Simplifying deployment configs for SpringMVC project - spring

We've multi module SpringMVC project, each having separate applicationContext.xml, currently we have to edit the applicationContext.xml files for every module before we deploy. It's painful and error prone. Is there a way to have only one property file that all other will contexts look at. Then we only have to edit one property file before we build and deploy. Thanks in advance.

It sounds like you should be using Spring's Profile support, which allows you to specify separate properties files per environment. You can pass the application an environment property spring.profiles.active and set it to say, "dev", "test", or "prod".
If you're using Spring Boot it can then automatically pick up distinct configuration per environment, application.dev.properties or application.prod.properties which will overwrite the standard application.properties with environment specific configuration.
If not using Spring Boot you would just have configure your Properties Sources per profile.
This is most definitely the preferred approach to changing configuration files at build or deploy time.
Reference: http://docs.spring.io/spring/docs/current/spring-framework-reference/htmlsingle/#beans-environment

Related

Quarkus: How to define and read properties file (or application.properties) outside application or at runtime?

In Quarkus, We have properties file inside project itself called application.properties.
Is there any Quarkus way to define external properties file in my use case like i am developing a mail sender and i want to add recipients in future.
Is it possible to give application.properties outside at local and inject it at runtime?
You can add a configuration file in your application working directory under config/application.properties : https://quarkus.io/guides/config#overriding-properties-at-runtime
There is ongoing discussion to have more runtime configuration capabilities here: https://github.com/quarkusio/quarkus/issues/1218
You can achieve this by keeping .properties (or .yaml) in Spring Cloud Config Server.
It's really easy to set it up. It's is well documented in following link (official documentation):
Quarkus - Reading properties from Spring Cloud Config Server
As loïc says, you can follow the convention and create a config/application.properties. You can also use the property quarkus.config.locations to specify additional config locations. It can be defined at runtime like below
java -Dquarkus.config.locations=app-config/config.properties -jar my-app.jar

How to make Spring Boot skipping some configurations

I have a Spring-Boot project which works with DB-connections and a lot of other stuff.
Now I added another "main-class" to the project. The thing is: by starting this class, all configuration settings (which come from application.yml) are loaded. But thats not what I want.
I want the project to start without trying to bind to any datasource...
But how?
Why do you add several main classes? Try using different profiles instead. And you can start your application with the -Dspring.profiles.active=? property.
Example:
Just add a application-test.properties and run your application with -Dspring-profiles.active=test and the properties in the test property file will be loaded. And potentially overwrite properties with the same key in application.properties.

No plain text passwords in Spring Boot’s application.properties

Having something like
security.user.password = plainTextPassword
inside Spring Boot’s application.properties is obviously an anti-pattern as it prevents the code from being pushed to a public SCM. In my non-Spring Boot projects I use
security.user.password = ${myPasswordFromMavenSettingsXML}
and put a corresponding <properties/> reference inside my pom.xml.
Using Maven’s resource filter plugin the passwords are replaced at build time so the application have access to actual plain text passwords after it has been build and deployed.
For some reason Maven’s resource filter plugin does not work in this case. Is there a way to not commit plain text passwords to an SCM and let Spring Boot to insert them at build time?
Spring boot has multiple mechanisms to provided externalized configuration. Some examples are command line arguments, environment variables and also application properties outside of your packaged JAR.
What I usually do:
Locally we configured several environment variables. Most (if not all) IDE's allow you to configure environment variables from within the run configuration.
For example if you don't want to expose the spring.datasource.password property you could set an environment variable called SPRING_DATASOURCE_PASSWORD.
When we deploy on another environment, we usually choose to add another application.properties or application.yml file within the same folder as the application JAR/WAR, since Spring boot picks that up as well.
Another solution is to use Spring cloud since it has a config service which can be used as a microservice to provide configuration. The configuration can be versioned using SCM as well, but you can put it on a separate system that is not connected to your source code.

