Spring Cloud Bindings

The Spring Cloud Bindings library exposes a rich Java language binding for the Kubernetes Service Binding Specification. In addition, if opted-in, it configures Spring Boot application configuration properties appropriate for the type of binding encountered.

Features

• Java 17
• Spring Boot 3

For Spring Boot 2 compatibility, please have a look at the 1.x releases.

Library Usage

While less used, explicit binding access can be achieved through the Bindings type.

List<Binding> bindings = new Bindings().filterBindings("MySQL");
if (bindings.size() > 0) {
    Map<String, String> secret = bindings.get(0).getSecret();

    MariaDbDataSource dataSource = new MariaDbDataSource();
    dataSource.setServerName(secret.get("host"));
    dataSource.setPort(Integer.parseInt(secret.get("port")));
    dataSource.setDatabaseName(secret.get("database"));
    dataSource.setUserName(secret.get("username"));
    dataSource.setPassword(secret.get("password"));

    return dataSource;
}

Spring Boot Configuration

The more common usage of the library is opt-in automatic Spring Boot configuration. Setting the org.springframework.cloud.bindings.boot.enable=true System Property results in the following:

• Adds a PropertySource with a flattened representation (k8s.bindings.{name}.*) of the bindings.
• Adds a PropertySource with binding-specific Spring Boot configuration properties.

Auto-Configurations

Each auto-configuration is triggered by the type of binding. Each auto-configuration can be disabled using a System Property specific to that type and defaults to enable. Auto-configuration is disabled by default and can be enabled by setting the org.springframework.cloud.bindings.boot.enable System Property to true.

{<key>} indicates that the value is the contents of the secret with the given key.

ActiveMQ Artemis

Type: artemis Disable Property: org.springframework.cloud.bindings.boot.artemis.enable

Properties

Property	Value
spring.artemis.broker-url	{broker-url}
spring.artemis.mode	{mode}
spring.artemis.password	{password}
spring.artemis.user	{user}
spring.artemis.embedded.cluster-password	{embedded.cluster-password}
spring.artemis.embedded.data-directory	{embedded.data-directory}
spring.artemis.embedded.enabled	{embedded.enabled}
spring.artemis.embedded.persistent	{embedded.persistent}
spring.artemis.embedded.queues	{embedded.queues}
spring.artemis.embedded.server-id	{embedded.server-id}
spring.artemis.embedded.topics	{embedded.topics}
spring.artemis.pool.block-if-full	{pool.block-if-full}
spring.artemis.pool.block-if-full-timeout	{pool.block-if-full-timeout}
spring.artemis.pool.enabled	{pool.enabled}
spring.artemis.pool.idle-timeout	{pool.idle-timeout}
spring.artemis.pool.max-connections	{pool.max-connections}
spring.artemis.pool.max-sessions-per-connection	{pool.max-sessions-per-connection}
spring.artemis.pool.time-between-expiration-check	{pool.time-between-expiration-check}
spring.artemis.pool.use-anonymous-producers	{pool.use-anonymous-producers}

Cassandra

Type: cassandra Disable Property: org.springframework.cloud.bindings.boot.cassandra.enable

Properties

Property	Value
spring.cassandra.cluster-name	{cluster-name}
spring.cassandra.compression	{compression}
spring.cassandra.contact-points	{contact-points}
spring.cassandra.keyspace-name	{keyspace-name}
spring.cassandra.password	{password}
spring.cassandra.port	{port}
spring.cassandra.ssl	{ssl}
spring.cassandra.username	{username}
spring.cassandra.request.throttler.drain-interval	{request.throttler.drain-interval}
spring.cassandra.request.throttler.max-concurrent-requests	{request.throttler.max-concurrent-requests}
spring.cassandra.request.throttler.max-queue-size	{request.throttler.max-queue-size}
spring.cassandra.request.throttler.max-requests-per-second	{request.throttler.max-requests-per-second}

Couchbase

Type: couchbase Disable Property: org.springframework.cloud.bindings.boot.couchbase.enable

Properties

Property	Value
spring.couchbase.connection-string	{connection-string}
spring.data.couchbase.bucket-name	{bucket-name}
spring.couchbase.password	{password}
spring.couchbase.username	{username}

