Spring Cloud Bindings

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

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 (cnb.bindings.{name}.{metadata,secret}.*) of the bindings.
• Adds a PropertySource with binding-specific Spring Boot configuration properties.

Auto-Configurations

Each auto-configuration is triggered by the kind of binding. Each auto-configuration can be disabled using a System Property specific to that kind 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.

Cassandra

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

Property	Value
spring.data.cassandra.cluster-name	{secret/cluster-name}
spring.data.cassandra.compression	{secret/compression}
spring.data.cassandra.contact-points	{secret/contact-points}
spring.data.cassandra.keyspace-name	{secret/keyspace-name}
spring.data.cassandra.password	{secret/password}
spring.data.cassandra.port	{secret/port}
spring.data.cassandra.ssl	{secret/ssl}
spring.data.cassandra.username	{secret/username}

Couchbase

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

Property	Value
spring.couchbase.bootstrap-hosts	{secret/bootstrap-hosts}
spring.couchbase.bucket.name	{secret/bucket.name}
spring.couchbase.bucket.password	{secret/bucket.passsword}
spring.couchbase.env.bootstrap.http-direct-port	{secret/env.bootstrap.http-direct-port}
spring.couchbase.env.bootstrap.http-ssl-port	{secret/env.bootstrap.http-ssl-port}
spring.couchbase.password	{secret/password}
spring.couchbase.username	{secret/username}

DB2 RDBMS

Kind: 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	{secret/password}
spring.datasource.url	jdbc:db2://{secret/host}:{secret/port}/{secret/database}
spring.datasource.username	{secret/username}
spring.r2dbc.url	r2dbc:db2://{secret/host}:{secret/port}/{secret/database}
spring.r2dbc.password	{secret/password}
spring.r2dbc.username	{secret/username}

Elasticsearch

Kind: Elasticsearch Disable Property: org.springframework.cloud.bindings.boot.elasticsearch.enable

Property	Value
spring.data.elasticsearch.client.reactive.endpoints	{secret/endpoints}
spring.data.elasticsearch.client.reactive.password	{secret/password}
spring.data.elasticsearch.client.reactive.use-ssl	{secret/use-ssl}
spring.data.elasticsearch.client.reactive.username	{secret/username}
spring.elasticsearch.jest.password	{secret/password}
spring.elasticsearch.jest.proxy.host	{secret/proxy.host}
spring.elasticsearch.jest.proxy.port	{secret/proxy.port}
spring.elasticsearch.jest.username	{secret/username}
spring.elasticsearch.rest.password	{secret/password}
spring.elasticsearch.rest.uris	{secret/uris}
spring.elasticsearch.rest.username	{secret/username}

Kafka

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

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

LDAP

Kind: LDAP Disable Property: org.springframework.cloud.bindings.boot.ldap.enable

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

MongoDB

Kind: MongoDB Disable Property: org.springframework.cloud.bindings.boot.mongodb.enable

Property	Value
spring.mongodb.authentication-database	{secret/authentication-database}
spring.mongodb.database	{secret/database}
spring.mongodb.grid-fs-database	{secret/grid-fs-database}
spring.mongodb.host	{secret/host}
spring.mongodb.password	{secret/password}
spring.mongodb.port	{secret/port}
spring.mongodb.uri	{secret/uri}
spring.mongodb.username	{secret/username}

MySQL RDBMS

Kind: 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	{secret/password}
spring.datasource.url	jdbc:mysql://{secret/host}:{secret/port}/{secret/database}
spring.datasource.username	{secret/username}
spring.r2dbc.url	r2dbc:mysql://{secret/host}:{secret/port}/{secret/database}
spring.r2dbc.password	{secret/password}
spring.r2dbc.username	{secret/username}

Neo4J

Kind: Neo4J Disable Property: org.springframework.cloud.bindings.boot.neo4j.enable

Property	Value
spring.data.neo4j.password	{secret/password}
spring.data.neo4j.uri	{secret/uri}
spring.data.neo4j.username	{secret/username}

Oracle RDBMS

Kind: Oracle Disable Property: org.springframework.cloud.bindings.boot.oracle.enable

Property	Value
spring.datasource.driver-class-name	oracle.jdbc.OracleDriver
spring.datasource.password	{secret/password}
spring.datasource.url	jdbc:oracle://{secret/host}:{secret/port}/{secret/database}
spring.datasource.username	{secret/username}
spring.r2dbc.url	r2dbc:oracle://{secret/host}:{secret/port}/{secret/database}
spring.r2dbc.password	{secret/password}
spring.r2dbc.username	{secret/username}

PostgreSQL RDBMS

Kind: PostgreSQL Disable Property: org.springframework.cloud.bindings.boot.postgresql.enable

Property	Value
spring.datasource.driver-class-name	org.postgresql.Driver
spring.datasource.password	{secret/password}
spring.datasource.url	jdbc:postgres://{secret/host}:{secret/port}/{secret/database}
spring.datasource.username	{secret/username}
spring.r2dbc.url	r2dbc:postgres://{secret/host}:{secret/port}/{secret/database}
spring.r2dbc.password	{secret/password}
spring.r2dbc.username	{secret/username}

