Redis (Object cache)

Redis is a multi-model database that allows you to store data in memory for high-performance data retrieval and key-value storage. Platform.sh supports two different Redis configurations:

Persistent: to set up fast persistent storage for your application
Ephemeral: to set up a non-persistent cache for your application

Use a framework

If you use one of the following frameworks, follow its guide:

For more implementation ideas, consult a template.

Supported versions

You can select the major and minor version.

Patch versions are applied periodically for bug fixes and the like. When you deploy your app, you always get the latest available patches.

Grid	Dedicated Gen 3	Dedicated Gen 2
7.2 7.0 6.2	7.2 7.0 6.2	7.0 6.2

Deprecated versions

The following versions are deprecated. They’re available, but they aren’t receiving security updates from upstream and aren’t guaranteed to work. They’ll be removed in the future, so migrate to one of the supported versions.

Grid	Dedicated Gen 3	Dedicated Gen 2
6.0 5.0 4.0 3.2 3.0 2.8	6.0 5.0 4.0 3.2 3.0 2.8	6.0 5.0 3.2

Note that versions 3.0 and higher support up to 64 different databases per instance of the service, while Redis 2.8 only supports a single database.

Service types

Depending on your needs, you can set up Redis as persistent or ephemeral.

Persistent Redis

By default, Redis is an ephemeral service that stores data in memory. This allows for fast data retrieval, but also means data can be lost when a container is moved or shut down.

To solve this issue, configure your Redis service as persistent. Persistent Redis stores data on a disk, restoring it if the container restarts.

To switch from persistent to ephemeral Redis, set up a new service with a different name.

Warning

Platform.sh sets the maximum amount of memory (maxmemory) Redis can use for the data set, and it cannot be amended. It is defined by comparing the following values and keeping the lower of the two:

Disk size/6 (based on a recommendation from Redis)
The amount of memory allocated to the service container

For instance, if your Redis container has 3072 MB of disk space and 1024 MB of memory, only 512 MB of RAM are actually available to the service (3072/6 = 512).

But if your Redis container has 3072 MB of disk space and 256 MB of memory, only 256 MB of RAM are actually available to the service (as per the container limit).

Usage example

1. Configure the service

To define the service, use the redis-persistent endpoint:

.platform/services.yaml

# The name of the service container. Must be unique within a project.
<SERVICE_NAME>:
    type: redis-persistent:<VERSION>

Note that changing the name of the service replaces it with a brand new service and all existing data is lost. Back up your data before changing the service.

2. Add the relationship

To define the relationship, use the redis endpoint :

.platform.app.yaml

# Relationships enable access from this app to a given service.
# The example below shows simplified configuration leveraging a default service
# (identified from the relationship name) and a default endpoint.
# See the Application reference for all options for defining relationships and endpoints.
relationships:
    <SERVICE_NAME>:

You can define <SERVICE_NAME> as you like, so long as it’s unique between all defined services and matches in both the application and services configuration.

The example above leverages default endpoint configuration for relationships. That is, it uses default endpoints behind-the-scenes, providing a relationship (the network address a service is accessible from) that is identical to the name of that service.

Depending on your needs, instead of default endpoint configuration, you can use explicit endpoint configuration.

With the above definition, the application container now has access to the service via the relationship <RELATIONSHIP_NAME> and its corresponding PLATFORM_RELATIONSHIPS environment variable.

For PHP, enable the extension for the service:

.platform.app.yaml

# PHP extensions.
runtime:
    extensions:
        - redis

Configuration example

Service definition

.platform/services.yaml

# The name of the service container. Must be unique within a project.
redis:
    type: redis-persistent:7.2
    disk: 256

App configuration

.platform.app.yaml

relationships:
    redis:

Use in app

To use the configured service in your app, add a configuration file similar to the following to your project.

package sh.platform.languages.sample;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import sh.platform.config.Config;
import sh.platform.config.Redis;

import java.util.Set;
import java.util.function.Supplier;

public class RedisSample implements Supplier<String> {

    @Override
    public String get() {
        StringBuilder logger = new StringBuilder();

        // Create a new config object to ease reading the Platform.sh environment variables.
        // You can alternatively use getenv() yourself.
        Config config = new Config();

        // The 'database' relationship is generally the name of primary database of an application.
        // It could be anything, though, as in the case here here where it's called "redis".
        Redis database = config.getCredential("redis", Redis::new);
        JedisPool dataSource = database.get();