DB2 RDBMS

Type: db2 Disable Property: org.springframework.cloud.bindings.boot.db2.enable

Property	Value
spring.datasource.driver-class-name	com.ibm.db2.jcc.DB2Driver
spring.datasource.password	{password}
spring.datasource.url	{jdbc-url} or if not set then jdbc:db2://{host}:{port}/{database} (you must have host, port and database set or no mapping will occur)
spring.datasource.username	{username}
spring.r2dbc.url	{r2dbc-url} or if not set then r2dbc:db2://{host}:{port}/{database} (you must have host, port and database set or no mapping will occur)
spring.r2dbc.password	{password}
spring.r2dbc.username	{username}

Elasticsearch

Type: elasticsearch Disable Property: org.springframework.cloud.bindings.boot.elasticsearch.enable

Properties

Property	Value
spring.elasticsearch.password	{password}
spring.elasticsearch.uris	{uris}
spring.elasticsearch.username	{username}

Kafka

Type: kafka Disable Property: org.springframework.cloud.bindings.boot.kafka.enable

Property	Value
spring.kafka.bootstrap-servers	{bootstrap-servers}
spring.kafka.consumer.bootstrap-servers	{consumer.bootstrap-servers}
spring.kafka.producer.bootstrap-servers	{producer.bootstrap-servers}
spring.kafka.streams.bootstrap-servers	{streams.bootstrap-servers}

LDAP

Type: ldap Disable Property: org.springframework.cloud.bindings.boot.ldap.enable

Property	Value
spring.ldap.base	{base}
spring.ldap.password	{password}
spring.ldap.urls	{urls}
spring.ldap.username	{username}

MongoDB

Type: mongodb Disable Property: org.springframework.cloud.bindings.boot.mongodb.enable

Property	Value
spring.data.mongodb.authentication-database	{authentication-database}
spring.data.mongodb.database	{database}
spring.data.mongodb.gridfs.database"	{grid-fs-database}
spring.data.mongodb.host	{host}
spring.data.mongodb.password	{password}
spring.data.mongodb.port	{port}
spring.data.mongodb.uri	{uri}
spring.data.mongodb.username	{username}

MySQL RDBMS

Type: mysql Disable Property: org.springframework.cloud.bindings.boot.mysql.enable

Property	Value
spring.datasource.driver-class-name	org.mariadb.jdbc.Driver or com.mysql.cj.jdbc.Driver depending on classpath
spring.datasource.password	{password}
spring.datasource.url	{jdbc-url} or if not set then jdbc:mysql://{host}:{port}/{database} or jdbc:mariadb://{host}:{port}/{database} depending on classpath (you must have host, port and database set or no mapping will occur)
spring.datasource.username	{username}
spring.r2dbc.url	{r2dbc-url} or if not set then r2dbc:mysql://{host}:{port}/{database} or r2dbc:mariadb//{host}:{port}/{database} depending on classpath (you must have host, port and database set or no mapping will occur)
spring.r2dbc.password	{password}
spring.r2dbc.username	{username}

Note: Libraries on the classpath are examined for the purpose of evaluating the appropriate jdbc and r2dbc URLs. The existence of both MySQL and MariaDB libraries on the classpath is not supported and may lead to non-deterministic results.

Neo4J

Type: neo4j Disable Property: org.springframework.cloud.bindings.boot.neo4j.enable

Properties

Property	Value
spring.neo4j.uri	{uri}
spring.neo4j.authentication.username	{username}
spring.neo4j.authentication.password	{password}

Oracle RDBMS

Type: oracle Disable Property: org.springframework.cloud.bindings.boot.oracle.enable

Property	Value
spring.datasource.driver-class-name	oracle.jdbc.OracleDriver
spring.datasource.password	{password}
spring.datasource.url	{jdbc-url} or if not set then jdbc:oracle://{host}:{port}/{database} (you must have host, port and database set or no mapping will occur)
spring.datasource.username	{username}
spring.r2dbc.url	{r2dbc-url} or if not set then r2dbc:oracle://{host}:{port}/{database} (you must have host, port and database set or no mapping will occur)
spring.r2dbc.password	{password}
spring.r2dbc.username	{username}

PostgreSQL RDBMS

Type: postgresql Disable Property: org.springframework.cloud.bindings.boot.postgresql.enable

