Is there a way in spring-boot YAML file to do the same as in HOCON files where you can have a default and be able to override it with an environment variable like this:
basedir = "/whatever/whatever"
basedir = ${?FORCED_BASEDIR}
In this case in HOCON if you don't define a environment variable named FORCED_BASEDIR then basedir will be "/whatever/whatever" but if you do then the value of basedir will be whatever is defined in the environment variable.
Thanks
So based on webdizz answer below I looked up a little bit and I found a pretty good description in book "Spring Boot in Action". Here is the hierarchy:
There are, in fact, several ways to set properties for a Spring Boot application. Spring
Boot will draw properties from several property sources, including the following:
Command-line arguments
JNDI attributes from java:comp/env
JVM system properties
Operating system environment variables
Randomly generated values for properties prefixed with random.* (referenced
when setting other properties, such as `${random.long})
An application.properties or application.yml file outside of the application
Licensed to Thomas Snead 58 CHAPTER 3 Customizing configuration
An application.properties or application.yml file packaged inside of the
application
Property sources specified by #PropertySource
Default properties
Spring Boot provides means to define variables at many levels and your case is supported, you just need to define variable in following way:
in application.yml:
basedir: "/whatever/whatever"
and in environment:
export BASEDIR = "/another/whatever"
Then in runtime application will use value from environment.
For more details check this out enter link description here.
Related
I am setting the logging.file.name in application.properties file which I want to pass as command line argument. Is it possible?
The reason is I am trying to run multiple jar files from a single application and I want to display logs of each application run at a single location.
Spring Boot provides several options to externalize configuration.
Spring Boot uses a very particular PropertySource order that is
designed to allow sensible overriding of values. Properties are
considered in the following order (with values from lower items
overriding earlier ones):
Default properties (specified by setting SpringApplication.setDefaultProperties).
#PropertySource annotations on your #Configuration classes. Please note that such property sources are not added to the
Environment until the application context is being refreshed. This is
too late to configure certain properties such as logging.* and
spring.main.* which are read before refresh begins.
Config data (such as application.properties files).
A RandomValuePropertySource that has properties only in random.*.
OS environment variables.
Java System properties (System.getProperties()).
JNDI attributes from java:comp/env.
ServletContext init parameters.
ServletConfig init parameters.
Properties from SPRING_APPLICATION_JSON (inline JSON embedded in an environment variable or system property).
Command line arguments.
properties attribute on your tests. Available on #SpringBootTest and the test annotations for testing a particular
slice of your application.
#TestPropertySource annotations on your tests.
Devtools global settings properties in the $HOME/.config/spring-boot directory when devtools is active.
So you should be possible to override the values defined in your application.properties by setting environment variables, Java system properties, or command line arguments:
Environmant variables: export LOGGING_FILE_NAME=yourfile.txt
Java system property: -Dlogging.file.name=yourfile.txt
Command line argument: --logging.file.name=yourfile.txt
If I run my app as java jar -Dsomething=anything thejar.jar then I have set a system property.
Can I do that via Spring Boot Configuration files or is my only option to defined a #Configuration class that reads a property and then sets the system property from that?
Spring configuration is highly flexible and provides a hierarchy for resolving configuration properties. You can set properties using the spring config server, environment variables (my preferred approach), system properties, application.yaml/propteries, etc. Check out the docs on externalized configuration
Say you wanted to set a property: app.some.property=foo. You can access this property from any bean using the value annotation:
#Value("${app.some.property}")
private String someProperty;
And then you can set it at runtime using one of the approaches defined above:
1. System Property
java -jar -Dapp.some.property=foo thejar.jar
2. Environment Variable
export APP_SOME_PROPERTY="foo"
java -jar thejar.jar
I have specified an external properties file to a Spring Boot app by setting spring.config.additional-location in the SpringApplicationBuilder.
new SpringApplicationBuilder(MyApplication)
.properties(['spring.config.additional-location': myExternalProperties])
.run(myArgs)
This works insofar as it allows me to override properties in the application.properties file using myExternalProperties.
However, myExternalProperties are in turn overridden by any profile-specific properties, e.g. application-myProfile.properties.
I understand this to be consistent with Spring's prioritization of Externalized Configuration, but I want myExternalProperties to override even profile-specific properties.
How can I achieve that order of priority?
I do not control the file name or location of myExternalProperties. This variable is a System property that is preset in the environment.
I have been looking at Profile-specific Properties and in particular this quote.
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.
I assume this note applies equally to spring.config.additional-location, but without control over the property file name or location I don't think that helps me.
I'm afraid it cannot be achieved in a non-hacky way.