        // Get a Redis Client
        final Jedis jedis = dataSource.getResource();

        // Set a values
        jedis.sadd("cities", "Salvador");
        jedis.sadd("cities", "London");
        jedis.sadd("cities", "São Paulo");

        // Read it back.
        Set<String> cities = jedis.smembers("cities");
        logger.append("<p>");
        logger.append("cities: " + cities);
        logger.append("</p>");
        jedis.del("cities");
        return logger.toString();
    }
}

const redis = require('redis');
const config = require("platformsh-config").config();
const { promisify } = require('util');

exports.usageExample = async function() {
    const credentials = config.credentials('redis');
    const client = redis.createClient(credentials.port, credentials.host);

    // The Redis client is not Promise-aware, so make it so.
    const redisGet = promisify(client.get).bind(client);
    const redisSet = promisify(client.set).bind(client);

    const key = 'Deploy day';
    const value = 'Friday';

    // Set a value.
    await redisSet(key, value);

    // Read it back.
    const test = await redisGet(key);

    return `Found value <strong>${test}</strong> for key <strong>${key}</strong>.`;
};

<?php

declare(strict_types=1);

use Platformsh\ConfigReader\Config;

// Create a new config object to ease reading the Platform.sh environment variables.
// You can alternatively use getenv() yourself.
$config = new Config();

// Get the credentials to connect to the Redis service.
$credentials = $config->credentials('redis');

try {
    // Connecting to Redis server.
    $redis = new Redis();
    $redis->connect($credentials['host'], $credentials['port']);

    $key = "Deploy day";
    $value = "Friday";

    // Set a value.
    $redis->set($key, $value);

    // Read it back.
    $test = $redis->get($key);

    printf('Found value <strong>%s</strong> for key <strong>%s</strong>.', $test, $key);

} catch (Exception $e) {
    print $e->getMessage();
}

from redis import Redis
from platformshconfig import Config


def usage_example():

    # Create a new config object to ease reading the Platform.sh environment variables.
    # You can alternatively use os.environ yourself.
    config = Config()

    # Get the credentials to connect to the Redis service.
    credentials = config.credentials('redis')

    try:
        redis = Redis(credentials['host'], credentials['port'])

        key = "Deploy day"
        value = "Friday"

        # Set a value
        redis.set(key, value)

        # Read it back
        test = redis.get(key)

        return 'Found value <strong>{0}</strong> for key <strong>{1}</strong>.'.format(test.decode("utf-8"), key)

    except Exception as e:
        return e

Ephemeral Redis

By default, Redis is an ephemeral service that serves as a non-persistent cache. Ephemeral Redis stores data only in memory and requires no disk space. When the service reaches its memory limit, it triggers a cache cleanup. To customize those cache cleanups, set up an eviction policy.

Make sure your app doesn’t rely on ephemeral Redis for persistent storage as it can cause issues. For example, if a container is moved during region maintenance, the deploy and post_deploy hooks don’t run and an app that treats the cache as permanent shows errors.

To prevent data from getting lost when a container is moved or shut down, you can use the persistent Redis configuration. Persistent Redis provides a cache with persistent storage.

Usage example

1. Configure the service

To define the service, use the redis endpoint:

.platform/services.yaml

# The name of the service container. Must be unique within a project.
<SERVICE_NAME>:
    type: redis:<VERSION>

Note that changing the name of the service replaces it with a brand new service and all existing data is lost. Back up your data before changing the service.

2. Add the relationship

To define the relationship, use the redis endpoint :

.platform.app.yaml

# Relationships enable access from this app to a given service.
# The example below shows simplified configuration leveraging a default service
# (identified from the relationship name) and a default endpoint.
# See the Application reference for all options for defining relationships and endpoints.
relationships:
    <SERVICE_NAME>:

You can define <SERVICE_NAME> as you like, so long as it’s unique between all defined services and matches in both the application and services configuration.

Depending on your needs, instead of default endpoint configuration, you can use explicit endpoint configuration.

With the above definition, the application container now has access to the service via the relationship <RELATIONSHIP_NAME> and its corresponding PLATFORM_RELATIONSHIPS environment variable.

