Storage

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Databases

Flipt supports SQLite, PostgreSQL, CockroachDB and MySQL databases.

SQLite is enabled by default for simplicity, however you should use PostgreSQL, MySQL, or CockroachDB if you intend to run multiple copies of Flipt in a high availability configuration.

The database connection can be configured as follows:

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SQLite

db:
  # file: informs flipt to use SQLite
  url: file:/var/opt/flipt/flipt.db

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PostgreSQL

db:
  url: postgres://postgres@localhost:5432/flipt?sslmode=disable

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CockroachDB

db:
  url: cockroach://root@localhost:26257/flipt?sslmode=disable

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MySQL

db:
  url: mysql://mysql@localhost:3306/flipt

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Migrations

From time to time the Flipt database must be updated with new schema. To accomplish this, Flipt includes a migrate command that will run any pending database migrations for you.

If Flipt is started and there are pending migrations, you will see the following error in the console:

migrations pending, please backup your database and run `flipt migrate`

If it is your first run of Flipt, all migrations will automatically be run before starting the Flipt server.

If running Flipt via Docker, you can run the migrations in a separate container before starting Flipt by running:

docker run -it -v $HOME/flipt:/var/opt/flipt flipt/flipt:latest /bin/sh -c './flipt migrate'

If you don’t use mounted volumes to persist your data, your data will be lost when the migration container exits, having no effect on your Flipt instance!

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Import/Export

Flipt supports importing and exporting your feature flag data since v0.13.0.

Prior to Flipt v1.20.0 import and export ran directly against the backing database. Since v1.20.0 you can now alternatively perform these operations through Flipt’s API. Both flipt import and flipt export support the --address and --token flags to enable this behaviour.

flipt import --address http://flipt.my.org --token static-api-token

flipt export --address grpc://flipt.my.org:9000

Both HTTP and gRPC are supported by the --address flag.

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Import

To import previously exported Flipt data, use the flipt import command. You can import either from a file or from STDIN.

To import from STDIN, Flipt requires the --stdin flag:

cat flipt.yaml | flipt import --stdin

If not importing using --stdin, Flipt requires the file to be imported as an argument:

flipt import flipt.yaml

By default, Flipt will import into the default namespace. Use the flag --namespace to import into a different namespace.

flipt import --namespace production flipt.yaml

A namespace must exist before your import into it. For convenience, you can supply --create-namespace in order for Flipt to automatically create the namespace if it does not already exist.

flipt import --namespace production --create-namespace flipt.yaml

This command supports the --drop flag that will drop all of the data in your Flipt database tables before importing. This is to ensure that no data collisions occur during the import.

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Export

To export Flipt data, use the flipt export command.

By default, export will output to STDOUT:

$ flipt export

flags:
- key: new-contact-page
  name: New Contact Page
  description: Show users our Beta contact page
  enabled: true
  variants:
  - key: blue
    name: Blue
  - key: green
    name: Green

You can also export to a file using the -o filename or --output filename flags:

flipt export -o flipt.yaml

By default, Flipt will export from the default namespace. Use the flag --namespace to export from a different namespace.

flipt export --namespace production

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Caching

Flipt supports both in-memory cache as well as Redis to enable faster reads and evaluations. Enabling caching has been shown to speed up read performance by several orders of magnitude.

Caching works as follows:

• All flag reads and evaluation requests go through the cache
• Flag cache entries are purged whenever a write to a flag or its variants occur or the TTL expires
• Evaluation cache entries are purged after the TTL expires only
• A cache miss will fetch the item from the database and add the item to the cache for the next read
• A cache hit will simply return the item from the cache, not interacting with the database

See the Cache section for how to configure caching.

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Expiration/Eviction

You can also configure an optional duration at which items in the cache are marked as expired.

For example, if you set the cache TTL to 5m, items that have been in the cache for longer than 5 minutes will be marked as expired, meaning the next read for that item will hit the database.

Setting an eviction interval (in-memory cache only) will automatically remove expired items from your cache at a defined period.

To tune the expiration and eviction interval of the cache set the following in your config:

cache:
  enabled: true
  backend: memory
  ttl: 5m # items older than 5 minutes will be marked as expired
  memory:
    eviction_interval: 2m # expired items will be evicted from the cache every 2 minutes