Consume another context's services with `consumes`

Goal: call a service that belongs to another context.

A context declares the contexts it depends on with consumes, then calls their services. Suppose a payment context offers an authorise service:

context payment

service authorise {
  on call(amount: Int) -> Effect[Result[Int, Int]] {
    Ok(amount)
  }
}

Declare the dependency and call the service

In the consuming context, declare consumes <context> and call the service by its qualified name. Service calls are effectful, so bind the result with <-:

context orders

consumes payment

service placeOrder {
  on call(total: Int) -> Effect[Result[Int, Int]] {
    let _ <- payment.authorise(total)
    Ok(total)
  }
}

Use an alias

Add as <Alias> to call through a shorter name:

context orders

consumes payment as Pay

service placeOrder {
  on call(total: Int) -> Effect[Result[Int, Int]] {
    let _ <- Pay.authorise(total)
    Ok(total)
  }
}

How it compiles

The call is the same Bynk code on both targets, but the emitted wiring differs:

• bundle (default) — a direct in-process function call through a composed surface.
• workers — a JSON call over a Cloudflare Service Binding, with the arguments and result validated as they cross the boundary.

See Target Cloudflare Workers for the target details.

Related

• Reference: type system.
• Explanation: How a Bynk program is shaped.