For PHP, enable the extension for the service:

.platform.app.yaml

# PHP extensions.
runtime:
    extensions:
        - redis

Configuration example

Service definition

.platform/services.yaml

# The name of the service container. Must be unique within a project.
redis:
    type: redis:7.2
    disk: 256

App configuration

.platform.app.yaml

relationships:
    redis:

Use in app

To use the configured service in your app, add a configuration file similar to the following to your project.

package sh.platform.languages.sample;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import sh.platform.config.Config;
import sh.platform.config.Redis;

import java.util.Set;
import java.util.function.Supplier;

public class RedisSample implements Supplier<String> {

    @Override
    public String get() {
        StringBuilder logger = new StringBuilder();

        // Create a new config object to ease reading the Platform.sh environment variables.
        // You can alternatively use getenv() yourself.
        Config config = new Config();

        // The 'database' relationship is generally the name of primary database of an application.
        // It could be anything, though, as in the case here here where it's called "redis".
        Redis database = config.getCredential("redis", Redis::new);
        JedisPool dataSource = database.get();

        // Get a Redis Client
        final Jedis jedis = dataSource.getResource();

        // Set a values
        jedis.sadd("cities", "Salvador");
        jedis.sadd("cities", "London");
        jedis.sadd("cities", "São Paulo");

        // Read it back.
        Set<String> cities = jedis.smembers("cities");
        logger.append("<p>");
        logger.append("cities: " + cities);
        logger.append("</p>");
        jedis.del("cities");
        return logger.toString();
    }
}

const redis = require('redis');
const config = require("platformsh-config").config();
const { promisify } = require('util');

exports.usageExample = async function() {
    const credentials = config.credentials('redis');
    const client = redis.createClient(credentials.port, credentials.host);

    // The Redis client is not Promise-aware, so make it so.
    const redisGet = promisify(client.get).bind(client);
    const redisSet = promisify(client.set).bind(client);

    const key = 'Deploy day';
    const value = 'Friday';

    // Set a value.
    await redisSet(key, value);

    // Read it back.
    const test = await redisGet(key);

    return `Found value <strong>${test}</strong> for key <strong>${key}</strong>.`;
};

<?php

declare(strict_types=1);

use Platformsh\ConfigReader\Config;

// Create a new config object to ease reading the Platform.sh environment variables.
// You can alternatively use getenv() yourself.
$config = new Config();

// Get the credentials to connect to the Redis service.
$credentials = $config->credentials('redis');

try {
    // Connecting to Redis server.
    $redis = new Redis();
    $redis->connect($credentials['host'], $credentials['port']);

    $key = "Deploy day";
    $value = "Friday";

    // Set a value.
    $redis->set($key, $value);

    // Read it back.
    $test = $redis->get($key);

    printf('Found value <strong>%s</strong> for key <strong>%s</strong>.', $test, $key);

} catch (Exception $e) {
    print $e->getMessage();
}

from redis import Redis
from platformshconfig import Config


def usage_example():

    # Create a new config object to ease reading the Platform.sh environment variables.
    # You can alternatively use os.environ yourself.
    config = Config()

    # Get the credentials to connect to the Redis service.
    credentials = config.credentials('redis')

    try:
        redis = Redis(credentials['host'], credentials['port'])

        key = "Deploy day"
        value = "Friday"

        # Set a value
        redis.set(key, value)

        # Read it back
        test = redis.get(key)

        return 'Found value <strong>{0}</strong> for key <strong>{1}</strong>.'.format(test.decode("utf-8"), key)

    except Exception as e:
        return e

Multiple databases

Redis 3.0 and above support up to 64 databases. But you can’t set up different access rights to each database. When you set up a relationship connection, access to all of the databases is automatically granted.

The way to access a particular database depends on the client library you’re using:

Use the Redis select command:

<?php
$redis = new Redis();
$redis->connect(getenv('REDIS_HOST'), getenv('REDIS_PORT'));

$redis->select(0);       // switch to DB 0
$redis->set('x', '42');  // write 42 to x
$redis->move('x', 1);    // move to DB 1
$redis->select(1);       // switch to DB 1
$redis->get('x');        // returns 42

To manage thread safety, the Python library suggests using separate client instances for each database:

import os
from redis import Redis

database0 = Redis(host=os.getenv('REDIS_HOST'), port=os.getenv('REDIS_PORT'), db=0)
database1 = Redis(host=os.getenv('REDIS_HOST'), port=os.getenv('REDIS_PORT'), db=1)

Use the Redis select command:

const redis = require('redis');

const client = redis.createClient(process.env.CACHE_PORT, process.env.CACHE_HOST);

await client.SELECT(0);                  // switch to DB 0
await client.set('x', '42');             // write 42 to x
await client.MOVE('x', 1);               // move to DB 1
await client.SELECT(1);                  // switch to DB 1
const value = await client.get('x');     // returns 42

Relationship reference

Example information available through the PLATFORM_RELATIONSHIPS environment variable or by running platform relationships.

