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
67 lines
3.4 KiB
Bash
Executable File
67 lines
3.4 KiB
Bash
Executable File
#!/usr/bin/env bash
|
|
# Config trees: what a Kubernetes ConfigMap or Secret actually looks like to Spring Boot.
|
|
#
|
|
# A ConfigMap mounted as a volume is not a properties file. Kubernetes writes one file per
|
|
# key, named after the key, containing only the value. `configtree:` is the loader that reads
|
|
# that shape. This script builds the same directory layout on disk, so the demonstration is
|
|
# the real mechanism rather than a description of it.
|
|
set -euo pipefail
|
|
set +m
|
|
cd "$(dirname "$0")/.."
|
|
source scripts/env.sh
|
|
|
|
TREE="${TMPDIR:-/tmp}/demo-configmap"
|
|
SECRET="${TMPDIR:-/tmp}/demo-secret"
|
|
rm -rf "$TREE" "$SECRET"; mkdir -p "$TREE" "$SECRET"
|
|
|
|
# Exactly what `kubectl create configmap demo --from-literal=demo.greeting=...` produces
|
|
# once mounted: one file per key, the filename IS the property name.
|
|
printf 'from-configmap-volume' > "$TREE/demo.greeting"
|
|
printf 'jdbc:postgresql://configmap-db:5432/o' > "$TREE/demo.datasource-url"
|
|
printf '25' > "$TREE/demo.pool-size"
|
|
# Nested keys use a directory per level, or a dotted filename. Both work.
|
|
mkdir -p "$TREE/demo/nested"
|
|
printf 'from-nested-directory' > "$TREE/demo/nested/value"
|
|
# A Secret mount looks identical; only the permissions differ.
|
|
printf 'sk_live_not_a_real_key' > "$SECRET/demo.api-key"
|
|
|
|
{
|
|
echo "== what Kubernetes actually mounts =="
|
|
echo "\$ find $TREE $SECRET -type f | sort"
|
|
find "$TREE" "$SECRET" -type f | sort | sed "s|$TREE|<configmap-mount>|;s|$SECRET|<secret-mount>|"
|
|
echo
|
|
echo "\$ cat <configmap-mount>/demo.greeting; echo"
|
|
cat "$TREE/demo.greeting"; echo
|
|
echo
|
|
echo "Each file holds a bare value with no trailing newline and no key. There is no"
|
|
echo "properties syntax to parse -- the filename is the key."
|
|
echo
|
|
echo "== importing it =="
|
|
echo "\$ java -jar $JAR \\"
|
|
echo " --spring.config.import=configtree:$TREE/,configtree:$SECRET/"
|
|
echo
|
|
start_app "--spring.config.import=configtree:$TREE/,configtree:$SECRET/" > /dev/null
|
|
report demo.greeting
|
|
echo
|
|
echo " demo.pool-size = $(curl -s "http://127.0.0.1:${APP_PORT}/precedence?name=demo.pool-size" | python3 -c 'import json,sys; print(json.load(sys.stdin)["effectiveValue"])')"
|
|
echo " demo.nested.value = $(curl -s "http://127.0.0.1:${APP_PORT}/precedence?name=demo.nested.value" | python3 -c 'import json,sys; print(json.load(sys.stdin)["effectiveValue"])')"
|
|
echo " demo.api-key = $(curl -s "http://127.0.0.1:${APP_PORT}/precedence?name=demo.api-key" | python3 -c 'import json,sys; print(json.load(sys.stdin)["effectiveValue"])')"
|
|
echo
|
|
echo "A directory under the mount becomes a nested property: demo/nested/value is"
|
|
echo "demo.nested.value. That is how a ConfigMap with slashes in its keys arrives."
|
|
echo
|
|
echo "== the part that surprises people =="
|
|
echo "An imported config tree outranks application.yaml, but it is still config data,"
|
|
echo "so it still loses to an environment variable:"
|
|
echo
|
|
APP_ENV="DEMO_GREETING=from-environment-variable" \
|
|
start_app "--spring.config.import=configtree:$TREE/" > /dev/null
|
|
report demo.greeting
|
|
echo
|
|
echo "There is also no such thing as a profile-specific config tree. There is no"
|
|
echo "<mount>-prod directory convention; a per-environment ConfigMap is a different mount"
|
|
echo "chosen by the deployment, not by spring.profiles.active."
|
|
stop_app
|
|
} > docs/output/03-config-tree.txt 2>&1
|
|
cat docs/output/03-config-tree.txt
|