Ankur Mhatre
86246dc860
configuration-properties/ @ConfigurationProperties vs @Value on Spring Boot 4.1.1. The relaxed-binding matrix is generated by binding each spelling rather than transcribed, and re-checked against real processes -- the in-process probe was wrong twice before it was right. Records the three findings that came out of it: @Value does get relaxed resolution inside Spring Boot (Boot attaches ConfigurationPropertySources), the configuration processor silently stops generating metadata on JDK 23+ when declared as a plain dependency, and @Valid is not what makes nested constraints run. profiles-and-config/ Precedence, profiles, spring.config.import and config trees. /precedence reports every source holding a property in rank order with file and line, which turns "my profile file had no effect" into a two-line answer. Also pins the counterintuitive one: an imported file outranks the file that imported it. spring-aop/ Designators, proxy types, and aspects that do not fire. One advice per supported designator so the reference table is generated from real matches; all fourteen unsupported designators fed to the parser. Two corrections to the reference documentation: unsupported designators throw UnsupportedPointcutPrimitiveException (extends RuntimeException, not IllegalArgumentException), and spring-boot-starter-aop was renamed to spring-boot-starter-aspectj in Boot 4. 19 contract tests across the three modules, 15 captured transcripts, all regenerated by scripts/run-all.sh. Verified on Spring Boot 4.1.1, Spring Framework 7.0.9, JDK 25.0.4.1. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Gip4srpzMwjgoba6uEfbr5
46 lines
2.0 KiB
Plaintext
46 lines
2.0 KiB
Plaintext
== what Kubernetes actually mounts ==
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$ find /tmp/demo-configmap /tmp/demo-secret -type f | sort
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<configmap-mount>/demo.datasource-url
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<configmap-mount>/demo.greeting
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<configmap-mount>/demo.pool-size
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<configmap-mount>/demo/nested/value
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<secret-mount>/demo.api-key
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$ cat <configmap-mount>/demo.greeting; echo
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from-configmap-volume
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Each file holds a bare value with no trailing newline and no key. There is no
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properties syntax to parse -- the filename is the key.
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== importing it ==
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$ java -jar target/profiles-and-config-1.0.0.jar \
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--spring.config.import=configtree:/tmp/demo-configmap/,configtree:/tmp/demo-secret/
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active profiles : (none)
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effective value : from-configmap-volume
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1. from-configmap-volume <- ConfigTreePropertySource {name='Config tree '/tmp/demo-configmap''}
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2. from-application-yaml <- 'file application.yaml' via location 'optional:classpath:/''}
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holders that lost: 1
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demo.pool-size = 25
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demo.nested.value = from-nested-directory
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demo.api-key = sk_live_not_a_real_key
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A directory under the mount becomes a nested property: demo/nested/value is
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demo.nested.value. That is how a ConfigMap with slashes in its keys arrives.
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== the part that surprises people ==
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An imported config tree outranks application.yaml, but it is still config data,
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so it still loses to an environment variable:
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active profiles : (none)
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effective value : from-environment-variable
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1. from-environment-variable <- OriginAwareSystemEnvironmentPropertySource {name='systemEnvironment'}
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2. from-configmap-volume <- ConfigTreePropertySource {name='Config tree '/tmp/demo-configmap''}
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3. from-application-yaml <- 'file application.yaml' via location 'optional:classpath:/''}
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holders that lost: 2
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There is also no such thing as a profile-specific config tree. There is no
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<mount>-prod directory convention; a per-environment ConfigMap is a different mount
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chosen by the deployment, not by spring.profiles.active.
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