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use {
crate::{errors::*, objects::*},
anchor_lang::{prelude::*, system_program},
chrono::{DateTime, NaiveDateTime, Utc},
clockwork_cron::Schedule,
clockwork_pool_program::objects::Pool,
std::{
collections::hash_map::DefaultHasher,
hash::{Hash, Hasher},
mem::size_of,
str::FromStr,
},
};
/// Number of lamports to reimburse the worker with after they've submitted a transaction's worth of cranks.
const TRANSACTION_BASE_FEE_REIMBURSEMENT: u64 = 5000;
/// Accounts required by the `queue_crank` instruction.
#[derive(Accounts)]
#[instruction(data_hash: Option<u64>)]
pub struct QueueCrank<'info> {
/// The program config account.
#[account(address = Config::pubkey())]
pub config: Box<Account<'info, Config>>,
/// The worker's fee account.
#[account(
init_if_needed,
address = Fee::pubkey(worker.key()),
payer = worker,
space = 8 + size_of::<Fee>(),
)]
pub fee: Box<Account<'info, Fee>>,
/// The active worker pool.
#[account(address = config.worker_pool)]
pub pool: Box<Account<'info, Pool>>,
/// The queue to crank.
#[account(
mut,
address = queue.pubkey(),
constraint = !queue.paused @ ClockworkError::PausedQueue
)]
pub queue: Box<Account<'info, Queue>>,
/// The Solana system program.
#[account(address = system_program::ID)]
pub system_program: Program<'info, System>,
/// The worker.
#[account(mut)]
pub worker: Signer<'info>,
}
pub fn handler(ctx: Context<QueueCrank>, data_hash: Option<u64>) -> Result<()> {
// Get accounts
let config = &ctx.accounts.config;
let fee = &mut ctx.accounts.fee;
let pool = &ctx.accounts.pool;
let queue = &mut ctx.accounts.queue;
let worker = &ctx.accounts.worker;
// If this queue does not have a next_instruction, verify the queue's trigger has been met and a new exec_context can be created.
let current_slot = Clock::get().unwrap().slot;
if queue.next_instruction.is_none() {
match queue.trigger.clone() {
Trigger::Account { pubkey } => {
// Require the provided data hash is non-null.
let data_hash = match data_hash {
None => return Err(ClockworkError::InvalidQueueState.into()),
Some(data_hash) => data_hash,
};
// Verify proof that account data has been updated.
match ctx.remaining_accounts.first() {
None => {}
Some(account_info) => {
// Verify the remaining account is the account this queue is listening for.
require!(pubkey.eq(account_info.key), ClockworkError::InvalidTrigger);
// Begin computing the data hash of this account.
let mut hasher = DefaultHasher::new();
let data = &account_info.try_borrow_data().unwrap();
data.to_vec().hash(&mut hasher);
// Check the exec context for the prior data hash.
let expected_data_hash = match queue.exec_context.clone() {
None => {
// This queue has not begun executing yet.
// There is no prior data hash to include in our hash.
hasher.finish()
}
Some(exec_context) => {
match exec_context.trigger_context {
TriggerContext::Account {
data_hash: prior_data_hash,
} => {
// Inject the prior data hash as a seed.
prior_data_hash.hash(&mut hasher);
hasher.finish()
}
_ => return Err(ClockworkError::InvalidQueueState.into()),
}
}
};
// Verify the data hash provided by the worker is equal to the expected data hash.
// This proves the account has been updated since the last crank and the worker has seen the new data.
require!(
data_hash.eq(&expected_data_hash),
ClockworkError::InvalidTrigger
);
// Set a new exec context with the new data hash and slot number.
queue.exec_context = Some(ExecContext {
cranks_since_reimbursement: 0,
cranks_since_slot: 0,
last_crank_at: current_slot,
trigger_context: TriggerContext::Account { data_hash },
})
}
}
}
Trigger::Cron {
schedule,
skippable,
} => {
// Get the reference timestamp for calculating the queue's scheduled target timestamp.
let reference_timestamp = match queue.exec_context.clone() {
None => queue.created_at.unix_timestamp,
Some(exec_context) => match exec_context.trigger_context {
TriggerContext::Cron { started_at } => started_at,
_ => return Err(ClockworkError::InvalidQueueState.into()),
},
};
// Verify the current timestamp is greater than or equal to the threshold timestamp.
let current_timestamp = Clock::get().unwrap().unix_timestamp;
let threshold_timestamp = next_timestamp(reference_timestamp, schedule.clone())
.ok_or(ClockworkError::InvalidTrigger)?;
require!(
current_timestamp >= threshold_timestamp,
ClockworkError::InvalidTrigger
);
// If the schedule is marked as skippable, set the started_at of the exec context
// to be the threshold moment just before the current timestamp.
let started_at = if skippable && current_timestamp > threshold_timestamp {
prev_timestamp(current_timestamp, schedule)
.ok_or(ClockworkError::InvalidTrigger)?
} else {
threshold_timestamp
};
// Set the exec context.
queue.exec_context = Some(ExecContext {
cranks_since_reimbursement: 0,
cranks_since_slot: 0,
last_crank_at: current_slot,
trigger_context: TriggerContext::Cron { started_at },
});
}
Trigger::Immediate => {
// Set the exec context.
require!(
queue.exec_context.is_none(),
ClockworkError::InvalidQueueState
);
queue.exec_context = Some(ExecContext {
cranks_since_reimbursement: 0,
cranks_since_slot: 0,
last_crank_at: current_slot,
trigger_context: TriggerContext::Immediate,
});
}
}
}
// If the rate limit has been met, exit early.
match queue.exec_context {
None => return Err(ClockworkError::InvalidQueueState.into()),
Some(exec_context) => {
if exec_context.last_crank_at == Clock::get().unwrap().slot
&& exec_context.cranks_since_slot >= queue.rate_limit
{
return Err(ClockworkError::RateLimitExeceeded.into());
}
}
}
// Crank the queue
let bump = ctx.bumps.get("queue").unwrap();
queue.crank(ctx.remaining_accounts, *bump, worker)?;
// If worker is in the pool, pay automation fees.
let is_authorized_worker = pool.clone().into_inner().workers.contains(&worker.key());
if is_authorized_worker {
fee.escrow_balance(config.crank_fee, queue)?;
} else {
fee.escrow_withholding(config.crank_fee, queue)?;
}
// If the queue has no more work or the number of cranks since the last payout has reached the rate limit,
// reimburse the worker for the transaction base fee.
match queue.exec_context {
None => return Err(ClockworkError::InvalidQueueState.into()),
Some(exec_context) => {
if queue.next_instruction.is_none()
|| exec_context.cranks_since_reimbursement >= queue.rate_limit
{
fee.escrow_balance(TRANSACTION_BASE_FEE_REIMBURSEMENT, queue)?;
queue.exec_context = Some(ExecContext {
cranks_since_reimbursement: 0,
..exec_context
})
}
}
}
Ok(())
}
fn next_timestamp(after: i64, schedule: String) -> Option<i64> {
Schedule::from_str(&schedule)
.unwrap()
.next_after(&DateTime::<Utc>::from_utc(
NaiveDateTime::from_timestamp(after, 0),
Utc,
))
.take()
.map(|datetime| datetime.timestamp())
}
fn prev_timestamp(before: i64, schedule: String) -> Option<i64> {
Schedule::from_str(&schedule)
.unwrap()
.prev_before(&DateTime::<Utc>::from_utc(
NaiveDateTime::from_timestamp(before, 0),
Utc,
))
.take()
.map(|datetime| datetime.timestamp())
}