Property	Value
spring.datasource.driver-class-name	org.postgresql.Driver
spring.datasource.password	{password}
spring.datasource.url	{jdbc-url} or if not set then jdbc:postgresql://{host}:{port}/{database}. If a binding for {sslmode}, {sslrootcert}, or {options} are set, the value is appended as properties to the generated URL (you must have host, port and database set or no mapping will occur)
spring.datasource.username	{username}
spring.r2dbc.url	{r2dbc-url} or if not set then r2dbc:postgresql://{host}:{port}/{database}. If a binding for {sslmode}, {sslrootcert}, or {options} are set, the value is appended as properties to the generated URL (you must have host, port and database set or no mapping will occur)
spring.r2dbc.password	{password}
spring.r2dbc.username	{username}

RabbitMQ

Type: rabbitmq Disable Property: org.springframework.cloud.bindings.boot.rabbitmq.enable

Property	Value
spring.rabbitmq.addresses	{addresses}
spring.rabbitmq.host	{host}
spring.rabbitmq.password	{password}
spring.rabbitmq.port	{port}
spring.rabbitmq.username	{username}
spring.rabbitmq.virtual-host	{virtual-host}

Redis

Type: redis Disable Property: org.springframework.cloud.bindings.boot.redis.enable

Properties

Property	Value
spring.data.redis.client-name	{client-name}
spring.data.redis.cluster.max-redirects	{cluster.max-redirects}
spring.data.redis.cluster.nodes	{cluster.nodes}
spring.data.redis.database	{database}
spring.data.redis.host	{host}
spring.data.redis.password	{password}
spring.data.redis.port	{port}
spring.data.redis.sentinel.master	{sentinel.master}
spring.data.redis.sentinel.nodes	{sentinel.nodes}
spring.data.redis.ssl	{ssl}
spring.data.redis.url	{url}

SAP Hana

Type: hana Disable Property: org.springframework.cloud.bindings.boot.hana.enable

Property	Value
spring.datasource.driver-class-name	com.sap.db.jdbc.Driver
spring.datasource.password	{password}
spring.datasource.url	{jdbc-url} or if not set then jdbc:sap://{host}:{port}/{database} (you must have host, port and database set or no mapping will occur)
spring.datasource.username	{username}
spring.r2dbc.url	{r2dbc-url} or if not set then r2dbc:sap://{host}:{port}/{database} (you must have host, port and database set or no mapping will occur)
spring.r2dbc.password	{password}
spring.r2dbc.username	{username}

SCS Config Server

Type: config Disable Property: org.springframework.cloud.bindings.boot.config.enable

Property	Value
spring.cloud.config.uri	{uri}
spring.cloud.config.client.oauth2.clientId	{client-id}
spring.cloud.config.client.oauth2.clientSecret	{client-secret}
spring.cloud.config.client.oauth2.accessTokenUri	{access-token-uri}
spring.cloud.config.tls.enabled	true when {tls.crt} and {tls.key} are set
spring.cloud.config.tls.key-store	derived from {tls.crt} and {tls.key}
spring.cloud.config.tls.key-store-type	"PKCS12" when {tls.crt} and {tls.key} are set
spring.cloud.config.tls.key-store-password	random string when {tls.crt} and {tls.key} are set
spring.cloud.config.tls.key-alias	"config" when {tls.crt} and {tls.key} are set
spring.cloud.config.tls.key-password	"" when {tls.crt} and {tls.key} are set
spring.cloud.config.tls.trust-store	derived from {ca.crt} when it is set
spring.cloud.config.tls.trust-store-type	"PKCS12" when {ca.crt} is set
spring.cloud.config.tls.trust-store-password	random string when {ca.crt} is set

SCS Eureka

Type: eureka Disable Property: org.springframework.cloud.bindings.boot.eureka.enable

Property	Value
eureka.client.oauth2.client-id	{client-id}
eureka.client.oauth2.access-token-uri	{access-token-uri}
eureka.client.region	default
eureka.client.serviceUrl.defaultZone	{uri}/eureka/
eureka.client.tls.enabled	true when {ca.crt} is set
eureka.client.tls.trust-store	derived from {ca.crt}
eureka.client.tls.trust-store-type	"PKCS12" when {ca.crt} is set
eureka.client.tls.trust-store-password	random string when {ca.crt} is set
eureka.instance.preferIpAddress	true when {ca.crt} is set1
eureka.client.tls.key-alias	"eureka" when {ca.crt}, {tls.crt} and {tls.key} are set
eureka.client.tls.key-store	derived from {tls.crt} and {tls.key}
eureka.client.tls.key-store-type	"PKCS12" when {ca.crt}, {tls.crt} and {tls.key} are set
eureka.client.tls.key-store-password	random string when {ca.crt}, {tls.crt} and {tls.key} are set
eureka.client.tls.key-password	"" when {ca.crt}, {tls.crt} and {tls.key} are set

