Tokio-Postgres Macros

Proc-macros for working with tokio-postgres:

• from_row_derive — #[derive(FromRow, ToRow)] for mapping between Postgres rows and Rust structs. ToRow generates a batch_insert(&[T], &client) helper that issues one INSERT … SELECT * FROM UNNEST(…) per batch.
• from_row — runtime companion to the derive. Re-exports the derives plus the query_as! / query! / query_scalar! macros.
• query_as — proc-macro that parses the SQL at compile time, checks it against a live database (via DATABASE_URL), and emits a typed, bound call to client.query(...).
• query_as_core — non-proc-macro shim that hosts the shared tokio runtime + Postgres client used by the proc-macro crates. (Proc-macro crates can only export proc-macros, so runtime infrastructure has to live in a separate non-proc-macro crate.)

Usage

Add to Cargo.toml:

[dependencies]
from_row = { git = "https://github.com/YOUR_HANDLE/pg-macros" }

Then:

use from_row::{FromRow, ToRow, query_as, UuidBind};
use uuid::Uuid;

#[derive(FromRow, ToRow)]
struct User {
    id: Uuid,
    email: String,
}

let rows: Vec<User> = query_as!(
    User,
    "SELECT id, email FROM users WHERE organization_id = $1",
    org_id,
).fetch_all(&client).await?;

Compile-time SQL checks

query_as! parses the SQL and, if DATABASE_URL is set at compile time, validates the query against the live schema. Without DATABASE_URL it skips validation and emits a runtime-bound query.

export DATABASE_URL="host=localhost user=erp password=erp dbname=erp_dev"
cargo build

UuidBind

query_as! accepts any type that implements UuidBind as a UUID parameter. uuid::Uuid is implemented by default. Newtype wrappers can opt in with a one-liner:

#[derive(Clone, Copy, PartialEq, Eq, Hash)]
pub struct UserId(uuid::Uuid);
impl from_row::UuidBind for UserId {}

Or use a companion Id derive macro that emits impl UuidBind alongside other id-trait impls.

History

Extracted from an in-tree macros/ directory of a larger application that migrated off Postgres. Kept here for projects that still need compile-time-checked SQL.

License

MIT OR Apache-2.0.