How to access a Spring Boot Application's name programmatically? - spring

I've defined an application name using the bootstrap.yml file in my spring boot application.
spring:
application:
name: abc
How can i get this application name during runtime/programmatically ?

You should be able to use the #Value annotation to access any property you set in a properties/YAML file:
#Value("${spring.application.name}")
private String appName;

#Autowired
private ApplicationContext applicationContext;
...
this.applicationContext.getId();
Please, find this:
# IDENTITY (ContextIdApplicationContextInitializer)
spring.application.name=
spring.application.index=
In Spring Boot Reference Manual.
And follow with source code for that ContextIdApplicationContextInitializer class:
#Override
public void initialize(ConfigurableApplicationContext applicationContext) {
applicationContext.setId(getApplicationId(applicationContext.getEnvironment()));
}
Where the default behavior is with this:
/**
* Placeholder pattern to resolve for application name
*/
private static final String NAME_PATTERN = "${vcap.application.name:${spring.application.name:${spring.config.name:application}}}";

Since the #Value annotation is discouraged in Spring Boot when referencing configuration properties, and because applicationContext.getId(); doesn't always return the value of spring.application.name another way is to get the value from the Environment directly
private final Environment environment;
...
public MyBean(final Environment environment) {
this.environment = environment;
}
...
private getApplicationName() {
return this.environment.get("spring.application.name");
}
Another possible way would be to create your own ConfigurationProperties class to get access to the value.
I'm not saying these are the best ways, and I hope/wish that there is a better way, but it is a way.

Note! If your using a SpringBootTest, you need to suplly the properties/yml.
Otherwise, the environment/appcontext does not load the config files.
The, your app name is not set.
Like so:
#PropertySource("classpath:application.properties")
#RunWith(SpringRunner.class)
#SpringBootTest
....

This post is aged but I hate unanswered questions.
So use the following snippet:
#Value("${spring.application.name [: defaultValue]}")
private String appName;
What is between [] is optional.

So I found a really ugly way to do this, but it works so I'm not searching further. Maybe this will help someone.
The basic premise is that spring Environment stores the value inside a propertySource.. It appears that bootstrap config is stored in the ResourcePropertySource and so you can get it from that. For me it is currently throwing an exception, but then I can get the value out of the exception, so I haven't looked any further:
try {
this.environment.getProperty("name", ResourcePropertySource.class);
} catch (ConversionFailedException e) {
String res = (String)e.getValue();
}
And then you can just do this for every property you are interested in.
Like I said ugly, but it works.

Related

Active profile in SpringBootTest based on system variable

As the host of Redis is different in local and CI, my #Tests can pass locally, they can't pass in CI.
Firstly, I tried to mock the RedisTemplate like this:
RedisTemplate redisTemplate = mock(RedisTemplate.class);
ValueOperations valueOperations = mock(ValueOperations.class);
when(redisTemplate.opsForValue()).thenReturn(valueOperations);
when(valueOperations.increment(anyString(), anyLong())).thenReturn(1L);
when(valueOperations.get("a#a.com")).thenReturn("1");
It did mocked RedisTemplate, but can't mock redisTemplate.opsForValue() and valueOperations.increment(...) ( I can't find reason )
Then, I wrote two profiles named application-ci-test.yml and applicaiton-test.yml, tried to active one of them based on system environment variable
I learnd from here that I can set active profile in this way:
#Configuration
public class MyWebApplicationInitializer
implements WebApplicationInitializer {
#Override
public void onStartup(ServletContext servletContext) throws ServletException {
servletContext.setInitParameter(
"spring.profiles.active", "dev");
}
}
and this way:
#Autowired
private ConfigurableEnvironment env;
...
env.setActiveProfiles("someProfile");
But I don't know how to use them. The system variable can get by System.getenv(..). So now I want to know how to active profile based on the variable I get.
I found a way to active corresponding profile based on system variable or property:
import org.springframework.test.context.ActiveProfilesResolver;
public class SpringActiveProfileResolver implements ActiveProfilesResolver {
#Override
public String[] resolve(Class<?> testClass) {
final String isCITest = System.getEnv("isCITest");
return new String[] { isCITest == null ? "test" : "ci-test" };
}
}
then use the parameter resolver in #ActiveProiles:
#ActiveProfiles(resolver = SpringActiveProfileResolver.class)
How to set environment variable is anther issue, and answers above have already answered it
Assuming your #Test methods are in a class with the #SpringBootTest annotation, you can use #ActiveProfiles to set the profile.
#SpringBootTest
#ActiveProfiles("someProfile")
Use run parameters inside your CI job/script.
Depending how You start Your tests, You can for example do it with VM arguments
mvn test -Dspring.profiles.active=ci-test
or
java -jar -Dspring.profiles.active=ci-test
or whatever.
On the other hand you can use program arguments:
java -jar --spring.profiles.active=ci-test
One way or the other, providing active profile at start will activate property file of your choice.
If you want some specific piece of code (configuration class for example) to be run with specific profile only, annotate that piece of code with #Profile("ci-test")
Example:
#Configuration
#Profile("ci-test")
public class SomeConfiguration {
//any configuration beans etc.
}
Following class will only be loaded when Your active profile will be "ci-test". So if You run Your app on Your CI server with one of the commands above, both property file named "ci-test" and this configuration class will get loaded.
It's also worth adding that in order for some code to run in ALL profiles EXCEPT specified, you can negate the name inside profile annotation like: #Profile("!ci-test").
Code annotated like that will run with all profiles (including default) except "ci-test".

