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9 | 9 | import java.lang.instrument.ClassFileTransformer; |
10 | 10 | import java.lang.instrument.IllegalClassFormatException; |
11 | 11 | import java.security.ProtectionDomain; |
| 12 | +import java.util.Set; |
| 13 | +import java.util.concurrent.ConcurrentHashMap; |
12 | 14 |
|
13 | 15 | /** |
14 | 16 | * @author msauer |
15 | 17 | */ |
16 | 18 | public class Transformer implements ClassFileTransformer { |
17 | 19 |
|
18 | 20 | private static final Logger logger = Logger.getLogger(Transformer.class); |
| 21 | + private static final String[] HARD_SKIPPED_PREFIXES = new String[]{ |
| 22 | + "de/marcelsauer/profiler/", |
| 23 | + "java/", |
| 24 | + "javax/", |
| 25 | + "jdk/", |
| 26 | + "sun/", |
| 27 | + "com/sun/", |
| 28 | + "org/slf4j/", |
| 29 | + "ch/qos/logback/", |
| 30 | + "org/apache/log4j/", |
| 31 | + "org/apache/logging/log4j/", |
| 32 | + "javassist/", |
| 33 | + "net/bytebuddy/", |
| 34 | + "org/objectweb/asm/", |
| 35 | + "cglib/", |
| 36 | + "org/springframework/cglib/" |
| 37 | + }; |
| 38 | + private static final int DEFAULT_TRANSFORM_FAILURE_THRESHOLD = 50; |
| 39 | + private static final long DEFAULT_TRANSFORM_FAILURE_WINDOW_MILLIS = 30_000L; |
| 40 | + private static final long DEFAULT_TRANSFORM_CIRCUIT_OPEN_MILLIS = 60_000L; |
| 41 | + |
19 | 42 | private final CombinedFilter combinedFilter; |
| 43 | + private final Set<String> permanentlySkippedClasses = ConcurrentHashMap.newKeySet(); |
| 44 | + private final Object transformCircuitLock = new Object(); |
| 45 | + private final int transformFailureThreshold; |
| 46 | + private final long transformFailureWindowMillis; |
| 47 | + private final long transformCircuitOpenMillis; |
| 48 | + |
| 49 | + private long transformFailureWindowStartMillis; |
| 50 | + private int transformFailuresInWindow; |
| 51 | + private long transformCircuitOpenUntilMillis; |
20 | 52 |
|
21 | 53 | Instrumenter instrumenter; |
22 | 54 |
|
23 | 55 | public Transformer(Config config) { |
| 56 | + this(config, |
| 57 | + DEFAULT_TRANSFORM_FAILURE_THRESHOLD, |
| 58 | + DEFAULT_TRANSFORM_FAILURE_WINDOW_MILLIS, |
| 59 | + DEFAULT_TRANSFORM_CIRCUIT_OPEN_MILLIS); |
| 60 | + } |
| 61 | + |
| 62 | + Transformer(Config config, int transformFailureThreshold, long transformFailureWindowMillis, long transformCircuitOpenMillis) { |
24 | 63 | this.instrumenter = new Instrumenter(new DefaultInstrumentationCallback()); |
25 | 64 | this.combinedFilter = new CombinedFilter(config); |
| 65 | + this.transformFailureThreshold = Math.max(1, transformFailureThreshold); |
| 66 | + this.transformFailureWindowMillis = Math.max(1_000L, transformFailureWindowMillis); |
| 67 | + this.transformCircuitOpenMillis = Math.max(1_000L, transformCircuitOpenMillis); |
26 | 68 | logger.debug("using transformer: " + Transformer.class.getName()); |
27 | 69 | } |
28 | 70 |
|
29 | 71 | public byte[] transform(ClassLoader loader, String className, Class klass, ProtectionDomain domain, byte[] byteCode) throws IllegalClassFormatException { |
30 | 72 | try { |
31 | | - if (loader == null) { |
| 73 | + if (loader == null || className == null) { |
32 | 74 | logger.debug(String.format("[skipping bootstrap class] '%s'.", className)); |
33 | 75 | return byteCode; |
34 | 76 | } |
35 | 77 |
|
| 78 | + if (isHardSkipped(className) || permanentlySkippedClasses.contains(className)) { |
| 79 | + return byteCode; |
| 80 | + } |
