ruststream-sqlx 0.7.1

//! The record of `examples/sqlx_outbox_statements.rs` described by hand: `OutboxSpec` names the
//! events the record writes itself with `.own::<..>()`, and the handlers are named types mounted
//! with `subscriber(..)`.
//!
//! ```text
//! RUSTSTREAM_SQLX_OUTBOX=on cargo run -p ruststream-sqlx --example manual_sqlx_outbox_statements --features outbox,sqlite,testing,asyncapi
//! ```

use std::error::Error;
use std::future::{Future, ready};

use ruststream::OutgoingMessage;
use ruststream::memory::prelude::*;
use ruststream::schemars::JsonSchema;
use ruststream_sqlx::outbox::{Outbox, TrackedName};
use serde::{Deserialize, Serialize};
use sqlx::SqlitePool;

// --8<-- [start:statements]
use ruststream_sqlx::dialect::Column;
use ruststream_sqlx::outbox::spec::{ProcessedAt, own};
use ruststream_sqlx::outbox::{self, OutboxSpec, OutboxTable};
use sqlx::{Sqlite, SqliteConnection};

/// One record of `order_outbox`, taken and released by statements of the service's own.
#[derive(sqlx::FromRow)]
struct OrderOutbox {
    id: i64,
    name: String,
    payload: Vec<u8>,
}

impl OutboxTable for OrderOutbox {
    type Id = i64;
    type Table = OutboxSpec<(ProcessedAt, own::Fetch, own::Retry)>;
    const TABLE: Self::Table = OutboxSpec::new(
        "order_outbox",
        Column::new("id"),
        Column::new("name"),
        Column::new("payload"),
    )
    .processed_at(Column::new("processed_at"))
    .own::<own::Fetch>()
    .own::<own::Retry>();

    fn id(&self) -> &i64 {
        &self.id
    }

    fn name(&self) -> &str {
        &self.name
    }

    fn payload(&self) -> &[u8] {
        &self.payload
    }
}

impl outbox::Publish<Sqlite> for OrderOutbox {
    async fn publish(conn: &mut SqliteConnection, msg: &OutgoingMessage<'_>) -> sqlx::Result<i64> {
        sqlx::query_scalar("INSERT INTO order_outbox (name, payload) VALUES (?, ?) RETURNING id")
            .bind(msg.name())
            .bind(msg.payload())
            .fetch_one(conn)
            .await
    }
}

/// Takes the record into work, or finds it taken or processed already (`None`).
impl outbox::Fetch<Sqlite> for OrderOutbox {
    async fn fetch(conn: &mut SqliteConnection, id: &i64) -> sqlx::Result<Option<Self>> {
        sqlx::query_as(
            "UPDATE order_outbox SET taken_at = CURRENT_TIMESTAMP
             WHERE id = ? AND taken_at IS NULL AND processed_at IS NULL
             RETURNING id, name, payload",
        )
        .bind(id)
        .fetch_optional(conn)
        .await
    }
}

/// Releases a record its consumer asked for again, and counts the attempt.
impl outbox::Retry<Sqlite> for OrderOutbox {
    async fn retry(conn: &mut SqliteConnection, id: &i64) -> sqlx::Result<()> {
        sqlx::query("UPDATE order_outbox SET taken_at = NULL, attempts = attempts + 1 WHERE id = ?")
            .bind(id)
            .execute(conn)
            .await
            .map(drop)
    }
}
// --8<-- [end:statements]

const SCHEMA: &str = "CREATE TABLE IF NOT EXISTS order_outbox (
    id INTEGER PRIMARY KEY,
    name TEXT NOT NULL,
    payload BLOB NOT NULL,
    taken_at TEXT,
    attempts INTEGER NOT NULL DEFAULT 0,
    processed_at TEXT
)";

#[derive(Debug, PartialEq, Deserialize, Serialize, JsonSchema)]
#[schemars(crate = "ruststream::schemars")]
struct PlaceOrder {
    id: u64,
    in_stock: bool,
}

impl OutgoingDestination for PlaceOrder {
    type Form = FixedName;
    const DESTINATION: &'static str = "checkout";
}

impl MessageHeaders for PlaceOrder {
    type Contract = NoHeaders;
}

#[derive(Debug, PartialEq, Deserialize, Serialize, JsonSchema)]
#[schemars(crate = "ruststream::schemars")]
struct OrderPlaced {
    id: u64,
    in_stock: bool,
}

impl OutgoingDestination for OrderPlaced {
    type Form = FixedName;
    const DESTINATION: &'static str = "orders";
}

impl MessageHeaders for OrderPlaced {
    type Contract = NoHeaders;
}

/// The name `OrderPlaced` is published under.
struct Orders;

