Reactors#

The reactors plugin runs live mutations. A live mutation is a stored mutation definition with live true and an optional integer priority. Enable it at open with plugins {reactors {}}. It has no settings. See plugin selection for the open options.

Store live mutations with patch_definition under the mutations kind. After each commit, every live mutation evaluates its query as of that transaction. Their patches commit together as one output transaction, completing a round. When patches write different values to one path, the higher priority wins. Equal priorities fail with Reactor_Conflict. The combined patch must satisfy the scoped schemas of every contributing live mutation. A schema rejection records Schema_Validation and commits no output. A failure keeps the cursor before its source transaction until a live mutation definition changes.

Runtime status#

Call status to inspect these fields:

When to call sync#

Live mutations run automatically after commits. Your write can finish before a live mutation has produced its output. Call sync before a read that depends on that output. For example, a live mutation can add greeted after a person is created. A read immediately after creation can miss greeted. Synchronize the reactors before asserting that result in a test. Applications that can observe the output later can let the runtime continue in the background.

Its options accept only the common maxWait option. Success covers source transactions committed before the call. Later transactions can still have pending rounds. A failed round reports failed and appears in status.

Operations#

Reactors::status#

pub fn status(&self) -> Result<Document>

Parameters#

Errors#

Notes#

The document describes the cursor, pending work, live mutations and failures: see runtime status.

Examples#

Describe the live mutation runtime#

let sync_options = stardust::parse("{maxWait {#dur PT5S}}", Format::DUST)?;
db.reactors().sync(Some(&sync_options))?;
let result = db.reactors().status()?;

C exports: stardust_db_plugin_call, stardust_result_take_document, stardust_result_error, stardust_result_release

Reactors::sync#

pub fn sync(&self, options: Option<&Document>) -> Result<()>

Parameters#

Errors#

Notes#

Database close interrupts an active wait. See when to call sync.

Examples#

Wait until live mutations caught up#

let sync_options = stardust::parse("{maxWait {#dur PT5S}}", Format::DUST)?;
db.reactors().sync(Some(&sync_options))?;
let result = db.reactors().status()?;

C exports: stardust_db_plugin_call, stardust_result_take_document, stardust_result_error, stardust_result_release