Debug mode should not be triggered only by the presence of a "debug" env property

[jiahut]

As soon as system environment exist the debug variable, the spring boot will set springBootLogging to debug

It is so freedom

in my case, oneday, someone executed some program like shell, it had been set environment variable debug = 1 or trace careless. when restart, it set the springBootLogging to debug.

We can't restrict others from doing so.

I think set springBootLogging to debug so freedom , it should be added some prefix

look at LoggingApplicationListener.java

private void initializeEarlyLoggingLevel(ConfigurableEnvironment environment) {
	if (this.parseArgs && this.springBootLogging == null) {
		if (isSet(environment, "debug")) {
			this.springBootLogging = LogLevel.DEBUG;
		}
		if (isSet(environment, "trace")) {
			this.springBootLogging = LogLevel.TRACE;
		}
	}
}

[philwebb]

This is one part of a broader problem that's discussed in #3450 and I don't think we can change the existing behavior without breaking existing apps. If would be nice if we could offer a quick way to opt-out of picking up those flags from the system environment.

[philwebb]

I think we should consider this a duplicate of #3450.

@jiahut If you want a work-around until #3450 is fixed you can do something like the following:

SpringApplication springApplication = new SpringApplication(MyApp.class);
for(ApplicationListener<?> listener: springApplication.getListeners()) {
  if (listener instanceof LoggingApplicationListener) {
    ((LoggingApplicationListener) listener).setParseArgs(false);
  }
}

[jiahut]

@philwebb thinks. +1 for #3450