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[🍒 7429] Fix Fingerprinter thread safety #7434

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merged 1 commit into from
Aug 14, 2024
Merged

[🍒 7429] Fix Fingerprinter thread safety #7434

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113 changes: 98 additions & 15 deletions dd-java-agent/agent-debugger/src/main/java/com/datadog/debugger/exception/Fingerprinter.java
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Original file line number Diff line number Diff line change
Expand Up @@ -4,33 +4,31 @@

import com.datadog.debugger.util.ClassNameFiltering;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/** Computes a fingerprint of an exception based on its stacktrace and exception type. */
public class Fingerprinter {
private static final Logger LOGGER = LoggerFactory.getLogger(Fingerprinter.class);
private static MessageDigest digest;

static {
try {
digest = MessageDigest.getInstance("SHA-256");
} catch (Throwable e) {
LOGGER.debug("Unable to find digest algorithm SHA-256", e);
}
}

// compute fingerprint of the Throwable based on the stacktrace and exception type
public static String fingerprint(Throwable t, ClassNameFiltering classNameFiltering) {
if (digest == null) {
return null;
}
t = getInnerMostThrowable(t);
if (t == null) {
LOGGER.debug("Unable to find root cause of exception");
return null;
}
Class<? extends Throwable> clazz = t.getClass();
MessageDigest digest;
try {
// need to create a new instance each time to make it thread safe
// Regarding performance, see the results of micro-benchmarks at the end of the file
digest = MessageDigest.getInstance("SHA-256");
} catch (NoSuchAlgorithmException e) {
LOGGER.debug("Unable to find digest algorithm SHA-256", e);
return null;
}
String typeName = clazz.getTypeName();
digest.update(typeName.getBytes());
StackTraceElement[] stackTrace = t.getStackTrace();
Expand All @@ -45,11 +43,14 @@ public static String fingerprint(Throwable t, ClassNameFiltering classNameFilter
}

public static String fingerprint(StackTraceElement element) {
if (digest == null) {
try {
MessageDigest digest = MessageDigest.getInstance("SHA-256");
digest.update(element.toString().getBytes());
return bytesToHex(digest.digest());
} catch (NoSuchAlgorithmException e) {
LOGGER.debug("Unable to find digest algorithm SHA-256", e);
return null;
}
digest.update(element.toString().getBytes());
return bytesToHex(digest.digest());
}

// convert byte[] to hex string
Expand All @@ -61,3 +62,85 @@ private static String bytesToHex(byte[] bytes) {
return result.toString();
}
}

/*
Micro benchmark results:
jdk8 arm64:
Benchmark Mode Cnt Score Error Units
MessageDigestBenchmark.md5NewInstance avgt 5 4.974 ± 0.069 us/op
MessageDigestBenchmark.md5ReuseInstance avgt 5 4.787 ± 0.137 us/op
MessageDigestBenchmark.sha1NewInstance avgt 5 6.131 ± 0.038 us/op
MessageDigestBenchmark.sha1ReuseInstance avgt 5 6.088 ± 0.016 us/op
MessageDigestBenchmark.sha256NewInstance avgt 5 7.090 ± 0.091 us/op
MessageDigestBenchmark.sha256ReuseInstance avgt 5 7.048 ± 0.132 us/op

jdk11 arm64:
Benchmark Mode Cnt Score Error Units
MessageDigestBenchmark.md5NewInstance avgt 5 5.258 ± 0.166 us/op
MessageDigestBenchmark.md5ReuseInstance avgt 5 5.196 ± 0.053 us/op
MessageDigestBenchmark.sha1NewInstance avgt 5 6.639 ± 0.136 us/op
MessageDigestBenchmark.sha1ReuseInstance avgt 5 6.522 ± 0.096 us/op
MessageDigestBenchmark.sha256NewInstance avgt 5 7.600 ± 0.130 us/op
MessageDigestBenchmark.sha256ReuseInstance avgt 5 7.605 ± 0.115 us/op

jdk17 arm64:
Benchmark Mode Cnt Score Error Units
MessageDigestBenchmark.md5NewInstance avgt 5 3.749 ± 0.054 us/op
MessageDigestBenchmark.md5ReuseInstance avgt 5 3.713 ± 0.061 us/op
MessageDigestBenchmark.sha1NewInstance avgt 5 5.708 ± 0.079 us/op
MessageDigestBenchmark.sha1ReuseInstance avgt 5 5.646 ± 0.070 us/op
MessageDigestBenchmark.sha256NewInstance avgt 5 8.668 ± 0.073 us/op
MessageDigestBenchmark.sha256ReuseInstance avgt 5 8.651 ± 0.131 us/op

