Java regex failure in ActuatorSkipPatternProviderConfig while compiling actuator/management endpoints referencing other Spring properties

[chintanb]

Describe the bug
ActuatorSkipPatternProviderConfig fails to compile actuator endpoint values defined with reference to other properties.

If I try to override the health actuator endpoint with following value, application fails to start with spring-cloud-starter-sleuth version 2.2.3.RELEASE.

spring.cloud.discovery.health-check-url: /health${spring.application.instance_id}

Notice how it references other Spring property in order to generate unique health endpoint for each micro-service instance. This is just an example, the endpoint property value can reference other properties too.

The error stack trace is as follows.

Failed to load ApplicationContext
...
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sleuthSkipPatternProvider' defined in class path resource [org/springframework/cloud/sleuth/instrument/web/TraceWebAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.cloud.sleuth.instrument.web.SkipPatternProvider]: Factory method 'sleuthSkipPatternProvider' threw exception; nested exception is java.util.regex.PatternSyntaxException: Illegal repetition near index 8
/(health${spring.application.instance_id}|health${spring.application.instance_id}/.*|info|info/.*)
        ^
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:655)
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:483)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1338)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1177)
	at 
...
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.cloud.sleuth.instrument.web.SkipPatternProvider]: Factory method 'sleuthSkipPatternProvider' threw exception; nested exception is java.util.regex.PatternSyntaxException: Illegal repetition near index 8
/(health${spring.application.instance_id}|health${spring.application.instance_id}/.*|info|info/.*)
        ^
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185)
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:650)
	... 71 more
Caused by: java.util.regex.PatternSyntaxException: Illegal repetition near index 8
/(health${spring.application.instance_id}|health${spring.application.instance_id}/.*|info|info/.*)
        ^
	at java.util.regex.Pattern.error(Pattern.java:1957)
	at java.util.regex.Pattern.closure(Pattern.java:3159)
	at java.util.regex.Pattern.sequence(Pattern.java:2136)
	at java.util.regex.Pattern.expr(Pattern.java:1998)
	at java.util.regex.Pattern.group0(Pattern.java:2907)
	at java.util.regex.Pattern.sequence(Pattern.java:2053)
	at java.util.regex.Pattern.expr(Pattern.java:1998)
	at java.util.regex.Pattern.compile(Pattern.java:1698)
	at java.util.regex.Pattern.<init>(Pattern.java:1351)
	at java.util.regex.Pattern.compile(Pattern.java:1028)
	at org.springframework.cloud.sleuth.instrument.web.TraceWebAutoConfiguration$ActuatorSkipPatternProviderConfig.getEndpointsPatterns(TraceWebAutoConfiguration.java:144)
	at org.springframework.cloud.sleuth.instrument.web.TraceWebAutoConfiguration$ActuatorSkipPatternProviderConfig.lambda$skipPatternForActuatorEndpointsSamePort$0(TraceWebAutoConfiguration.java:193)
	at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
	at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1382)
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
	at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499)
	at org.springframework.cloud.sleuth.instrument.web.TraceWebAutoConfiguration.sleuthSkipPatternProvider(TraceWebAutoConfiguration.java:78)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
	... 72 more

Referencing other Spring properties in actuator/management endpoints is not uncommon so, I recommend enhancing regex compile / processing to support such values too.

Sample
Override health-check-url to something else that references other Spring property and start the application.
For example,
spring.cloud.discovery.health-check-url: /health${spring.application.instance_id}

Workaround
As a workaround, I set ignoreAutoConfiguredSkipPatterns=true. Which is ok for now, but I want to skip all other actuator and management endpoints so eventually I would like to revert it (set ignoreAutoConfiguredSkipPatterns to false).

[chintanb]

Thanks @marcingrzejszczak

[marcingrzejszczak]

No problem, please double check against the snapshots that things work fine

[chintanb]

I will and update you here.