How to get Environment properties from application.properties into logback.groovy in Spring Boot project? - spring

Question

Trying to inject properties defined in application.properties/application.yml into logback.groovy script in Spring Boot project.
I cannot Inject Environment or ApplicationContext into groovy scripts.
Are there any workarounds?
I am not looking for solutions like System.getProperty('spring.profiles.active')
src/main/resources/logback.groovy
import org.springframework.core.env.Environment
#Inject private Environment env; //this is not working. how to get env here?
println "spring.profiles.active : ${env.getProperty('spring.profiles.active')}"
appender("STDOUT", ConsoleAppender) {
encoder(PatternLayoutEncoder) {
pattern = "%green(%d{HH:mm:ss.SSS}) [%thread] %highlight(%-5level) %cyan(%logger{36}) - %msg%n"
}
}
if(System.getProperty("spring.profiles.active")?.equalsIgnoreCase("prod")) {
root INFO, ["STDOUT", "FILE"]
} else {
root INFO, ["STDOUT"]
}
src/main/resources/application.yml
---
spring:
profiles:
active: development

Answer 1

logback.groovy needs to be evaluated very early because otherwise the code for loading the spring configuration, instantiating beans, etc. could not log anything. That's why #Inject can't work.
I see 2 options:
You could easily load application.properties in logback.groovy, but it's far from trivial to take all the configuration override mechanisms that spring provides into account
Create a spring bean that changes the logback configuration programmaticaly
when initialized
A different approach is to externalize the logback configuration on production with -Dlogback.configurationFile=/path/to/config.groovy. Putting the config file in a well known location (like /etc/my-app) makes it easy to change log levels in production without re-deploying (or even re-starting).

Answer 2

Sorry to resurrect this thread but while since this is thread is what I found while looking for a solution, I wanted to share a workaround.
I have used a Custom converter and conversion rule to pull out properties in classpath resource (i.e. application.properties):
In logback.groovy:
conversionRule('springApplicationName', CustomSpringApplicationNameConverter)
def patternExpression = '%green([%d{YYYY-MM-dd HH:mm:ss.SSS}]) [%t] %highlight(%-5level) %magenta([%springApplicationName]) - %cyan(%logger{36}) -- %msg%n'
and then 'patternExpression' used in desired appender
and my custom converter class (in groovy):
class CustomSpringApplicationNameConverter extends ClassicConverter {
#Override
String convert(ILoggingEvent event) {
ClassPathResource classPathResource = new ClassPathResource('application.properties')
Properties applicationProperties = new Properties()
applicationProperties.load(classPathResource.inputStream)
String springApplicationName = applicationProperties.getProperty('spring.application.name')
if (!springApplicationName) {
System.err.println('Could not find entry for \'spring.application.name\' in \'application.properties\'')
}
springApplicationName
}
}