Accessing Spring Cloud Bindings' Bindings without Containerizing

· 6 min read

This post describes how to use Spring Cloud Bindings without containerizing. The flow is as follows:

For Service Bindings themselves, see:

https://servicebinding.io/

Set the required System Property

When starting Spring Boot, set this System Property:

org.springframework.cloud.bindings.boot.enable=true

When using IntelliJ or the like, configure it as follows: Run → Edit Configurations... and add the setting below.

Set the SERVICE_BINDING_ROOT environment variable

Set the starting directory for Service Bindings.

When using IntelliJ or the like, configure it as follows: Run → Edit Configurations... and add the setting below.

Update pom.xml

Add the required dependencies as follows. Update the value of <spring-cloud-bindings.version> as appropriate.

  <properties>
    ...
    <spring-cloud-bindings.version>1.10.0</spring-cloud-bindings.version>
    ...
  </properties>
  <dependencies>
      ...
      <dependency>
          <groupId>org.springframework.cloud</groupId>
          <artifactId>spring-cloud-bindings</artifactId>
          <version>${spring-cloud-bindings.version}</version>
      </dependency>
    　...
  </dependencies>
  <repositories>
        ...
        <repository>
            <id>spring-releases</id>
            <url>https://repo.spring.io/release/</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
        ...
  </repositories>
  <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.springframework.cloud</groupId>
                            <artifactId>spring-cloud-bindings</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
  </build>

Note that without the block below, containerizing later collides with the Spring Boot buildpack's update behavior and errors out.

<configuration>
    <excludes>
        <exclude>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-bindings</artifactId>
        </exclude>
    </excludes>
</configuration>

(Optional) Create your own Bindings

With everything configured so far, you can now create your own Bindings. For example, prepare code like this:

package jp.vmware.tanzu.twitterwordclouddemo.utils;

import org.jetbrains.annotations.NotNull;
import org.springframework.cloud.bindings.Binding;
import org.springframework.cloud.bindings.Bindings;
import org.springframework.cloud.bindings.boot.BindingsPropertiesProcessor;
import org.springframework.core.env.Environment;

import java.util.List;
import java.util.Map;

public class TwitterBindingsPropertiesProcessor implements BindingsPropertiesProcessor {

	public static final String TYPE = "twitter";

	@Override
	public void process(Environment environment, @NotNull Bindings bindings, @NotNull Map<String, Object> properties) {
		if (!environment.getProperty("jp.vmware.tanzu.bindings.boot.twitter.enable", Boolean.class, true)) {
			return;
		}
		List<Binding> myBindings = bindings.filterBindings(TYPE);
		if (myBindings.size() == 0) {
			return;
		}
		properties.put("twitter.bearer.token", myBindings.get(0).getSecret().get("bearer-token"));
	}

}

Additionally, create META-INF/spring.factories like this:

org.springframework.cloud.bindings.boot.BindingsPropertiesProcessor=jp.vmware.tanzu.twitterwordclouddemo.utils.TwitterBindingsPropertiesProcessor

Then place a directory structure like the following into the directory set as SERVICE_BINDING_ROOT, and Service Bindings become active at startup.