Spring Boot App does not recognize environment variables in application.yml file

Question

there. I'm new to Java Spring Boot and I'm trying to set environment variables in application.yml.

I've added dotenv maven dependency:

<!-- https://mvnrepository.com/artifact/io.github.cdimascio/java-dotenv -->
        <dependency>
            <groupId>io.github.cdimascio</groupId>
            <artifactId>java-dotenv</artifactId>
            <version>5.1.3</version>
        </dependency>

I've set variables in the .env file:

SPRING_DATABASE_URL = jdbc://db_url
SPRING_DATABASE_USERNAME = username
SPRING_DATABASE_PASSWORD = password

And in my application.yml:

spring:
    datasource:
        url: ${SPRING_DATABASE_URL}
        username: ${env.SPRING_DATABASE_USERNAME}
        password: ${env.SPRING_DATABASE_PASSWORD}

While running application I'm getting jdbc error:

java.lang.RuntimeException: Driver org.postgresql.Driver claims to not accept jdbcUrl, ${SPRING_DATABASE_URL}

I've tried some solutions like:

export SPRING_DATABASE_URL = jdbc://db_url

or in application.yml:

url: ${env.SPRING_DATABASE_URL}

or

url: ${env.SPRING.DATABASE.URL}

or

url: ${SPRING.DATABASE.URL}

Am I doing something wrong or missing? I appreciate your help, thank you.

Why not just set, e.g, `SPRING_DATSOURCE_URL` as the environment variable and skip the mapping between variable names? — Boris the Spider, Mar 29 '21 at 21:48
@BoristheSpider I've just tried right now and it gave me same error, again. — Goksenin Mert, Mar 29 '21 at 21:51
Then the environment variable is not being set. Without more details about what you’re trying to do it’s not clear how to help. For example I’m not sure what the Maven plug-in does given I presume you want the variables at runtime not build time. — Boris the Spider, Mar 29 '21 at 21:52
`.env` isn't supported by Spring Boot, even if you add a dependency that does support it. Environment variables are only available for those variables really available in the environment. So this simply won't work. — M. Deinum, Mar 30 '21 at 05:32

score 1 · Accepted Answer · edited Apr 06 '21 at 12:52

I recently ran in a similar issue and wanted to set environment variables via .env with application.yml - here is what I found out:

First, as you mentioned you have to add the java-dotenv dependency to pom.xml:

<dependency>
  <groupId>io.github.cdimascio</groupId>
  <artifactId>dotenv-java</artifactId>
  <version>2.2.0</version>
</dependency>

Then create your .env file in the root of your project (where pom.xml is located) and write your environment variables like e.g. ENV_PORT=8081.

Before you can use this environment variable, you have to "bind" the content of the .env file with Spring Boot when you start the app to make it globally available. According to this thread, this can be achieved by simply altering your Main entry point of spring (where you init the framework) like so:

@SpringBootApplication
public class MySpringApplication {

    public static void main(String[] args) {

        Map<String, Object> env = Dotenv.load()
                .entries()
                .stream()
                .collect(
                        Collectors.toMap(DotenvEntry::getKey, DotenvEntry::getValue));
        new SpringApplicationBuilder(MySpringApplication.class)
                .environment(new StandardEnvironment() {
                    @Override
                    protected void customizePropertySources(MutablePropertySources propertySources) {
                        super.customizePropertySources(propertySources);
                        propertySources.addLast(new MapPropertySource("dotenvProperties", env));
                    }
                }).run(args);
    }
}

That's it, now you can reference to your environment variables in application.yml like so:

server:
  port: ${ENV_PORT}

Hope this helps! If you are interested, here is also a full working example where I am using this approach.

You should not need the source code to read the env, it should work by default — nassim, Apr 06 '21 at 09:11

score 0 · Answer 2 · answered Mar 29 '21 at 22:00

java-dotenv you use has been renamed to kotlin-dotenv. If you look at its documentation, you'll see how it's used:

With Java

import io.github.cdimascio.dotenv.Dotenv;

Dotenv dotenv = Dotenv.load();

dotenv.get("MY_ENV_VAR1")

That's not what spring boot does - spring boot will not use any dotenv to fetch environment variables, so naturally the plugin won't work for your use case so .env files will not work.

If you start your app defining the environment variable when starting it app, it will work. To see how environment variables are passed using vscode, see this thread.

Spring Boot App does not recognize environment variables in application.yml file

2 Answers2