solana/src/accountant_stub.rs

//! The `accountant_stub` module is a client-side object that interfaces with a server-side Accountant
//! object via the network interface exposed by AccountantSkel. Client code should use
//! this object instead of writing messages to the network directly. The binary
//! encoding of its messages are unstable and may change in future releases.

use accountant_skel::{Request, Response, Subscription};
use bincode::{deserialize, serialize};
use futures::future::{ok, FutureResult};
use hash::Hash;
use signature::{KeyPair, PublicKey, Signature};
use std::collections::HashMap;
use std::io;
use std::net::{SocketAddr, UdpSocket};
use transaction::Transaction;

pub struct AccountantStub {
    pub addr: SocketAddr,
    pub socket: UdpSocket,
    last_id: Option<Hash>,
    num_events: u64,
    balances: HashMap<PublicKey, Option<i64>>,
}

impl AccountantStub {
    /// Create a new AccountantStub that will interface with AccountantSkel
    /// over `socket`. To receive responses, the caller must bind `socket`
    /// to a public address before invoking AccountantStub methods.
    pub fn new(addr: SocketAddr, socket: UdpSocket) -> Self {
        let stub = AccountantStub {
            addr: addr,
            socket,
            last_id: None,
            num_events: 0,
            balances: HashMap::new(),
        };
        stub.init();
        stub
    }

    pub fn init(&self) {
        let subscriptions = vec![Subscription::EntryInfo];
        let req = Request::Subscribe { subscriptions };
        let data = serialize(&req).expect("serialize Subscribe");
        trace!("subscribing to {}", self.addr);
        let _res = self.socket.send_to(&data, &self.addr);
    }

    pub fn recv_response(&self) -> io::Result<Response> {
        let mut buf = vec![0u8; 1024];
        self.socket.recv_from(&mut buf)?;
        let resp = deserialize(&buf).expect("deserialize balance");
        Ok(resp)
    }

    pub fn process_response(&mut self, resp: Response) {
        match resp {
            Response::Balance { key, val } => {
                self.balances.insert(key, val);
            }
            Response::EntryInfo(entry_info) => {
                self.last_id = Some(entry_info.id);
                self.num_events += entry_info.num_events;
            }
        }
    }

    /// Send a signed Transaction to the server for processing. This method
    /// does not wait for a response.
    pub fn transfer_signed(&self, tr: Transaction) -> io::Result<usize> {
        let req = Request::Transaction(tr);
        let data = serialize(&req).unwrap();
        self.socket.send_to(&data, &self.addr)
    }

    /// Creates, signs, and processes a Transaction. Useful for writing unit-tests.
    pub fn transfer(
        &self,
        n: i64,
        keypair: &KeyPair,
        to: PublicKey,
        last_id: &Hash,
    ) -> io::Result<Signature> {
        let tr = Transaction::new(keypair, to, n, *last_id);
        let sig = tr.sig;
        self.transfer_signed(tr).map(|_| sig)
    }

    /// Request the balance of the user holding `pubkey`. This method blocks
    /// until the server sends a response. If the response packet is dropped
    /// by the network, this method will hang indefinitely.
    pub fn get_balance(&mut self, pubkey: &PublicKey) -> FutureResult<i64, i64> {
        let req = Request::GetBalance { key: *pubkey };
        let data = serialize(&req).expect("serialize GetBalance");
        self.socket
            .send_to(&data, &self.addr)
            .expect("buffer error");
        let mut done = false;
        while !done {
            let resp = self.recv_response().expect("recv response");
            if let &Response::Balance { ref key, .. } = &resp {
                done = key == pubkey;
            }
            self.process_response(resp);
        }
        ok(self.balances[pubkey].unwrap())
    }

    /// Request the last Entry ID from the server. This method blocks
    /// until the server sends a response.
    pub fn get_last_id(&mut self) -> FutureResult<Hash, ()> {
        self.transaction_count();
        ok(self.last_id.unwrap_or(Hash::default()))
    }

    /// Return the number of transactions the server processed since creating
    /// this stub instance.
    pub fn transaction_count(&mut self) -> u64 {
        // Wait for at least one EntryInfo.
        let mut done = false;
        while !done {
            let resp = self.recv_response().expect("recv response");
            if let &Response::EntryInfo(_) = &resp {
                done = true;
            }
            self.process_response(resp);
        }

        // Then take the rest.
        self.socket.set_nonblocking(true).expect("set nonblocking");
        loop {
            match self.recv_response() {
                Err(_) => break,
                Ok(resp) => self.process_response(resp),
            }
        }
        self.socket.set_nonblocking(false).expect("set blocking");
        self.num_events
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use accountant::Accountant;
    use accountant_skel::AccountantSkel;
    use crdt::ReplicatedData;
    use futures::Future;
    use historian::Historian;
    use mint::Mint;
    use signature::{KeyPair, KeyPairUtil};
    use std::io::sink;
    use std::sync::atomic::{AtomicBool, Ordering};
    use std::sync::mpsc::sync_channel;
    use std::sync::Arc;
    use std::thread::sleep;
    use std::time::Duration;

    // TODO: Figure out why this test sometimes hangs on TravisCI.
    #[test]
    fn test_accountant_stub() {
        let gossip = UdpSocket::bind("0.0.0.0:0").unwrap();
        let serve = UdpSocket::bind("0.0.0.0:0").unwrap();
        let addr = serve.local_addr().unwrap();
        let pubkey = KeyPair::new().pubkey();
        let d = ReplicatedData::new(
            pubkey,
            gossip.local_addr().unwrap(),
            "0.0.0.0:0".parse().unwrap(),
            serve.local_addr().unwrap(),
        );

        let alice = Mint::new(10_000);
        let acc = Accountant::new(&alice);
        let bob_pubkey = KeyPair::new().pubkey();
        let exit = Arc::new(AtomicBool::new(false));
        let (input, event_receiver) = sync_channel(10);
        let historian = Historian::new(event_receiver, &alice.last_id(), Some(30));
        let acc = Arc::new(AccountantSkel::new(acc, input, historian));
        let threads = AccountantSkel::serve(&acc, d, serve, gossip, exit.clone(), sink()).unwrap();
        sleep(Duration::from_millis(300));

        let socket = UdpSocket::bind("0.0.0.0:0").unwrap();
        socket.set_read_timeout(Some(Duration::new(5, 0))).unwrap();

        let mut acc = AccountantStub::new(addr, socket);
        let last_id = acc.get_last_id().wait().unwrap();
        let _sig = acc.transfer(500, &alice.keypair(), bob_pubkey, &last_id)
            .unwrap();
        assert_eq!(acc.get_balance(&bob_pubkey).wait().unwrap(), 500);
        exit.store(true, Ordering::Relaxed);
        for t in threads {
            t.join().unwrap();
        }
    }
}