Spring boot application.properties maven multi-module projects

We are using spring boot in a multi-module project.
We have a Domain access module which has the common domain object classes, repositories, together with configuration for the datasource, JPA, Hibernate, etc. These are configured using a application.properties. We put all this configuration into the common module to save duplicating these common configurations in the higher level modules.
This all works fine when building the domain module, so the configurations are loaded correctly in the test units.
However the problems start when we try to use the domain module in the higher layer modules; they have their own application.properties which means Spring loads them and not the the Domain module application.properties, which this means the data source is not configured because only the higher module application.properties are loaded.
What we would like is both the domain module and higher level application properties to be loaded by Spring. But we can't see any easy way to do this.
I'm thinking this must be a common problem, and wonder if there any recommended solutions for this problem?
As we are using spring-boot the solution should ideally use annotations instead of applictionContext.xml.
Maybe you should only use application.properties in the top-level aggregator project?
You can always use #PropertySource in the child projects to configure them with a name that is specific to their use case.
Or you can use different names for each project and glue them together in the top-level project using spring.config.location (comma-separated).
I agree with #Dave Syer. The idea of splitting an application into multiple modules is that each of those is an independent unit, in this case a jar file. Theoretically you could split each of those jar files into their own source repositories, and then use them across multiple projects. Let's say you want to reuse these domain classes in both a web and batch application, if all the APPLICATION level configuration is stored within each of the individual modules, it severely reduces their reusability.
IMO only the aggregating module should contain all of the configuration necessary to run as an application, everything else is simply a dependency that can be remixed and reused as necessary.
Maybe another approach could be to define specific profiles for each module and use the application.properties file just to specify which profiles are active
using the spring.profiles.include property.
domain-module
- application.properties
- application-domain.properties
app-module
- application.properties
- application-app.properties
and into the application.properties file of app-module
spring.profiles.include=domain,app
Another thing you can do (besides only using application.properties at the top-level as Dave Syer mentions) is to name the properties file of the domain module something like domainConfig.properties.
That way you avoid the name clash with application.properties.
domainConfig.properties would contain all the data needed for the domain module to be able to tested on it's own. The integration with the rest of the code can easily be done either using multiple #PropertySource (one for domainConfig.properties and one for application.properties) or configuring a PropertySourcesPlaceholderConfigurer bean in your Java Config (check out this tutorial) that refers to all the needed property files
in spring-boot since 2.4 support spring.config.import
e.g
application.name=myapp
spring.config.import=developer.properties
# import from other module
spring.config.import=classpath:application-common.properties
or with spring.config.activate.on-profile
spring.config.activate.on-profile=prod
spring.config.import=prod.properties
ref: https://spring.io/blog/2020/08/14/config-file-processing-in-spring-boot-2-4

Having spring bean properties refreshed automatically from properties file

I'm using Spring 2.5.6. I have a bean whose properties are being assign from a property file via a PropertyPlaceholderConfigurer. I'm wondering whether its possible to have the property of the bean updated when the property file is modified. There would be for example some periodic process which checks the last modified date of the property file, and if it has changed, reload the bean.
I'm wondering if there is already something that satisfies my requirements. If not, what would be the best approach to solving this problem?
Thanks for your help.
Might also look into useing Spring's PropertyOverrideConfigurer. Could re-read the properties and re-apply it in some polling/schedular bean.
It does depend on how the actual configured beans use these properties. They might, for example, indirectly cache them somewhere themself.
If you want dynamic properties at runtime, perhaps another way to do it is JMX.
One way to do this is to embed a groovy console in your application. Here's some instructions. They were very simple to do, btw - took me very little time even though I'm not that familiar with groovy.
Once you do that you can simply go into the console and change values inside the live application on the fly.
You might try to use a custom scope for the bean that recreates beans on changes of the properties file. See my more extensive answer here.
Spring Cloud Config has facilities to change configuration properties at runtime via the Spring Cloud Bus and using a Cloud Config Server. The configuration or .properties or .yml files are "externalized" from the Spring app and instead retrieved from a Spring Cloud Config Server that the app connects to on startup. That Cloud Config Server retrieves the appropriate configuration .properties or .yml files from a GIT repo (there are other storage solutions, but GIT is the most common). You can then change configuration at runtime by changing the contents of the GIT repo's configuration files--The Cloud Config Server broadcasts the changes to any Client Spring applications via the Spring Cloud Bus, and those applications' configuration is updated without needing a restart of the app. You can find a working simple example here: https://github.com/ldojo/spring-cloud-config-examples

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