fix(logging): emit the log level in JSON logs - #15
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The JSON encoder was configured with a <level/> provider, but logstash-logback-encoder has no such provider — LoggingEventJsonProviders exposes addLogLevel and addLogLevelValue, not addLevel. Logback silently dropped the element and only hinted at it in its startup status output: |-WARN in ch.qos.logback.core.model.processor.ImplicitModelHandler - Ignoring unknown property [level] in [net.logstash.logback.composite.loggingevent.LoggingEventJsonProviders] So every log line went out without a level, while app/environment/instance survived because they come from the separate, valid <pattern> provider. That made the breakage easy to miss: nothing failed, the logs were still valid JSON, and only one field was quietly absent. Verified with ./gradlew bootRun on the dev profile. Before: 0 of 38 lines had a level field and the warning above was present. After: all 46 lines carry level, spanning DEBUG/INFO/WARN, and the warning is gone.
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Проблема
В JSON-логах приложения нет уровня логирования. Замечено наставником при разборе проекта «Доска объявлений (Observability)» — там шаг про Promtail/Loki опирается на то, что логи уже в JSON и пригодны для фильтрации по уровню.
Симптом выглядел странно: поля
app,environmentиinstanceиз того же самого appender'а пишутся, аlevel— нет.Причина
В
logback-spring.xmlпровайдер назывался<level/>. Вlogstash-logback-encoderтакого провайдера нет:LoggingEventJsonProvidersпредоставляетaddLogLevelиaddLogLevelValue, но неaddLevel. Logback молча выбрасывал неизвестный элемент, оставив лишь строку в своём startup-статусе:app/environment/instanceвыживали потому, что приходят из отдельного, валидного провайдера<pattern>.Поэтому баг и было легко не заметить: сборка не падала, логи оставались валидным JSON, просто одного поля тихо не было.
Фикс
<level/>→<logLevel/>, одна строка.Проверка
./gradlew bootRun, профильdev(h2, без внешних зависимостей):levelПосле фикса в логах присутствуют уровни
DEBUG,INFOиWARN— то есть поле живое, а не константа. Пример строки:{"@timestamp":"2026-08-04T17:50:49.842989867Z","app":"bulletins","environment":"dev", "instance":"linux-mint","logger_name":"io.hexlet.project_devops_deploy.DemoApplication", "thread_name":"restartedMain","level":"INFO", "message":"Started DemoApplication in 11.896 seconds (process running for 12.731)"}Тикет: FEEDBACK-353.