Note that the information about the relationship can change when an app is redeployed or restarted or the relationship is changed. So your apps should only rely on the PLATFORM_RELATIONSHIPS environment variable directly rather than hard coding any values.

{
  "username": null,
  "scheme": "redis",
  "service": "redis",
  "fragment": null,
  "ip": "123.456.78.90",
  "hostname": "azertyuiopqsdfghjklm.redis.service._.eu-1.platformsh.site",
  "port": 6379,
  "cluster": "azertyuiopqsdf-main-7rqtwti",
  "host": "redis.internal",
  "rel": "redis",
  "path": null,
  "query": [],
  "password": null,
  "type": "redis:7.2",
  "public": false,
  "host_mapped": false
}

The format of the relationship is identical whether your Redis service is ephemeral or persistent.

Eviction policy

When Redis reaches its memory limit, it triggers a cache cleanup. To customize those cache cleanups, set up an eviction policy such as the following:

.platform/services.yaml

# The name of the service container. Must be unique within a project.
redis:
    type: "redis:7.2"
    configuration:
        maxmemory_policy: allkeys-lfu

The following table presents the possible values:

Value	Policy description
`allkeys-lru`	Removes the oldest cache items first. This is the default policy when `maxmemory_policy` isn’t set.
`noeviction`	New items aren’t saved when the memory limit is reached.
`allkeys-lfu`	Removes least frequently used cache items first.
`volatile-lru`	Removes least recently used cache items with the `expire` field set to `true`.
`volatile-lfu`	Removes least frequently used cache items with the `expire` field set to `true`.
`allkeys-random`	Randomly removes cache items to make room for new data.
`volatile-random`	Randomly removes cache items with the `expire` field set to `true`.
`volatile-ttl`	Removes cache items with the `expire` field set to `true` and the shortest remaining `time-to -live` value.

For more information on the different policies, see the official Redis documentation.

Access your Redis service through the Redis CLI

After you’ve configured your Redis service, you can access it using the Redis CLI.

Retrieve the hostname and port you can connect to through the PLATFORM_RELATIONSHIPS environment variable. To do so, run the platform relationships command.

After you’ve retrieved the hostname and port, open an SSH session. To access your Redis service, run the following command:

redis-cli -h HOSTNAME -p PORT

If you have a Grid project, note that the CONFIG GET and CONFIG SET admin commands are restricted. To get the current configuration, run the following command:

redis-cli -h HOSTNAME -p PORT info

Use Redis as a handler for PHP sessions

A PHP session allows you to store different data for each user through a unique session ID. By default, PHP handles sessions using files. But you can use Redis as a session handler, which means Redis stores and retrieves the data saved into sessions.

To set up Redis as your session handler, add a configuration similar to the following:

.platform/services.yaml

# The name of the service container. Must be unique within a project.
redissessions:
    type: "redis-persistent:7.2"
    disk: 256

.platform.app.yaml

type: "php:8.3"

relationships:
    redissessions: 

variables:
    php:
        session.save_handler: redis
        session.save_path: "tcp://HOSTNAME:PORT"

web:
    locations:
        '/':
            root: 'web'
            passthru: '/index.php'

Integrated environments

Supported environments

Integrated environments

Supported environments

In-house observability tool

Third-party observability tools

Redis (Object cache)

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Use a framework

Supported versions

Deprecated versions

Service types

Persistent Redis

Warning

Usage example

1. Configure the service

2. Add the relationship

Configuration example

Service definition

App configuration

Use in app

Ephemeral Redis

Usage example

1. Configure the service

2. Add the relationship

Configuration example

Service definition

App configuration

Use in app

Multiple databases

Relationship reference

Eviction policy

Access your Redis service through the Redis CLI

Use Redis as a handler for PHP sessions

Is this page helpful?