jdk21 arm64:
Benchmark Mode Cnt Score Error Units
MessageDigestBenchmark.md5NewInstance avgt 5 2.702 ± 0.023 us/op
MessageDigestBenchmark.md5ReuseInstance avgt 5 2.675 ± 0.018 us/op
MessageDigestBenchmark.sha1NewInstance avgt 5 0.818 ± 0.005 us/op
MessageDigestBenchmark.sha1ReuseInstance avgt 5 0.798 ± 0.035 us/op
MessageDigestBenchmark.sha256NewInstance avgt 5 0.814 ± 0.018 us/op
MessageDigestBenchmark.sha256ReuseInstance avgt 5 0.792 ± 0.017 us/op

jdk21 arm64 -XX:+UnlockDiagnosticVMOptions -XX:-UseSHA1Intrinsics -XX:-UseSHA256Intrinsics
Benchmark Mode Cnt Score Error Units
MessageDigestBenchmark.sha1NewInstance avgt 5 5.030 ± 0.041 us/op
MessageDigestBenchmark.sha1ReuseInstance avgt 5 5.121 ± 0.090 us/op
MessageDigestBenchmark.sha256NewInstance avgt 5 7.677 ± 0.089 us/op
MessageDigestBenchmark.sha256ReuseInstance avgt 5 7.627 ± 0.065 us/op

jdk8 x86_64:
Benchmark Mode Cnt Score Error Units
MessageDigestBenchmark.md5NewInstance avgt 5 4.435 ± 0.166 us/op
MessageDigestBenchmark.md5ReuseInstance avgt 5 4.364 ± 0.206 us/op
MessageDigestBenchmark.sha1NewInstance avgt 5 5.966 ± 0.224 us/op
MessageDigestBenchmark.sha1ReuseInstance avgt 5 5.901 ± 0.349 us/op
MessageDigestBenchmark.sha256NewInstance avgt 5 9.220 ± 0.667 us/op
MessageDigestBenchmark.sha256ReuseInstance avgt 5 9.162 ± 0.860 us/op

jdk11 x86_64:
Benchmark Mode Cnt Score Error Units
MessageDigestBenchmark.md5NewInstance avgt 5 4.716 ± 0.233 us/op
MessageDigestBenchmark.md5ReuseInstance avgt 5 4.662 ± 0.258 us/op
MessageDigestBenchmark.sha1NewInstance avgt 5 1.444 ± 0.066 us/op
MessageDigestBenchmark.sha1ReuseInstance avgt 5 1.396 ± 0.060 us/op
MessageDigestBenchmark.sha256NewInstance avgt 5 1.533 ± 0.054 us/op
MessageDigestBenchmark.sha256ReuseInstance avgt 5 1.494 ± 0.052 us/op

jdk17 x86_64:
Benchmark Mode Cnt Score Error Units
MessageDigestBenchmark.md5NewInstance avgt 5 2.852 ± 0.191 us/op
MessageDigestBenchmark.md5ReuseInstance avgt 5 2.816 ± 0.086 us/op
MessageDigestBenchmark.sha1NewInstance avgt 5 1.329 ± 0.051 us/op
MessageDigestBenchmark.sha1ReuseInstance avgt 5 1.363 ± 0.238 us/op
MessageDigestBenchmark.sha256NewInstance avgt 5 1.397 ± 0.133 us/op
MessageDigestBenchmark.sha256ReuseInstance avgt 5 1.391 ± 0.047 us/op

jdk22 x86_64:
Benchmark Mode Cnt Score Error Units
MessageDigestBenchmark.md5NewInstance avgt 5 4.757 ± 0.179 us/op
MessageDigestBenchmark.md5ReuseInstance avgt 5 4.689 ± 0.300 us/op
MessageDigestBenchmark.sha1NewInstance avgt 5 1.460 ± 0.049 us/op
MessageDigestBenchmark.sha1ReuseInstance avgt 5 1.423 ± 0.066 us/op
MessageDigestBenchmark.sha256NewInstance avgt 5 1.567 ± 0.123 us/op
MessageDigestBenchmark.sha256ReuseInstance avgt 5 1.521 ± 0.084 us/op
*/