Add stackhash field to JsonEncoder (on by default)

The StackHasher used includes all the common stack element filtering such that it should produce a relatively stable hash.

Author: rob-bygrave

src/main/java/io/avaje/logback/encoder/FilterBuilder.java

@@ -40,6 +40,15 @@ public StackElementFilter.Builder byPattern(List<Pattern> excludes) {
     return this;
   }
 
+  @Override
+  public StackElementFilter.Builder allFilters() {
+    generated();
+    reflectiveInvocation();
+    jdkInternals();
+    spring();
+    return this;
+  }
+
   @Override
   public StackElementFilter build() {
     if (filters.isEmpty()) {

src/main/java/io/avaje/logback/encoder/JsonEncoder.java

@@ -9,6 +9,8 @@
 
 import ch.qos.logback.classic.pattern.ThrowableHandlingConverter;
 import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.classic.spi.IThrowableProxy;
+import ch.qos.logback.classic.spi.ThrowableProxy;
 import ch.qos.logback.core.encoder.EncoderBase;
 import io.avaje.json.PropertyNames;
 import io.avaje.json.simple.SimpleMapper;
@@ -20,6 +22,7 @@ public final class JsonEncoder extends EncoderBase<ILoggingEvent> {
   private final JsonStream json;
   private final Map<String, String> customFieldsMap = new HashMap<>();
   private final PropertyNames properties;
+  private final StackHasher stackHasher;
   private ThrowableHandlingConverter throwableConverter = new ShortenedThrowableConverter();
 
   private DateTimeFormatter formatter;
@@ -29,12 +32,14 @@ public final class JsonEncoder extends EncoderBase<ILoggingEvent> {
   private int fieldExtra;
   private String component;
   private String environment;
+  private boolean includeStackHash = true;
 
   public JsonEncoder() {
     this.json = JsonStream.builder().build();
-    this.properties = json.properties("component", "env", "timestamp", "level", "logger", "message", "thread", "stacktrace");
+    this.properties = json.properties("component", "env", "timestamp", "level", "logger", "message", "thread", "stackhash", "stacktrace");
     this.component = System.getenv("COMPONENT");
     this.environment = System.getenv("ENVIRONMENT");
+    this.stackHasher = new StackHasher(StackElementFilter.builder().allFilters().build());
   }
 
   @Override
@@ -96,7 +101,15 @@ public byte[] encode(ILoggingEvent event) {
       writer.name(6);
       writer.value(threadName);
       if (!stackTraceBody.isEmpty()) {
-        writer.name(7);
+        if (includeStackHash) {
+          IThrowableProxy throwableProxy = event.getThrowableProxy();
+          if (throwableProxy instanceof ThrowableProxy) {
+            String hash = stackHasher.hexHash(((ThrowableProxy) throwableProxy).getThrowable());
+            writer.name(7);
+            writer.value(hash);
+          }
+        }
+        writer.name(8);
         writer.value(stackTraceBody);
       }
       customFieldsMap.forEach((k, v) -> {
@@ -113,6 +126,10 @@ public byte[] encode(ILoggingEvent event) {
     return outputStream.toByteArray();
   }
 
+  public void setIncludeStackHash(boolean includeStackHash) {
+    this.includeStackHash = includeStackHash;
+  }
+
   public void setComponent(String component) {
     this.component = component;
   }

src/main/java/io/avaje/logback/encoder/StackElementFilter.java

@@ -101,9 +101,15 @@ interface Builder {
      */
     Builder byPattern(List<Pattern> excludes);
 
+    /**
+     * Include all the standard filters generated, reflective invocation, jdk internals and spring.
+     */
+    Builder allFilters();
+
     /**
      * Build and return the StackElementFilter with the given options.
      */
     StackElementFilter build();
+
   }
 }

src/test/java/io/avaje/logback/encoder/JsonEncoderTest.java

@@ -90,13 +90,37 @@ void throwable_usingConverter() {
 
         JsonEncoder encoder = new JsonEncoder();
         encoder.setThrowableConverter(converter);
+        encoder.setIncludeStackHash(false);
         encoder.start();
 
         byte[] bytes = encoder.encode(createLogEvent(createThrowable()));
         SimpleMapper simpleMapper = SimpleMapper.builder().build();
         Map<String, Object> asMap = simpleMapper.map().fromJson(bytes);
 
         assertThat((String)asMap.get("stacktrace")).startsWith("j.l.NullPointerException: ");
+        assertThat(asMap).doesNotContainKey("stackhash");
+    }
+
+    @Test
+    void throwable_usingConverter_includeStackHash() {
+        final TrimPackageAbbreviator trimPackages = new TrimPackageAbbreviator();
+        trimPackages.setTargetLength(10);
+
+        final ShortenedThrowableConverter converter = new ShortenedThrowableConverter();
+        converter.setMaxDepthPerThrowable(3);
+        converter.setClassNameAbbreviator(trimPackages);
+
+        JsonEncoder encoder = new JsonEncoder();
+        encoder.setThrowableConverter(converter);
+        encoder.setIncludeStackHash(true);
+        encoder.start();
+
+        byte[] bytes = encoder.encode(createLogEvent(createThrowable()));
+        SimpleMapper simpleMapper = SimpleMapper.builder().build();
+        Map<String, Object> asMap = simpleMapper.map().fromJson(bytes);
+
+        assertThat((String)asMap.get("stacktrace")).startsWith("j.l.NullPointerException: ");
+        assertThat((String)asMap.get("stackhash")).isEqualTo("2a4a23a6");
     }
 
     @Test