Advanced Solana Development Concepts

Clockwork threads

Clockwork threads are an automation primitive for developing Solana programs. Essentially, we can use Clockwork threads to execute a series of instructions on our programs on a schedule or in the event of some trigger.

You can trigger the execution of your smart contract using the following "triggers":

Trigger Condition	Description	Required Arguments
Account	Starts execution when an account's data changes.	`address`: Account address to monitor. `offset`: Byte offset of account data to monitor. `size`: Size of byte slice to monitor (must be less than 1kb).
Cron	Starts execution based on a cron schedule.	`schedule`: Schedule in cron syntax. `skippable`: Boolean indicating if invocation can be skipped during Solana network unavailability.
Now	Starts execution immediately.	None
Slot	Starts execution when a specified slot passes.	`slot`: The slot to begin execution on.
Epoch	Starts execution when a specified epoch becomes active.	`epoch`: The epoch to begin execution on.
Timestamp	Starts execution when a specified Unix timestamp has passed.	`unix_ts`: The Unix timestamp to begin execution on.
Pyth	Starts execution when a price threshold is crossed.	`price_feed`: The Pyth price feed account to monitor. `equality`: Equality operator (≥ or ≤) to compare the price feed with the limit price. `limit`: Limit price that triggers execution.

Creating automated cron jobs for the execution of your Solana programs opens up a world of new use cases, such as:

Recurring payments: Executes an SPL token transfer on a user-defined schedule
Token distribution: Mints a new token and sends it to a target user every 60 seconds
Subscriptions: Allows users to pay on a recurrent schedule

Below, I will walk you through what it looks like to create a Clockwork thread via cross program invocation (CPI) using the Anchor framework:

  let bump = *ctx.bumps.get("thread_authority").unwrap();
  clockwork_sdk::cpi::thread_create(
      CpiContext::new_with_signer(
          clockwork_program.to_account_info(),
          clockwork_sdk::cpi::ThreadCreate {
              payer: payer.to_account_info(),
              system_program: system_program.to_account_info(),
              thread: thread.to_account_info(),
              authority: thread_authority.to_account_info(),
          },
          &[&[THREAD_AUTHORITY_SEED,payer.key().as_ref() , &[bump]]],
      ),
      LAMPORTS_PER_SOL / 10, // amount (0.1 sol)
      thread_id,              // id
      vec![target_ix.into()], // instructions
      trigger,                // trigger
  )?;