Tasks & Dependencies

Tasks are the fundamental unit of execution in ICE. A task is an atomic, asynchronous operation that can depend on other tasks.

Anatomy of a Task

Tasks are created using the task() builder pattern.

import { task } from "@ice.ts/runner";

export const mint = task("Mint tokens")
  // 1. Declare Dependencies
  .deps({ ledger: ledgerCanister })
  
  // 2. Execution Logic
  .run(async ({ ctx, deps }) => {
    const { ledger } = deps;
    console.log(`Minting on ledger: ${ledger.canisterId}`);
  })
  
  // 3. Finalize
  .make();

Dependencies vs. dependsOn

ICE distinguishes between functional dependencies and execution order.

• .deps(): Declares a dependency that you need to use inside your task. The return value of the dependency is injected into ctx.deps.
• .dependsOn(): Declares that a task must run before this one, but you don't need its return value.

Task Context (ctx)

The ctx object is passed to every task. It contains:

• ctx.users: The identities defined in your config.
• ctx.replica: The active connection to the IC or PocketIC.
• ctx.roles: Helper mapping for roles (e.g., ctx.roles.deployer).