Spring Security OAuth2

Type: oauth2 Disable Property: org.springframework.cloud.bindings.boot.oauth2.enable

Property	Value
spring.security.oauth2.client.registration.{name}.client-id	{client-id}
spring.security.oauth2.client.registration.{name}.client-secret	{client-secret}
spring.security.oauth2.client.registration.{name}.provider	{provider}
spring.security.oauth2.client.registration.{name}.client-name	{client-name}
spring.security.oauth2.client.registration.{name}.client-authentication-method	{client-authentication-method}
spring.security.oauth2.client.registration.{name}.authorization-grant-type	{authorization-grant-type} or if not set then {authorization-grant-types} if it contains only one value (comma-separated)
spring.security.oauth2.client.registration.{name}.redirect-uri	{redirect-uri} or if not set then {redirect-uris} if it contains only one value (comma-separated)
spring.security.oauth2.client.registration.{name}.scope	{scope}
spring.security.oauth2.client.provider.{provider}.issuer-uri	{issuer-uri}
spring.security.oauth2.client.provider.{provider}.authorization-uri	{authorization-uri}
spring.security.oauth2.client.provider.{provider}.token-uri	{token-uri}
spring.security.oauth2.client.provider.{provider}.user-info-uri	{user-info-uri}
spring.security.oauth2.client.provider.{provider}.user-info-authentication-method	{user-info-authentication-method}
spring.security.oauth2.client.provider.{provider}.jwk-set-uri	{jwk-set-uri}
spring.security.oauth2.client.provider.{provider}.user-name-attribute	{user-name-attribute}

SQLServer RDBMS

Type: sqlserver Disable Property: org.springframework.cloud.bindings.boot.sqlserver.enable

Property	Value
spring.datasource.driver-class-name	com.microsoft.sqlserver.jdbc.SQLServerDriver
spring.datasource.password	{password}
spring.datasource.url	jdbc:sqlserver://{host}:{port}/{database} (you must have host, port and database set or no mapping will occur)
spring.datasource.username	{username}
spring.r2dbc.url	{r2dbc-url} or if not set then r2dbc:sqlserver://{host}:{port}/{database} (you must have host, port and database set or no mapping will occur)
spring.r2dbc.password	{password}
spring.r2dbc.username	{username}

Vault

Type: vault Disable Property: org.springframework.cloud.bindings.boot.vault.enable

Any Provider:

Property	Value
spring.cloud.vault.authentication	{authentication-method}
spring.cloud.vault.namespace	{namespace}
spring.cloud.vault.uri	{uri}

If {authentication-method} is equal to approle:

Property	Value
spring.cloud.vault.app-role.app-role-path	{app-role-path}
spring.cloud.vault.app-role.role-id	{role-id}
spring.cloud.vault.app-role.role	{role}
spring.cloud.vault.app-role.secret-id	{secret-id}

If {authentication-method} is equal to aws_ec2:

Property	Value
spring.cloud.vault.aws-ec2.aws-ec2-path	{aws-ec2-path}
spring.cloud.vault.aws-ec2.identity-document	{aws-ec2-instance-identity-document}
spring.cloud.vault.aws-ec2.nonce	{nonce}
spring.cloud.vault.aws-ec2.role	{role}

If {authentication-method} is equal to aws_iam:

Property	Value
spring.cloud.vault.aws-iam.aws-path	{aws-path}
spring.cloud.vault.aws-iam.endpoint-uri	{aws-sts-endpoint-uri}
spring.cloud.vault.aws-iam.role	{role}
spring.cloud.vault.aws-iam.server-name	{aws-iam-server-name}

If {authentication-method} is equal to azure_msi:

Property	Value
spring.cloud.vault.azure-msi.azure-path	{azure-path}
spring.cloud.vault.azure-msi.role	{role}
spring.cloud.vault.azure-msi.metadata-service	{metadata-service}
spring.cloud.vault.azure-msi.identity-token-service	{identity-token-service}

