertion)) | ||||||
| && pattern.charAt(insertion) != '\n' | ||||||
| && pattern.charAt(insertion) != '\r') { | ||||||
| insertion++; | ||||||
| } | ||||||
| } | ||||||
| break; | ||||||
| } | ||||||
| } | ||||||
| fieldStarted |= !Character.isWhitespace(c); | ||||||
| } | ||||||
| StringBuilder result = new StringBuilder(); | ||||||
| result.append(pattern, 0, insertion); | ||||||
| if (insertion > 0) { | ||||||
| char previous = pattern.charAt(insertion - 1); | ||||||
| if (!Character.isWhitespace(previous) | ||||||
| && previous != '|' | ||||||
| && previous != ',' | ||||||
| && previous != ';') { | ||||||
| result.append(' '); | ||||||
| } | ||||||
| } | ||||||
| if ((presentFields & SERVICE) == 0) { | ||||||
| result.append("dd.service=%X{dd.service} "); | ||||||
| } | ||||||
| if ((presentFields & TRACE_ID) == 0) { | ||||||
| result.append("dd.trace_id=%X{dd.trace_id} "); | ||||||
| } | ||||||
| if ((presentFields & SPAN_ID) == 0) { | ||||||
| result.append("dd.span_id=%X{dd.span_id} "); | ||||||
| } | ||||||
| if (insertion == pattern.length() | ||||||
| || isLineBreak(pattern, insertion, logback) | ||||||
| || pattern.charAt(insertion) == '\n' | ||||||
| || pattern.charAt(insertion) == '\r') { | ||||||
| result.setLength(result.length() - 1); | ||||||
| } | ||||||
| return result.append(pattern, insertion, pattern.length()).toString(); | ||||||
| } | ||||||
| } | ||||||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,74 @@ | ||
| package datadog.trace.instrumentation.log4j2; | ||
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| import static datadog.trace.agent.tooling.bytebuddy.matcher.ClassLoaderMatchers.hasClassNamed; | ||
| import static datadog.trace.bootstrap.instrumentation.api.AgentTracer.traceConfig; | ||
| import static java.util.Collections.singletonMap; | ||
| import static net.bytebuddy.matcher.ElementMatchers.isConstructor; | ||
| import static net.bytebuddy.matcher.ElementMatchers.not; | ||
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| import com.google.auto.service.AutoService; | ||
| import datadog.trace.agent.tooling.Instrumenter; | ||
| import datadog.trace.agent.tooling.InstrumenterModule; | ||
| import datadog.trace.api.Config; | ||
| import java.util.HashMap; | ||
| import java.util.Map; | ||
| import net.bytebuddy.asm.Advice; | ||
| import net.bytebuddy.matcher.ElementMatcher; | ||
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|
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| /** Provides the service field on versions predating Log4j2's ContextDataInjector. */ | ||
| @AutoService(InstrumenterModule.class) | ||
| public class LogEventServiceInstrumentation extends InstrumenterModule.Tracing | ||
| implements Instrumenter.ForSingleType, Instrumenter.HasMethodAdvice { | ||
| public LogEventServiceInstrumentation() { | ||
| super("log4j", "log4j-2"); | ||
| } | ||
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| @Override | ||
| protected boolean defaultEnabled() { | ||
| return Config.get().isLogPatternInject(); | ||
| } | ||
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| @Override | ||
| public ElementMatcher.Junction<ClassLoader> classLoaderMatcher() { | ||
| return not(hasClassNamed("org.apache.logging.log4j.core.impl.ContextDataInjectorFactory")); | ||
| } | ||
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| @Override | ||
| public String instrumentedType() { | ||
| return "org.apache.logging.log4j.core.impl.Log4jLogEvent"; | ||
|
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On Log4j2 versions before 2.7, AsyncLogger delivers RingBufferLogEvent instances directly to appenders, bypassing the Log4jLogEvent constructors instrumented here. The legacy ThreadContext updater supplies only trace/span IDs, and the newer context-data injector is unavailable. Consequently, enabling pattern injection leaves the added service field empty despite a configured service name. Service enrichment must also cover asynchronous event population. React: 👍 useful · 👎 wrong · 😕 unclear · 👀 right, but not acting on it What each reaction means
🤖 Bits Code Review · Open Bits AI session There was a problem hiding this comment.
When Log4j 2.0–2.6 is configured with Useful? React with 👍 / 👎. |
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| } | ||
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| @Override | ||
| public String muzzleDirective() { | ||
| return "default"; | ||
| } | ||
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| @Override | ||
| public void methodAdvice(MethodTransformer transformer) { | ||
| transformer.applyAdvice(isConstructor(), getClass().getName() + "$ServiceAdvice"); | ||
| } | ||
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| public static class ServiceAdvice { | ||
| @Advice.OnMethodExit(suppress = Throwable.class) | ||
| public static void onExit( | ||
| @Advice.FieldValue(value = "contextMap", readOnly = false) Map<String, String> context) { | ||
| Config config = Config.get(); | ||
| if (!config.isLogPatternInject() | ||
| || !traceConfig().isLogsInjectionEnabled() | ||
| || (context != null && context.containsKey("dd.service"))) { | ||
| return; | ||
| } | ||
| String service = config.getServiceName(); | ||
| if (service == null || service.isEmpty()) { | ||
| return; | ||
| } | ||
| if (context == null || context.isEmpty()) { | ||
| context = singletonMap("dd.service", service); | ||
| } else { | ||
| Map<String, String> copy = new HashMap<>(context); | ||
| copy.put("dd.service", service); | ||
| context = copy; | ||
| } | ||
| } | ||
| } | ||
| } | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,26 @@ | ||
| package datadog.trace.instrumentation.log4j2; | ||
|
|
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| import datadog.trace.api.Config; | ||
| import datadog.trace.bootstrap.instrumentation.log.LogPatternInjector; | ||
| import net.bytebuddy.asm.Advice; | ||
| import org.apache.logging.log4j.core.layout.PatternLayout; | ||
| import org.apache.logging.log4j.core.pattern.MdcPatternConverter; | ||
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| /** Rewrites the event pattern before Log4j compiles its converters. */ | ||
| public class PatternLayoutConstructorAdvice { | ||
| @Advice.OnMethodEnter(suppress = Throwable.class) | ||
| public static void onEnter(@Advice.Argument(value = 2, readOnly = false) String pattern) { | ||
| if (Config.get().isLogPatternInject()) { | ||
| LogPatternInjector.Format format = LogPatternInjector.Format.LOG4J2; | ||
| try { | ||
| // Early 2.x treats a comma-separated option as a single MDC key. | ||
| MdcPatternConverter.class.getDeclaredField("keys"); | ||
| } catch (NoSuchFieldException legacyVersion) { | ||
| format = LogPatternInjector.Format.LOG4J2_LEGACY; | ||
| } | ||
| pattern = | ||
| LogPatternInjector.injectLog4j( | ||
| pattern == null ? PatternLayout.DEFAULT_CONVERSION_PATTERN : pattern, format); | ||
| } | ||
| } | ||
| } |
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The composite list omits Log4j2's built-in color wrappers and
maxLengthalias, so existing MDC converters inside them are missed. For example,%cyan{%X{dd.trace_id}} %m%ngains a duplicate trace ID, while%blue{%X} %m%ngains all three fields despite already printing the entire MDC. Recognize these wrappers to preserve the promise to add only missing fields.React: 👍 useful · 👎 wrong · 😕 unclear · 👀 right, but not acting on it
What each reaction means
🤖 Bits Code Review · Open Bits AI session