Can you or can't you use a property from a config file when using Spring #Condition?

I have read pretty much everything I can find on StackOverflow and other sites and I don't see a definitive answer anywhere.
I have a class that implements #Condition that I use in a #Configuration file to conditionally load some beans. I am doing something like this:
public class MyCondition implements Condition {
#Override
public boolean matches(ConditionContext context, AnnotatedTypeMetadata metdata) {
String property = context.getEnvironment().getProperty("some.prop.from.file");
boolean enable = Boolean.parseBoolean(property);
return enable;
}
}
When debugging I see that getting the property from the environment always returns null, even though the property is injected in other beans using #Value.
So my question can you or can't you attempt to get a property value from a file within a #Condition class? Can you only get System properties? I would think that this is a common use case that I would think Spring could handle.
Had to add the property to application.properties and not the other property files that are loaded during startup.

how to load property file in to spring boot project with annotations?

I have written queries in property file. I want to read the property file in to one class with annotations in spring boot. How can i read it? And is there any better approach for writing queries in spring boot project?
If you add your properties in application.properties file, you can read them inside the spring boot classes like:
#Service
public class TwitterService {
private final String consumerKey;
private final String consumerKeySecret;
#Autowired
public TwitterService(#Value("${spring.social.twitter.appId}") String consumerKey, #Value("${spring.social.twitter.appSecret}") String consumerKeySecret) {
this.consumerKey = consumerKey;
this.consumerKeySecret = consumerKeySecret;
} ...
You can annotate fields in your components by #Value("${property.name}")
Else, you can use Properties Object in java.util package.
For example, i have a mode property, which values are dev or prod, i can use it in my beans as follow :
#Value("${mode:dev}")
private String mode;
The other approach is by using :
Properties pro = new Properties();
pro.load(this.getClass().getClassLoader().getResourceAsStream());
You can use #PropertySource to read the properties from a file and then pass them to a bean. If you have a file called "queries.properties" that has a property like:
query1: select 1 from foo
Then your config might look like:
#PropertySource("classpath:queries.properties")
#Configuration
public class MyConfig {
#Bean
public DbBean dbBean(#Value("${queries.query1}") String query) {
return new DbBean(query);
}
}

Spring boot access application.properties in components

I want to add a property in application.properties of my spring boot application and be able to to access it and use it in one of my other classes, but I am getting null.
Here is my application.properties
server.port=8052
subscribe.period=5
My class that will access it
#Component
public class SubscriptionService {
#Value("${subscribe.period}")
private String period
#Autowired
public SubscriptionService(String period) {
String time = period;
...
}
}
But it seems period is not being populated, in fact null. It shows as nill when I run as maven build in eclipse at least, im thinking it might be trying to access it before the properties file is even load, if so how might i approach this?
Deinum in the comments above is correct. I have no idea why as it differs from every other online example I have read so I would invite him to give an explanation.
I had to put the #Value in the argument of the constructor
#Component
public class SubscriptionService {
private String period
#Autowired
public SubscriptionService(#Value("${subscribe.period}") String period) {
String time = period;
...
}
}
Then it works

Spring Boot - Detect and terminate if property not set?

