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State

You can store key-value state in Restate. Restate makes sure the state is consistent with the processing of the code execution.

This feature is only available for Virtual Objects and Workflows:

  • For Virtual Objects, the state is isolated per Virtual Object and lives forever (across invocations for that object).
  • For Workflows, you can think of it as if every workflow execution is a new object. So the state is isolated to a single workflow execution. The state can only be mutated by the run handler of the workflow. The other handlers can only read the state.
Command-line introspection

You can inspect and edit the K/V state stored in Restate via psql and the CLI. Have a look at the introspection docs for more information.

Serializing state

You can store any type of value that can be serialized as a Buffer with Buffer.from(JSON.stringify(yourObject)) and deserialized with JSON.parse(result.toString()) as T.

Listing state keys

For a single Virtual Object, you can list all the state keys that have entries in the state store via:

const stateKeys = ctx.stateKeys();

Retrieving state

Use ctx.get to retrieve the state for a key:

const myString = (await ctx.get<string>("my-string-key")) ?? "my-default";

const myNumber = (await ctx.get<number>("my-number-key")) ?? 0;

The return value is null if no value was stored.

Setting state

Use ctx.set to set a new value for a key:

ctx.set("my-key", "my-new-value");

Clearing state

Use ctx.clear to delete the value of a key:

ctx.clear("my-key");

Clearing all state

Delete all the state stored in Restate for a Virtual Object via:

ctx.clearAll();