Embedded Rhai in a Postgres migration linter for custom lint rules

[ayarotsky]

I recently added Rhai as a scripting engine to diesel-guard, a Rust CLI linter for Postgres migrations.

The goal was to let teams enforce their own conventions and migration policies.

I shared my thoughts and integration guide in this write-up.

[schungx]

Wonderful work and a need that fits a scripting engine perfectly.

Some suggestions on idiomatic Rhai:

let stmt = node.IndexStmt;
if stmt == () { return; }

let name = stmt.idxname;
if name == "" { return; }

Can be more concisely written as:

let stmt = node.IndexStmt ?? return;
let name = stmt.idxname ?? return;

Or even:

let name = node.IndexStmt?.idxname;
if name?.starts_with("idx_") ?? true { return; }

#{
    operation: `Index naming violation: ${name}`,
    problem: `Index '${name}' does not follow naming convention. Names must start with 'idx_'.`,
    safe_alternative: `Rename: CREATE INDEX idx_${name} ON ...;`
}

Come to think of it, perhaps many of the builtin lints can also be converted into scripts such that they can be easily updated / tweaked.

[ayarotsky]

Thank you @schungx. This looks so much better. I'll update examples in the repo.

[schungx]

I use Rhai in a similar scenario, which is to do lints for data entry validation in a line of business app. Very convenient as client management always (I mean ALWAYS) change their minds and/or add new rules on the fly that MUST be active IMMEDIATELY. Go figure... LOL.

[ayarotsky]

I feel the pain 🤣