RabbitMQ RDBMS

Kind: RabbitMQ Disable Property: org.springframework.cloud.bindings.boot.rabbitmq.enable

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

Redis RDBMS

Kind: Redis Disable Property: org.springframework.cloud.bindings.boot.redis.enable

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

SCS Config Server

Kind: Config Disable Property: org.springframework.cloud.bindings.boot.config.enable

Property	Value
spring.cloud.config.uri	{secret/uri}
spring.cloud.config.client.oauth2.clientId	{secret/client-id}
spring.cloud.config.client.oauth2.clientSecret	{secret/client-secret}
spring.cloud.config.client.oauth2.accessTokenUri	{secret/access-token-uri}

SCS Eureka

Kind: Eureka Disable Property: org.springframework.cloud.bindings.boot.eureka.enable

Property	Value
eureka.client.oauth2.client-id	{secret/client-id}
eureka.client.oauth2.access-token-uri	{secret/access-token-uri}
eureka.client.region	default
eureka.client.serviceUrl.defaultZone	{secret/uri}/eureka/

Spring Security OAuth2

Kind: OAuth2 Disable Property: org.springframework.cloud.bindings.boot.oauth2.enable

Property	Value
spring.security.oauth2.client.registration.{name}.client-id	{secret/client-id}
spring.security.oauth2.client.registration.{name}.client-secret	{secret/client-secret}
spring.security.oauth2.client.registration.{name}.provider	{metadata/provider}
spring.security.oauth2.client.provider.{metadata/provider}.issuer-uri	{secret/issuer-uri}
spring.security.oauth2.client.provider.{metadata/provider}.authorization-uri	{secret/authorization-uri}
spring.security.oauth2.client.provider.{metadata/provider}.token-uri	{secret/token-uri}
spring.security.oauth2.client.provider.{metadata/provider}.user-info-uri	{secret/user-info-uri}
spring.security.oauth2.client.provider.{metadata/provider}.user-info-authentication-method	{secret/user-info-authentication-method}
spring.security.oauth2.client.provider.{metadata/provider}.jwk-set-uri	{secret/jwk-set-uri}
spring.security.oauth2.client.provider.{metadata/provider}.user-name-attribute	{secret/user-name-attribute}

SQLServer RDBMS

Kind: 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	{secret/password}
spring.datasource.url	jdbc:sqlserver://{secret/host}:{secret/port}/{secret/database}
spring.datasource.username	{secret/username}
spring.r2dbc.url	r2dbc:sqlserver://{secret/host}:{secret/port}/{secret/database}
spring.r2dbc.password	{secret/password}
spring.r2dbc.username	{secret/username}

Vault

Kind: Vault Disable Property: org.springframework.cloud.bindings.boot.vault.enable

Any Provider:

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

If {secret/method} is equal to approle:

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

If {secret/method} is equal to aws_ec2:

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

If {secret/method} is equal to aws_iam:

Property	Value
spring.cloud.vault.aws-iam.aws-path	{secret/aws-path}
spring.cloud.vault.aws-iam.endpoint-uri	{secret/endpoint-uri}
spring.cloud.vault.aws-iam.role	{secret/token}
spring.cloud.vault.aws-iam.server-id	{secret/server-id}

If {secret/method} is equal to azure_msi:

Property	Value
spring.cloud.vault.azure-msi.azure-path	{secret/azure-path}
spring.cloud.vault.azure-msi.role	{secret/role}

If {secret/method} is equal to cert:

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

If {secret/method} is equal to cubbyhole:

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

If {secret/method} is equal to gcp_gce:

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

If {secret/method} is equal to gcp_iam:

Property	Value
spring.cloud.vault.gcp-iam.credentials.encoded-key	{secret/encoded-key}
spring.cloud.vault.gcp-iam.credentials.location	${CNB_BINDINGS}/{name}/secret/credentials.json
spring.cloud.vault.gcp-iam.gcp-path	{secret/gcp-path}
spring.cloud.vault.gcp-iam.jwt-validity	{secret/jwt-validity}
spring.cloud.vault.gcp-iam.project-id	{secret/project-id}
spring.cloud.vault.gcp-iam.role	{secret/role}
spring.cloud.vault.gcp-iam.service-account-id	{secret/service-account-id}

If {secret/method} is equal to kubernetes:

Property	Value
spring.cloud.vault.kubernetes.kubernetes-path	{secret/kubernetes-path}
spring.cloud.vault.kubernetes.role	{secret/role}

If {secret/method} is equal to token:

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

Wavefront

Kind: Wavefront Disable Property: org.springframework.cloud.bindings.boot.wavefront.enable

Property	Value
management.metrics.export.wavefront.api-token	{secret/api-token}
management.metrics.export.wavefront.uri	{secret/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 kind of each binding to filter for bindings intended for that processor.

Below is an example that processes a single binding of kind 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 KIND = "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(KIND);
        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.