Merge pull request #82 from newrelic/capture-full-trace

Capture full stack traces; add config support for unlimited trace size

Author: jtduffy

README.md

@@ -34,12 +34,17 @@ MDC data will be added to log events with a `context.` prefix to distinguish it
 collisions with New Relic specific context keys.
 
 ### Exception Stack Trace Size
+**Note:** The log extensions now have the ability to capture the entire stack trace - specifically any `caused by` sections.
+Prior versions of the extension only reported the trace for the thrown exception and ignored any nested `caused by` `Throwables`.
+
 You can configure the logging extension to control the max stack trace size for exceptions added to log events.
 
 Default max stack trace size is `300`. It is recommended that you do not exceed this value or data could be dropped or truncated as well as
 lead to higher log event ingest costs. Max stack trace size can be configured by environment variable (`NEW_RELIC_LOG_EXTENSION_MAX_STACK_SIZE=integer`)
 or system property (`-Dnewrelic.log_extension.max_stack_size=integer`).
 
+Explicitly setting this property to `0` will not impose a maximum size constraint on the stack trace size.
+
 ## Support
 
 Should you need assistance with New Relic products, you are in good hands with several diagnostic tools and support channels.

core/build.gradle.kts

@@ -12,6 +12,7 @@ configure<JavaPluginConvention> {
 }
 
 dependencies {
+    implementation("org.apache.commons:commons-lang3:3.13.0")
     testImplementation("org.junit.jupiter:junit-jupiter:5.6.2")
     // Allows for easy testing of values based on Environment Variables and System Properties
     testImplementation("com.github.stefanbirkner:system-lambda:1.2.1")

core/src/main/java/com/newrelic/logging/core/ExceptionUtil.java

@@ -5,32 +5,42 @@
 
 package com.newrelic.logging.core;
 
+import org.apache.commons.lang3.exception.ExceptionUtils;
+
+import java.util.Arrays;
+
 import static com.newrelic.logging.core.LogExtensionConfig.getMaxStackSize;
 
 public class ExceptionUtil {
     public static final int MAX_STACK_SIZE_DEFAULT = 300;
-    public static String getErrorStack(Throwable throwable) {
+
+    public static String getFullStackTrace(Throwable throwable) {
         if (throwable == null) {
             return null;
         }
 
-        StackTraceElement[] stack = throwable.getStackTrace();
-        return getErrorStack(stack);
-    }
-
-    public static String getErrorStack(StackTraceElement[] stack) {
-        return getErrorStack(stack, getMaxStackSize());
+        return getStackTraceStringFromFramesArray(ExceptionUtils.getStackFrames(throwable));
     }
 
-    public static String getErrorStack(StackTraceElement[] stack, Integer maxStackSize) {
-        if (stack == null || stack.length == 0) {
+    public static String transformLogbackStackTraceString(String trace) {
+        if (trace == null || trace.length() == 0) {
             return null;
         }
 
-        StringBuilder stackBuilder = new StringBuilder();
-        for(int i = 0; i < Math.min(maxStackSize, stack.length); i++) {
-            stackBuilder.append("  at ").append(stack[i].toString()).append("\n");
+        return getStackTraceStringFromFramesArray(trace.split("\n"));
+    }
+
+    private static String getStackTraceStringFromFramesArray(String[] frames) {
+        int maxStackSize = getMaxStackSize();
+
+        //We need to truncate the stacktrace based on the desired max stacktrace size, as well as remove the first line
+        //of the returned trace (the "message"), since this is already captured in the error.message attribute.
+        if (frames.length > maxStackSize) {
+            frames = Arrays.copyOfRange(frames, 1, maxStackSize + 1);
+        } else {
+            frames = Arrays.copyOfRange(frames, 1, frames.length);
         }
-        return stackBuilder.toString();
+
+        return String.join("\n", frames).replace("\tat", "  at") + "\n";
     }
 }

core/src/main/java/com/newrelic/logging/core/LogExtensionConfig.java

@@ -16,7 +16,8 @@ public class LogExtensionConfig {
     public static final boolean ADD_MDC_DEFAULT = false;
 
     /**
-     * Get an int representing the max stack size for errors that should be added to logs
+     * Get an int representing the max stack size for errors that should be added to logs. Explicitly setting the
+     * value to 0 will not impose a maximum size constraint on the stack trace size.
      * <p>
      * Precedence: Env var > Sys prop > Default
      *
@@ -25,14 +26,17 @@ public class LogExtensionConfig {
     public static int getMaxStackSize() {
         String envVar = System.getenv(MAX_STACK_SIZE_ENV_VAR);
         String sysProp = System.getProperty(MAX_STACK_SIZE_SYS_PROP);
+        int parsedValue;
 
         if (isInteger(envVar)) {
-            return Integer.parseInt(envVar);
+            parsedValue = Integer.parseInt(envVar);
         } else if (isInteger(sysProp)) {
-            return Integer.parseInt(sysProp);
+            parsedValue = Integer.parseInt(sysProp);
         } else {
-            return ExceptionUtil.MAX_STACK_SIZE_DEFAULT;
+            parsedValue = ExceptionUtil.MAX_STACK_SIZE_DEFAULT;
         }
+
+        return (parsedValue == 0 ? Integer.MAX_VALUE : parsedValue);
     }
 
     /**

core/src/test/java/com/newrelic/logging/core/LogExtensionConfigTest.java

@@ -20,6 +20,18 @@
 
 class LogExtensionConfigTest {
 
+    @Test
+    void getMaxStackSize_withValueOfZeroAndSetAsSysProp_returnsMaxInt() {
+        System.setProperty(MAX_STACK_SIZE_SYS_PROP, String.valueOf(0));
+        assertEquals(Integer.MAX_VALUE, LogExtensionConfig.getMaxStackSize());
+        System.clearProperty(MAX_STACK_SIZE_SYS_PROP);
+    }
+
+    @Test
+    void getMaxStackSize_withValueOfZeroAndSetAsEnvVar_returnsMaxInt() throws Exception {
+        assertEquals(Integer.MAX_VALUE, withEnvironmentVariable(MAX_STACK_SIZE_ENV_VAR, String.valueOf(0)).execute(LogExtensionConfig::getMaxStackSize));
+    }
+
     @Test
     void testGetMaxStackSizeDefault() {
         int actualSize = LogExtensionConfig.getMaxStackSize();