Struct DatabaseClock 

pub struct DatabaseClock;

The database’s own clock: #[inbox(clock = DatabaseClock)] makes the statements read it (statement_timestamp() on Postgres, UTC_TIMESTAMP(6) on MySQL) instead of binding the host’s time.

A table in the lease form reads the host’s clock: every settlement names the expiry its claim wrote, so the crate computes that expiry, and #[field(locked_until)] beside clock = DatabaseClock does not compile.

Examples

use std::time::Duration;

use chrono::{DateTime, Utc};
use ruststream_sqlx::prelude::*;
use ruststream_sqlx::DatabaseClock;
use serde::Deserialize;
use sqlx::PgPool;

/// Tasks written by hosts whose clocks drift: every claim and every delay reads one clock.
#[derive(Inbox, sqlx::FromRow)]
#[inbox(table = "sync_jobs", clock = DatabaseClock)]
pub struct SyncJob {
    #[field(id, generated)]
    id: i64,
    #[field(retry_after, generated)]
    retry_after: DateTime<Utc>,
    #[field(payload)]
    payload: Vec<u8>,
}

#[derive(Deserialize)]
struct Change {
    record: u64,
}

#[subscriber(InboxQueue::<SyncJob>::new("sync"))]
async fn sync(change: &Change) -> HandlerOutcome {
    if push(change).await {
        return HandlerOutcome::ack();
    }
    // Ten seconds by the database's clock, whichever host claimed the row.
    HandlerOutcome::retry_after(Duration::from_secs(10))
}

pub fn app(pool: PgPool) -> RustStream {
    RustStream::new(AppInfo::new("sync", "0.1.0")).with_broker(SqlxBroker::new(pool), |b| {
        b.include(sync);
    })
}

Trait Implementations

impl Clone for DatabaseClock

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for DatabaseClock

impl Debug for DatabaseClock

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for DatabaseClock

fn default() -> Self

Returns the “default value” for a type.

impl Eq for DatabaseClock

impl Hash for DatabaseClock

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for DatabaseClock

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for DatabaseClock

impl TimeSource for DatabaseClock

const DATABASE: bool = true

Whether the statements read the database’s own clock.

fn now() -> Option<SystemTime>

Now, for a statement that binds it; None where the database reads its own.