SQLite

This component allows using SQLite 3 as state store for Dapr.

The component is currently compiled with SQLite version 3.40.1.

Create a Dapr component

Create a file called sqlite.yaml, paste the following, and replace the <CONNECTION STRING> value with your connection string, which is the path to a file on disk.

If you want to also configure SQLite to store actors, add the actorStateStore option as in the example below.

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: <NAME>
spec:
  type: state.sqlite
  version: v1
  metadata:
  # Connection string
  - name: connectionString
    value: "data.db"
  # Timeout for database operations, in seconds (optional)
  #- name: timeoutInSeconds
  #  value: 20
  # Name of the table where to store the state (optional)
  #- name: tableName
  #  value: "state"
  # Cleanup interval in seconds, to remove expired rows (optional)
  #- name: cleanupIntervalInSeconds
  #  value: 3600
  # Uncomment this if you wish to use SQLite as a state store for actors (optional)
  #- name: actorStateStore
  #  value: "true"

Spec metadata fields

The connectionString parameter configures how to open the SQLite database.

• Normally, this is the path to a file on disk, relative to the current working directory, or absolute. For example: "data.db" (relative to the working directory) or "/mnt/data/mydata.db".
• The path is interpreted by the SQLite library, so it’s possible to pass additional options to the SQLite driver using “URI options” if the path begins with file:. For example: "file:path/to/data.db?mode=ro" opens the database at path path/to/data.db in read-only mode. Refer to the SQLite documentation for all supported URI options.
• The special case ":memory:" launches the component backed by an in-memory SQLite database. This database is not persisted on disk, not shared across multiple Dapr instances, and all data is lost when the Dapr sidecar is stopped. When using an in-memory database, you should always set the ?cache=shared URI option: "file::memory:?cache=shared"

Advanced

TTLs and cleanups

This state store supports Time-To-Live (TTL) for records stored with Dapr. When storing data using Dapr, you can set the ttlInSeconds metadata property to indicate when the data should be considered “expired”.

Because SQLite doesn’t have built-in support for TTLs, this is implemented in Dapr by adding a column in the state table indicating when the data is to be considered “expired”. Records that are “expired” are not returned to the caller, even if they’re still physically stored in the database. A background “garbage collector” periodically scans the state table for expired rows and deletes them.

The cleanupIntervalInSeconds metadata property sets the expired records deletion interval, which defaults to 3600 seconds (that is, 1 hour).

• Longer intervals require less frequent scans for expired rows, but can require storing expired records for longer, potentially requiring more storage space. If you plan to store many records in your state table, with short TTLs, consider setting cleanupIntervalInSeconds to a smaller value, for example 300 (300 seconds, or 5 minutes).
• If you do not plan to use TTLs with Dapr and the SQLite state store, you should consider setting cleanupIntervalInSeconds to a value <= 0 (e.g. 0 or -1) to disable the periodic cleanup and reduce the load on the database.

The expiration_time column in the state table, where the expiration date for records is stored, does not have an index by default, so each periodic cleanup must perform a full-table scan. If you have a table with a very large number of records, and only some of them use a TTL, you may find it useful to create an index on that column. Assuming that your state table name is state (the default), you can use this query:

CREATE INDEX idx_expiration_time
  ON state (expiration_time);

Related links

• Basic schema for a Dapr component
• Read this guide for instructions on configuring state store components
• State management building block