Is there any way for a Spring Boot web application to abort at startup if a required property is not set anywhere (neither in the application.properties file nor the other property sources)? Right now, if the property is included in another property, it seem that Spring Boot simply avoids substitution.
For example, in my application.properties file, I have the line:
quartz.datasource.url=jdbc:hsqldb:${my.home}/database/my-jobstore
Right now, if "my.home" is not set elsewhere, Spring Boot is setting the url literally to "jdbc:hsqldb:${my.home}/database/my-jobstore" (no substitution).
I would like to have the application fail to start if the property my.home were not set anywhere else.
To throw a friendly exceptions just put a default null value in property, check and throw a exception in afterProperty method.
#Component
public static class ConfigurationGuard implements InitializingBean {
#Value("${my.home:#{null}}")
private String myHomeValue;
public void afterPropertiesSet() {
if (this.myHomeValue == null or this.myHomeValue.equals("${my.home}") {
throw new IllegalArgumentException("${my.home} must be configured");
}
}
}
Create a bean with a simple #Value(${my.home}) annotated field. - Then Spring will try to inject that value and will fail and therefore stop when the value is not there.
Just #Value(${my.home}) private String myHomeValue; is enough for normal (not Boot) Spring applications for sure! But I do not know whether Boot has some other configuration to handle missing values: If there is an other failure management than you could check that value in an PostCreation method.
#Component
public static class ConfigurationGuard implements InitializingBean {
#Value(${my.home})
private String myHomeValue;
/**
* ONLY needed if there is some crude default handling for missing values!!!!
*
* So try it first without this method (and without implements InitializingBean)
*/
public void afterPropertiesSet() {
if (this.myHomeValue == null or this.myHomeValue.equals("${my.home}") {
throw new IllegalArgumentException("${my.home} must be configured");
}
}
}
The default behaviour in current versions of Spring Boot (1.5.x, 2.0.x, 2.1.x) is to throw an exception if a placeholder can not be resolved.
There will a be an exception like this one :
Caused by: java.lang.IllegalArgumentException: Could not resolve placeholder 'app.foo.undefined' in value "${app.foo.undefined}"
It works because a bean of type PropertySourcesPlaceholderConfigurer (from spring-context) is automatically registered in Spring Boot, in this class : PropertyPlaceholderAutoConfiguration. And by default, the property ignoreUnresolvablePlaceholders in PropertySourcesPlaceholderConfigurer is set to false, which means an exception must be thrown if a placeholder is unresolved (be it nested or not).
Although they work, I think the approach in the foremost answer is somewhat brittle, as it only works for the predefined name(s), and will silently stop checking the when someone changes quartz.datasource.url in the configs to use a different expansion.
Ideally, I want this value of ignoreUnresolvablePlaceholders to be false to get wholesale expansion checking when parsing my configs such as application.properties or its YAML variants, but it's hard-coded to true for these cases. This unfortunately leaves strings such as ${FOO} in its unexpanded form if FOO cannot be found, making troubleshooting extremely painful. This is especially the case for fields that don't readily appear in the logs such as passwords.
While I couldn't find a way of changing ignoreUnresolvablePlaceholders short of modifying Spring Boot's classes, I did find an alternative of using a custom PropertySource implementation and defining a new syntax such as "${!FOO}" to indicate FOO must exist as an environment variable or die. (The OP didn't mention whether my.home is an environment variable but the code below is for environment variables.)
First, an EnvironmentPostProcessor implementation is required for registering the custom PropertySource. This StrictSystemEnvironmentProcessor.java does this as well as holds the implementation of the custom PropertySource:
package some.package;
#Order(Ordered.LOWEST_PRECEDENCE)
class StrictSystemEnvironmentProcessor implements EnvironmentPostProcessor {
private static final String PROPERTY_SOURCE_NAME = "STRICT_" + StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME;
#Override
public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) {
if (environment.getPropertySources().contains(PROPERTY_SOURCE_NAME)) {
return;
}
SystemEnvironmentPropertySource delegate = (SystemEnvironmentPropertySource)environment.getPropertySources()
.get(StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME);
environment.getPropertySources().addLast(new StrictSystemEnvironmentPropertySource(delegate));
}
private static class StrictSystemEnvironmentPropertySource extends SystemEnvironmentPropertySource {
public StrictSystemEnvironmentPropertySource(SystemEnvironmentPropertySource delegate) {
super(PROPERTY_SOURCE_NAME, delegate.getSource());
}
#Override
public Object getProperty(String name) {
if (name.startsWith("!")) {
String variableName = name.substring(1);
Object property = super.getProperty(variableName);
if (property != null) {
return property;
}
throw new IllegalStateException("Environment variable '" + variableName + "' is not set");
}
return null;
}
}
}
Instead of returning null, an exception is thrown for names that start with !.
This META-INF/spring.factories is also required so that Spring initializes our EnvironmentPostProcessor:
org.springframework.boot.env.EnvironmentPostProcessor=some.package.StrictSystemEnvironmentProcessor
Then henceforth, I can write all environment variables substitutions in my configs as ${!FOO} to get strict existance checking.
You can also create a #ConfigurationProperties bean, and decorate it with #Validated and #NotNull. This will throw an exception during startup when the value is not present (or null), e.g.
#Validated
#ConfigurationProperties("my")
public class MyProperties {
#NotNull
private String home;
// getter/setter, or constructor. See #ConstructorBinding.
}
For reference: Spring Boot 2.6 - #ConfigurationProperties Validation.
Note that you may need to add spring-boot-starter-validation, or another validator, depending on your project.
Then, you can just supply it as a dependency when needed, e.g.
#Component
public class AnotherBean {
private final MyProperties myProps;
public AnotherBean(MyProperties myProps) {
this.myProps = myProps;
}
// some code that uses myProps.getHome()
}

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