Spring boot WAR in tomcat - externalize the application.properties

Question

I have a Spring boot app that is packaged as a WAR and deployed into tomcat. It is deployed this way because of some legacy issues.

I am having issues externalizing the application.properties
DevOps team require the file to be under /app/shared/conf/
I found many questions about this topic but none of the solutions seems to work...
This is what I tried so far:

added to tomcat's Context.xml:

<Parameter name="spring.config.location" value="/app/shared/conf/application.properties" />

added to startup.sh:

export spring_config_location=/app/shared/conf/

added to startup.sh:

export SPRING_CONFIG_LOCATION=/app/shared/conf/application.properties

added to startup.sh , and setting this on SecurityConfig extends WebSecurityConfigurerAdapter

CLASSPATH=/app/shared/conf/
@PropertySource("classpath:application.properties")

Added to application main class:

 System.setProperty("spring.config.location", "/app/shared/conf/application.properties");

Added to SecurityConfig extends WebSecurityConfigurerAdapter

@PropertySource("file:/app/shared/conf/application.properties")

This is the error I keep getting:

 .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::             (v2.2.0.M1)

11-Jun-2019 02:54:22.034 SEVERE [localhost-startStop-1] org.apache.catalina.core.ContainerBase.addChildInternal ContainerBase.addChild: start: 
 org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/prntPrtl]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:754)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:730)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:734)
    at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:986)
    at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1857)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThrexeroxoolExecutor.runWorker(ThrexeroxoolExecutor.java:1142)
    at java.util.concurrent.ThrexeroxoolExecutor$Worker.run(ThrexeroxoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
Caused by: org.springframework.beans.factory.BeanDefinitionStoreException: Failed to parse configuration class [com.xerox.printHub.app.PrinterPortal]; nested exception is java.io.FileNotFoundException: class path resource [application.properties] cannot be opened because it does not exist
    at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:181)
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:315)
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:232)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:275)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:95)
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:705)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:531)
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:142)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:785)
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:407)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:322)
    at org.springframework.boot.web.servlet.support.SpringBootServletInitializer.run(SpringBootServletInitializer.java:157)
    at org.springframework.boot.web.servlet.support.SpringBootServletInitializer.createRootApplicationContext(SpringBootServletInitializer.java:137)
    at org.springframework.boot.web.servlet.support.SpringBootServletInitializer.onStartup(SpringBootServletInitializer.java:91)
    at org.springframework.web.SpringServletContainerInitializer.onStartup(SpringServletContainerInitializer.java:171)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5204)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    ... 10 more
Caused by: java.io.FileNotFoundException: class path resource [application.properties] cannot be opened because it does not exist
    at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:180)
    at org.springframework.core.io.support.EncodedResource.getInputStream(EncodedResource.java:159)
    at org.springframework.core.io.support.PropertiesLoaderUtils.fillProperties(PropertiesLoaderUtils.java:99)
    at org.springframework.core.io.support.PropertiesLoaderUtils.fillProperties(PropertiesLoaderUtils.java:73)
    at org.springframework.core.io.support.PropertiesLoaderUtils.loxeroxroperties(PropertiesLoaderUtils.java:59)
    at org.springframework.core.io.support.ResourcePropertySource.<init>(ResourcePropertySource.java:67)
    at org.springframework.core.io.support.DefaultPropertySourceFactory.createPropertySource(DefaultPropertySourceFactory.java:37)
    at org.springframework.context.annotation.ConfigurationClassParser.processPropertySource(ConfigurationClassParser.java:452)
    at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:271)
    at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:242)
    at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:191)
    at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:295)
    at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:242)
    at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:199)
    at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:167)
    ... 26 more

Answer 1

The documentation has several important notes:

spring.config.name and spring.config.location are used very early to determine which files have to be loaded, so they must be defined as an environment property (typically an OS environment variable, a system property, or a command-line argument).

and

If spring.config.location contains directories (as opposed to files), they should end in / (and, at runtime, be appended with the names generated from spring.config.name before being loaded, including profile-specific file names). Files specified in spring.config.location are used as-is, with no support for profile-specific variants, and are overridden by any profile-specific properties.

and

When custom config locations are configured by using spring.config.location, they replace the default locations.

and, finally

If you have specified any files in spring.config.location, profile-specific variants of those files are not considered. Use directories in spring.config.location if you want to also use profile-specific properties.

So

• It's probably better to use directories rather than files in spring.config.location
• Add your directory to the default locations unless you don't need them.
• Make sure the directories end with a slash.
• You also need to use a protocol file: to reference to a file outside the classpath.

In summary, this should work: Export an environment variable in Tomcat's setenv.sh script

export SPRING_CONFIG_LOCATION=classpath:/,classpath:/config/,file:./,file:./config/,file:/app/shared/conf/

or use a system property (-Dspring.config.location) or command line flag (--spring.config.location) instead.