If {authentication-method} is equal to cert:

Property	Value
spring.cloud.vault.ssl.cert-auth-path	{cert-auth-path}
spring.cloud.vault.ssl.key-store-password	{key-store-password}
spring.cloud.vault.ssl.key-store	${SERVICE_BINDING_ROOT}/{name}/keystore.jks
spring.cloud.vault.ssl.trust-store	${SERVICE_BINDING_ROOT}/{name}/truststore.jks
spring.cloud.vault.ssl.trust-store-password	{trust-store-password}

If {authentication-method} is equal to cubbyhole:

Property	Value
spring.cloud.vault.token	{token}

If {authentication-method} is equal to gcp_gce:

Property	Value
spring.cloud.vault.gcp-gce.gcp-path	{gcp-path}
spring.cloud.vault.gcp-gce.role	{role}
spring.cloud.vault.gcp-gce.service-account	{gcp-service-account}

If {authentication-method} is equal to gcp_iam:

Property	Value
spring.cloud.vault.gcp-iam.credentials.encoded-key	{encoded-key}
spring.cloud.vault.gcp-iam.credentials.location	${SERVICE_BINDING_ROOT}/{name}/credentials.json
spring.cloud.vault.gcp-iam.gcp-path	{gcp-path}
spring.cloud.vault.gcp-iam.jwt-validity	{jwt-validity}
spring.cloud.vault.gcp-iam.project-id	{gcp-project-id}
spring.cloud.vault.gcp-iam.role	{role}
spring.cloud.vault.gcp-iam.service-account	{gcp-service-account} Spring Boot 2
spring.cloud.vault.gcp-iam.service-account-id	{gcp-service-account} Spring Boot 3

If {authentication-method} is equal to kubernetes:

Property	Value
spring.cloud.vault.kubernetes.role	{role}
spring.cloud.vault.kubernetes.kubernetes-path	{kubernetes-path}
spring.cloud.vault.kubernetes.kubernetes-service-account-token-file	{kubernetes-service-account-token-file} Spring Boot 3

If {authentication-method} is equal to token:

Property	Value
spring.cloud.vault.token	{token}

Wavefront

Type: wavefront Disable Property: org.springframework.cloud.bindings.boot.wavefront.enable

Property	Value
management.wavefront.api-token	{api-token}
management.wavefront.uri	{uri}

Extending Spring Boot Configuration

Consumers can extend the BindingSpecificEnvironmentPostProcessor with support for additional bindings by registering additional implementations of the BindingsPropertiesProcessor.

Within the process method, custom processors should make desired modifications to the application properties, using the contents of the bindings to compute property values as appropriate. Custom processors are strongly encouraged to use the type of each binding to filter for bindings intended for that processor.

Below is an example that processes a single binding of type myservice. If such a binding exists this processor sets my.service.enabled=true and sets my.service.uri to the value of uri found in the binding secret.

package com.example;


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 final class MyServiceBindingsPropertiesProcessor implements BindingsPropertiesProcessor {

    public static final String TYPE = "myservice";

    @Override
    public void process(Environment environment, Bindings bindings, Map<String, Object> properties) {
        if (!environment.getProperty("com.example.bindings.myservice.enable", Boolean.class, true)) {
            return;
        }
        List<Binding> myBindings = bindings.filterBindings(TYPE);
        if (myBindings.size() == 0) {
            return;
        }
        properties.put("my.service.uri", myBindings.get(0).getSecret().get("uri"));
        properties.put("my.service.enabled", true);
    }

}

These lines from the above example allow users to set com.example.bindings.myservice.enable=false to disable the processor entirely:

        if (!environment.getProperty("com.example.bindings.myservice.enable", Boolean.class, true)) {
            return;
        }

You must add an entry in META_INF/spring.factories so that your custom processor can be discovered.

org.springframework.cloud.bindings.boot.BindingsPropertiesProcessor=com.example.MyServiceBindingsPropertiesProcessor

License

This buildpack is released under version 2.0 of the Apache License.

Footnotes

1. Note that eureka.instance.perferIpAddress will not be overwritten by the Eureka auto-configuration if it is already set in the environment. Applications wishing to set an explicit endpoint with eureka.instance.host can set eureka.instance.perferIpAddress to false and it will not be overwritten. ↩