impl TrackedName for Orders {
    const NAME: &'static str = "orders";
}

struct Place;

impl Handle<PlaceOrder, OrderPlaced> for Place {
    fn handle(
        &self,
        cmd: &PlaceOrder,
        _outs: &(),
        _ctx: &mut Context<'_>,
    ) -> impl Future<Output = Result<OrderPlaced, HandlerOutcome>> {
        ready(Ok(OrderPlaced {
            id: cmd.id,
            in_stock: cmd.in_stock,
        }))
    }
}

struct Fulfil;

impl Handle<OrderPlaced> for Fulfil {
    fn handle(
        &self,
        order: &OrderPlaced,
        _outs: &(),
        _ctx: &mut Context<'_>,
    ) -> impl Future<Output = Result<(), HandlerOutcome>> {
        if order.in_stock {
            tracing::info!(order = order.id, "fulfilling the order");
            ready(Ok(()))
        } else {
            ready(Err(HandlerOutcome::retry()))
        }
    }
}

fn service(pool: SqlitePool) -> impl App {
    let tracking = Outbox::new(pool).track::<OrderOutbox, Orders>();
    RustStream::new(AppInfo::new("orders", "0.1.0"))
        .layer(tracking.layer())
        .publish_layer(tracking.publish_layer())
        .with_broker(MemoryBroker::new(), |b| {
            b.include(subscriber("checkout", Place).reply().build())
                .out_reply(Publish);
            // One attempt: an order out of stock is not delivered again, and its record waits.
            b.include(subscriber("orders", Fulfil).build())
                .max_attempts(nonzero!(1u32));
            b.after_startup(Publish, tracking.republish());
        })
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    let pool = SqlitePool::connect("sqlite:orders.db?mode=rwc").await?;
    sqlx::raw_sql(SCHEMA).execute(&pool).await?;
    service(pool.clone()).run().await?;
    pool.close().await;
    Ok(())
}

#[cfg(test)]
mod tests {
    use std::env;
    use std::error::Error;

    use ruststream::memory::prelude::*;
    use ruststream::testing::TestApp;
    use sqlx::sqlite::{SqliteConnectOptions, SqlitePoolOptions};
    use sqlx::{Connection, SqliteConnection, SqlitePool};

    use super::{PlaceOrder, SCHEMA, service};

    // A test build tracks only with `RUSTSTREAM_SQLX_OUTBOX=on`, read once per process: without it
    // there is nothing to check, and a job that asked for every suite fails instead of passing.
    fn tracking_on() -> bool {
        if env::var("RUSTSTREAM_SQLX_OUTBOX").as_deref() == Ok("on") {
            return true;
        }
        assert!(
            env::var("RUSTSTREAM_REQUIRE_LIVE").map_or(true, |value| value.is_empty()),
            "RUSTSTREAM_REQUIRE_LIVE is set, but RUSTSTREAM_SQLX_OUTBOX is not `on`"
        );
        eprintln!("RUSTSTREAM_SQLX_OUTBOX is not `on`; skipping the outbox test");
        false
    }

    // An in-memory database every connection naming it shares, alive while one of them is open:
    // the test holds one beside the pool.
    async fn database(name: &str) -> Result<(SqlitePool, SqliteConnection), Box<dyn Error>> {
        let options: SqliteConnectOptions =
            format!("sqlite:file:{name}?mode=memory&cache=shared").parse()?;
        let keeper = SqliteConnection::connect_with(&options).await?;
        let pool = SqlitePoolOptions::new()
            .min_connections(1)
            .idle_timeout(None)
            .connect_with(options)
            .await?;
        sqlx::raw_sql(SCHEMA).execute(&pool).await?;
        Ok((pool, keeper))
    }

    #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
    async fn the_services_own_take_and_release_settle_the_records() -> Result<(), Box<dyn Error>> {
        if !tracking_on() {
            return Ok(());
        }
        let (pool, _keeper) = database("manual_sqlx_outbox_statements").await?;
        let tb = TestApp::start(service(pool.clone())).await?;
        let broker = tb.broker::<MemoryBroker>();
        broker
            .message(&PlaceOrder {
                id: 1,
                in_stock: true,
            })
            .publish()
            .await?;
        broker
            .message(&PlaceOrder {
                id: 2,
                in_stock: false,
            })
            .publish()
            .await?;

        // `(taken, attempts, processed)` of each record, in id order.
        let records: Vec<(bool, i64, bool)> = sqlx::query_as(
            "SELECT taken_at IS NOT NULL, attempts, processed_at IS NOT NULL
             FROM order_outbox ORDER BY id",
        )
        .fetch_all(&pool)
        .await?;
        assert_eq!(records, [(true, 0, true), (false, 1, false)]);
        Ok(())
    }
}