| 81 | + |
| 82 | + if (isTransformCircuitOpen()) { |
| 83 | + return byteCode; |
| 84 | + } |
| 85 | + |
36 | 86 | boolean shouldBeInstrumented = combinedFilter.matches(className); |
37 | | - if (shouldBeInstrumented) { |
38 | | - logger.debug(String.format("[instrumenting] '%s'.", className)); |
39 | | - byte[] transformed = this.instrumenter.instrument(className, loader); |
40 | | - // null means "skip transformation" per ClassFileTransformer contract |
41 | | - return transformed != null ? transformed : byteCode; |
| 87 | + if (!shouldBeInstrumented) { |
| 88 | + return byteCode; |
42 | 89 | } |
43 | | - return byteCode; |
| 90 | + |
| 91 | + logger.debug(String.format("[instrumenting] '%s'.", className)); |
| 92 | + byte[] transformed = this.instrumenter.instrument(className, loader); |
| 93 | + // null means "skip transformation" per ClassFileTransformer contract |
| 94 | + return transformed != null ? transformed : byteCode; |
44 | 95 | } catch (Throwable t) { |
| 96 | + if (className != null) { |
| 97 | + permanentlySkippedClasses.add(className); |
| 98 | + } |
| 99 | + registerTransformFailure(className, t); |
45 | 100 | // Never let any exception escape the transformer — the JVM JPLIS layer |
46 | 101 | // turns uncaught throwables into the ugly "!errorOutstanding" native assertion. |
47 | 102 | logger.warn(String.format("transform failed for '%s', returning original bytecode: %s", className, t.getMessage())); |
48 | 103 | return byteCode; |
49 | 104 | } |
50 | 105 | } |
51 | 106 |
|
| 107 | + private boolean isHardSkipped(String className) { |
| 108 | + for (String hardSkippedPrefix : HARD_SKIPPED_PREFIXES) { |
| 109 | + if (className.startsWith(hardSkippedPrefix)) { |
| 110 | + return true; |
| 111 | + } |
| 112 | + } |
| 113 | + return false; |
| 114 | + } |
| 115 | + |
| 116 | + protected long currentTimeMillis() { |
| 117 | + return System.currentTimeMillis(); |
| 118 | + } |
| 119 | + |
| 120 | + private boolean isTransformCircuitOpen() { |
| 121 | + synchronized (transformCircuitLock) { |
| 122 | + return currentTimeMillis() < transformCircuitOpenUntilMillis; |
| 123 | + } |
| 124 | + } |
| 125 | + |
| 126 | + private void registerTransformFailure(String className, Throwable throwable) { |
| 127 | + synchronized (transformCircuitLock) { |
| 128 | + long now = currentTimeMillis(); |
| 129 | + |
| 130 | + if (transformFailureWindowStartMillis == 0L |
| 131 | + || (now - transformFailureWindowStartMillis) > transformFailureWindowMillis) { |
| 132 | + transformFailureWindowStartMillis = now; |
| 133 | + transformFailuresInWindow = 0; |
| 134 | + } |
| 135 | + |
| 136 | + transformFailuresInWindow++; |
| 137 | + |
| 138 | + if (transformFailuresInWindow >= transformFailureThreshold) { |
| 139 | + transformCircuitOpenUntilMillis = now + transformCircuitOpenMillis; |
| 140 | + logger.warn(String.format( |
| 141 | + "transform circuit opened for %dms after %d failures in %dms window. latest class='%s', cause='%s'", |
| 142 | + transformCircuitOpenMillis, |
| 143 | + transformFailuresInWindow, |
| 144 | + transformFailureWindowMillis, |
| 145 | + className, |
| 146 | + throwable == null ? "n/a" : throwable.getClass().getSimpleName())); |
| 147 | + transformFailureWindowStartMillis = now; |
| 148 | + transformFailuresInWindow = 0; |
| 149 | + } |
| 150 | + } |
| 151 | + } |
| 152 | + |
52 | 153 | } |
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