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. Upsun 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

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. 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.

Relationship reference

For each service defined via a relationship to your application, Upsun automatically generates corresponding environment variables within your application container, in the $<RELATIONSHIP-NAME>_<SERVICE-PROPERTY> format. Here is example information available through the service environment variables themselves, or through the PLATFORM_RELATIONSHIPS environment variable.

Service environment variables
`PLATFORM_RELATIONSHIPS` environment variable

You can obtain the complete list of available service environment variables in your app container by running upsun ssh env.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 service environment variables directly rather than hard coding any values.

For some advanced use cases, you can use the PLATFORM_RELATIONSHIPS environment variable. The structure of the PLATFORM_RELATIONSHIPS environment variable can be obtained by running upsun relationships in your terminal:Here is an example of how to gather PLATFORM_RELATIONSHIPS environment variable information in a .environment file:

.environment

# Decode the built-in credentials object variable.
export RELATIONSHIPS_JSON="$(echo "$PLATFORM_RELATIONSHIPS" | base64 --decode)"

# Set environment variables for individual credentials.
export APP_REDIS_HOST="$(echo "$RELATIONSHIPS_JSON" | jq -r '.redis[0].host')"

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

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

Upsun 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: 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. Define the relationship

To define the relationship, use the redis endpoint :

Using default endpoints
Using explicit endpoints

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 SERVICE_NAME and its corresponding service environment variables.

You can define SERVICE_NAME and <RELATIONSHIP_NAME> as you like, so long as it’s unique between all defined services and relationships and matches in both the application and services configuration.The example above leverages explicit endpoint configuration for relationships.Depending on your needs, instead of explicit endpoint configuration, you can use default endpoint configuration.With the above definition, the application container now has access to the service via the relationship <RELATIONSHIP_NAME> and its corresponding service environment variables.

For PHP, enable the extension for the service:

Configuration example

Use in app

To use the configured service in your app, add a configuration file similar to the following to your project. This configuration defines a single application (myapp), whose source code exists in the <PROJECT_ROOT>/myapp directory.
myapp has access to the redis service, via a relationship whose name is identical to the service name (as per default endpoint configuration for relationships). From this, myapp can retrieve access credentials to the service through the relationship environment variables.

myapp/.environment

# Set environment variables for individual credentials.
# For more information, please visit https://docs.upsun.com/development/variables.html#service-environment-variables.
export CACHE_HOST="${REDIS_HOST}"
export CACHE_PORT="${REDIS_PORT}"
export CACHE_PASSWORD="${REDIS_PASSWORD}"
export CACHE_SCHEME="${REDIS_SCHEME}"

# Surface a Redis connection string for use in app.
export CACHE_URL="${CACHE_SCHEME}://${CACHE_PASSWORD}@${CACHE_HOST}:${CACHE_PORT}"

The above file — .environment in the myapp directory — is automatically sourced by Upsun into the runtime environment, so that the variable CACHE_URL can be used within the application to connect to the service. Note that CACHE_URL, and all Upsun service environment variables like REDIS_HOST, are environment-dependent. Unlike the build produced for a given commit, they can’t be reused across environments and only allow your app to connect to a single service instance on a single environment. A file very similar to this is generated automatically for your when using the upsun ify command to migrate a codebase to Upsun.

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: 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. Define the relationship

To define the relationship, use the redis endpoint :

Using default endpoints
Using explicit endpoints

For PHP, enable the extension for the service:

Configuration example

Use in app

myapp/.environment

# Set environment variables for individual credentials.
# For more information, please visit https://docs.upsun.com/development/variables.html#service-environment-variables.
export CACHE_HOST="${REDIS_HOST}"
export CACHE_PORT="${REDIS_PORT}"
export CACHE_PASSWORD="${REDIS_PASSWORD}"
export CACHE_SCHEME="${REDIS_SCHEME}"

# Surface a Redis connection string for use in app.
export CACHE_URL="${CACHE_SCHEME}://${CACHE_PASSWORD}@${CACHE_HOST}:${CACHE_PORT}"

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:

PHP
Python
Node.js

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.REDIS_PORT, process.env.REDIS_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

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: 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

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

Upsun CLI

Unlike the Redis CLI, connecting via the Upsun CLI does not require additional authentication steps if you are already authenticated in your terminal. Access your Redis service by running the command:

upsun redis

Redis CLI

Retrieve the hostname and port you can connect to through the PLATFORM_RELATIONSHIPS environment variable. To do so, run the upsun relationships command. After you’ve retrieved the hostname and port, open an SSH session. To access your Redis service, run the following command: 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:

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:

Exporting Data Persistent

This section applies only to persistent Redis services configured with type: redis-persistent. Ephemeral Redis (type: redis) stores data only in memory; its data does not need to be exported. The recommended approach is to use the BGSAVE command to write a point-in-time RDB snapshot to disk, then download it.

Open an SSH tunnel:

Terminal

upsun tunnel:single --relationship <RELATIONSHIP_NAME>

Trigger a background save and wait for it to complete:

Terminal

redis-cli -h 127.0.0.1 -p 30000 BGSAVE
# Poll until "Background saving terminated" appears:
redis-cli -h 127.0.0.1 -p 30000 LASTSAVE

Download the RDB dump file from the container:

Terminal

# Connect via SSH and locate the dump file
upsun ssh -- find / -name "dump.rdb" 2>/dev/null

# Copy it locally
upsun scp remote:/path/to/dump.rdb ./redis-dump.rdb

The .rdb file can be imported into any Redis or Valkey instance by placing it in the data directory and restarting the service.

Get Started

Core Concepts

Configure Apps & Services

Build, Deploy & Run

Manage Projects

Manage Environments

Manage Resources

Observability & Metrics

Integrations

Troubleshooting

Resources

Redis (Object cache)

Supported versions

Service types

Relationship reference

Persistent Redis

Warning

Usage example

1. Configure the service

2. Define the relationship

Configuration example

Use in app

Ephemeral Redis

Usage example

1. Configure the service

2. Define the relationship

Configuration example

Use in app

Multiple databases

Eviction policy

Access your Redis service

Upsun CLI

Redis CLI

Use Redis as a handler for PHP sessions

Exporting Data Persistent

Get Started

Core Concepts

Configure Apps & Services

Build, Deploy & Run

Manage Projects

Manage Environments

Manage Resources

Observability & Metrics

Integrations

Troubleshooting

Resources

​Supported versions

​Service types

​Relationship reference

​Persistent Redis

Warning

​Usage example

​1. Configure the service

​2. Define the relationship

​Configuration example

​Use in app

​Ephemeral Redis

​Usage example

​1. Configure the service

​2. Define the relationship

​Configuration example

​Use in app

​Multiple databases

​Eviction policy

​Access your Redis service

​Upsun CLI

​Redis CLI

​Use Redis as a handler for PHP sessions

​Exporting Data Persistent

Supported versions

Service types

Relationship reference

Persistent Redis

Usage example

1. Configure the service

2. Define the relationship

Configuration example

Use in app

Ephemeral Redis

Usage example

1. Configure the service

2. Define the relationship

Configuration example

Use in app

Multiple databases

Eviction policy

Access your Redis service

Upsun CLI

Redis CLI

Use Redis as a handler for PHP sessions

Exporting Data Persistent