anchor

⚙️ Crank Counter

Simple counter program using Anchor and Ephemeral Rollups with scheduled cranks for automatic execution.

Software Packages

This program has utilized the following software packages.

Software	Version	Installation Guide
Solana	3.1.9	Install Solana
Rust	1.89.0	Install Rust
Anchor	1.0.2	Install Anchor
Node	24.10.0	Install Node

agave-install init 3.1.9
rustup install 1.89.0
avm use 1.0.2

Build and Test

Install dependencies and build the program:

yarn
yarn build

This example runs against a local MagicBlock cluster — a base Solana validator plus an Ephemeral Rollup, fronted by the Query Filtering Service. Start it in one terminal and leave it running:

yarn setup

yarn setup runs SETUP_ONLY=1 ./scripts/test-locally.sh crank-counter from the repo root: it builds this example, boots the validators, and holds them until you press a key.

Then, in a second terminal, run this example's tests against that cluster:

yarn test:local

test:local sources scripts/local-env.sh so the SDK targets the local cluster (without it the tests fall back to devnet).

Tip: to build and run every example end-to-end (what CI does), run the repo-root ./scripts/test-locally.sh directly.

⏱️ Scheduling a Crank

This example schedules an instruction to run automatically on the Ephemeral Rollup. After delegating the counter PDA, the program's schedule_increment instruction CPIs into the MagicBlock magic program with a ScheduleTask, which repeatedly invokes increment on a fixed interval for a number of iterations — no client transaction needed per tick.

pub fn schedule_increment(
    ctx: Context<ScheduleIncrement>,
    args: ScheduleIncrementArgs, // task_id, execution_interval_millis, iterations
) -> Result<()> {
    let increment_ix = Instruction {
        program_id: crate::ID,
        accounts: vec![AccountMeta::new(ctx.accounts.counter.key(), false)],
        data: anchor_lang::InstructionData::data(&crate::instruction::Increment {}),
    };

    let ix_data = bincode::serialize(&MagicBlockInstruction::ScheduleTask(ScheduleTaskArgs {
        task_id: args.task_id,
        execution_interval_millis: args.execution_interval_millis,
        iterations: args.iterations,
        instructions: vec![increment_ix],
    }))?;
    // ... CPI into MAGIC_PROGRAM_ID with the serialized ScheduleTask
}