The docs state:
Profile-specific files always overriding the non-specific ones.
Also:
If several profiles are specified, a last-wins strategy applies. For example, profiles specified by the spring.profiles.active property are added after those configured through the SpringApplication API and therefore take precedence.
Could you consider using profile based configuration for myExternalProperties?
You can even use env vars as placeholders.
Hope this helps: Env vars in Spring boot properties
New to spring boot.
While exploring spring boot env variables, came to know that,
env variables can be accessed by ${KeyName} from code.
Got a question like,
Case 1:
In #Configuration files, we are accessing keys in application.properties using #Value(value = "${KeyName}").
So, we are using almost same syntax for accessing env variables and accessing keys in application.properties.
Case 2:
When trying to access the keys in application.properties using system.getEnv("keyname"), I got only null.
Case 3:
Recently worked on configmap in kubernetes with spring boot.
Config file looks like,
spec:
containers:
- name: demo-configconsumercontainer
image: springbootappimage:latest
ports:
- containerPort: 8080
envFrom:
- configMapRef:
name: example-configmap
All the values from configMap is exported as environmental variables and
I am accessing those values by #Value(value = "${KeyName}") and by system.getEnv(KeyName).
My question is, how case 3 is working when case 2 is not.
Is Spring boot made such a way that, it is allowing to access by ${KeyName} and not by system.getEnv(KeyName)? (ie. Case 2)
Could some one clarify my questions here.
Using #Value annotation, you can access a property from many property sources such as in application.properties or an environment variable and few more property sources.
The important point here is ordering of these property sources.
Below is the order of looking up the property in various sources.
Devtools global settings properties on your home directory (~/.spring-boot-devtools.properties when devtools is active).
#TestPropertySource annotations on your tests.
#SpringBootTest#properties annotation attribute on your tests.
Command line arguments.
Properties from SPRING_APPLICATION_JSON (inline JSON embedded in an environment variable or system property)
ServletConfig init parameters.
ServletContext init parameters.
JNDI attributes from java:comp/env.
Java System properties (System.getProperties()).
OS environment variables.
A RandomValuePropertySource that only has properties in random.*.
Profile-specific application properties outside of your packaged jar (application-{profile}.properties and YAML variants)
Profile-specific application properties packaged inside your jar (application-{profile}.properties and YAML variants)
Application properties outside of your packaged jar (application.properties and YAML variants).
Application properties packaged inside your jar (application.properties and YAML variants).
#PropertySource annotations on your #Configuration classes.
Default properties (specified using SpringApplication.setDefaultProperties).
In your case, the property is either declared in environment variable or in application.yaml and hence accessible using #Value annotation.
See the Spring docs:
https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-external-config.html
Spring includes environment variables as a potential property source, but does not export its properties defined in other ways as environment variables. So it isn't a two way street, which is why case #2 does not work.
Case #3 is a separate reality, just the fact that when K8s runs a container defined in this way with env vars, it makes those vars available in the container environment. Any software system or programming language able to read environment variables will be able to refer to those variables, including Java code. This has nothing to do specifically with Java or Spring...it's just another way to inject environment variables into the runtime environment.
UPDATE: I didn't see #ShaileshPratapwar's answer until I posted my own. Seems our answers are roughly the same, although I think it's good that you know where the list of property sources, and their order of priority, comes from. It's very clearly defined by the Spring docs.
Can expressions be used as a right-hand-side value in a Spring application.properties file?
For example, something like this:
logging.level.com.acme=#{'${MY_RUN_ENV}'=='PROD'?'WARN':'DEBUG'}
That, specifically, does not work. But, I'm wondering if I can do something similar to what's intended there
No you can not use SpEL within properties files.
Finally, while you can write a SpEL expression in #Value, such
expressions are not processed from Application property files.
You can however use placeholders within properties files, eg:
app.name=MyApp
app.description=${app.name} is a Spring Boot application
For your use case, you should look at the profile-specific configuration mechanism.
Which allows you to load different config based on an environment profile.
No this is not possible, From spring boot reference:
Feature #ConfigurationProperties
SpEL evaluation No
Instead you can have an application-default.properties in production and in it define loglevel=WARN.
And in your application.properties:
loglevel=DEBUG
logging.level.com.acme=${loglevel}
The profile-specific properties file(-default by default) should override the properties from application.properties, more info here.
Use profile based properties file.
In application-dev.properties :
logging.level.com.acme=WARN
and in application-prod.properties :
logging.level.com.acme=DEBUG
FYI when spring boot doesn't find a propertie in a profile based file it use the value in the default one . So you can set properties in application.properties and override them in a profile based file when their value changed.