# How to Deploy Spring on Upsun Fixed with Redis

To activate Redis and then have it accessed by the Spring application already in Upsun Fixed, it is necessary to modify two files.

**Note**: 

This guide only covers the addition of a service configuration to an existing Spring project already configured to deploy on Upsun Fixed. Please see the [deployment guide](https://fixed.docs.upsun.com/guides/spring/deploy.md) for more detailed instructions for setting up app containers and initial projects.

## 1. Add the Redis service

In your [service configuration](https://fixed.docs.upsun.com/add-services.md),
include persistent Redis with a [valid supported version](https://fixed.docs.upsun.com/add-services/redis.md#persistent-redis):

      .platform/services.yaml

        ```yaml {}
data:
    type: redis-persistent:8.0
    disk: 256
```

## 2. Add the Redis relationship

In your [app configuration](https://fixed.docs.upsun.com/create-apps/app-reference/single-runtime-image.md), use the service name `searchelastic` to grant the application access to Elasticsearch via a relationship:

      .platform.app.yaml

        ```yaml {}
relationships:
    redisdata: "data:redis"
```

## 3. Export connection credentials to the environment

Connection credentials for Redis, like any service, are exposed to the application container through the `PLATFORM_RELATIONSHIPS` environment variable from the deploy hook onward. Since this variable is a base64 encoded JSON object of all of your project's services, you'll likely want a clean way to extract the information specific to Elasticsearch into it's own environment variables that can be used by Spring. On Upsun Fixed, custom environment variables can be defined programmatically in a `.environment` file using `jq` to do just that:

```bash  {location=".environment"}
export SPRING_REDIS_HOST="$(echo "$PLATFORM_RELATIONSHIPS" | base64 --decode | jq -r '.redisdata[0].host')"
export SPRING_REDIS_PORT="$(echo "$PLATFORM_RELATIONSHIPS" | base64 --decode | jq -r '.redisdata[0].port')"
export JAVA_OPTS="-Xmx$(jq .info.limits.memory /run/config.json)m -XX:+ExitOnOutOfMemoryError"
```

**Tip**: 

For access to more credentials options, check [Spring common application properties](https://docs.spring.io/spring-boot/docs/current/reference/html/application-properties.md)
and [binding from environment variables](https://docs.spring.io/spring-boot/docs/current/reference/html/spring-boot-features.md#features.external-config.typesafe-configuration-properties.relaxed-binding.environment-variables).

## 4. Connect to Redis

Commit that code and push. The Redis instance is ready to be connected from within the Spring application.

## Use Spring Data for Redis

You can use [Spring Data Redis](https://spring.io/projects/spring-data-mongodb) to use Redis with your app.
First, determine the MongoDB client using the [Java configuration reader library](https://github.com/platformsh/config-reader-java).

```java
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.GenericToStringSerializer;

@Configuration
public class RedisConfig {

    @Bean
    JedisConnectionFactory jedisConnectionFactory() {
        Config config = new Config();
        RedisSpring redis = config.getCredential("redis", RedisSpring::new);
        return redis.get();
    }

    @Bean
    public RedisTemplate redisTemplate() {
        final RedisTemplate template = new RedisTemplate();
        template.setConnectionFactory(jedisConnectionFactory());
        template.setValueSerializer(new GenericToStringSerializer(Object.class));
        return template;
    }

}
```