Add solana-client crate

client/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "solana-client"
+version = "0.13.0"
+description = "Solana Client"
+authors = ["Solana Maintainers <maintainers@solana.com>"]
+repository = "https://github.com/solana-labs/solana"
+homepage = "https://solana.com/"
+license = "Apache-2.0"
+edition = "2018"
+
+[dependencies]
+bincode = "1.1.2"
+bs58 = "0.2.0"
+log = "0.4.2"
+reqwest = "0.9.11"
+serde_json = "1.0.39"
+solana-metrics = { path = "../metrics", version = "0.13.0" }
+solana-sdk = { path = "../sdk", version = "0.13.0" }
+
+[dev-dependencies]
+jsonrpc-core = "10.1.0"
+jsonrpc-http-server = "10.1.0"
+solana-logger = { path = "../logger", version = "0.13.0" }

client/src/lib.rs

@@ -0,0 +1,3 @@
+pub mod rpc_mock;
+pub mod rpc_request;
+pub mod thin_client;

client/src/rpc_mock.rs

@@ -0,0 +1,111 @@
+// Implementation of RpcRequestHandler trait for testing Rpc requests without i/o
+
+use crate::rpc_request::{RpcRequest, RpcRequestHandler};
+use serde_json::{json, Number, Value};
+use solana_sdk::hash::Hash;
+use solana_sdk::pubkey::Pubkey;
+use solana_sdk::signature::{Keypair, KeypairUtil};
+use solana_sdk::system_transaction::SystemTransaction;
+use solana_sdk::transaction::Transaction;
+use std::error;
+use std::io::{Error, ErrorKind};
+use std::net::SocketAddr;
+
+pub const PUBKEY: &str = "7RoSF9fUmdphVCpabEoefH81WwrW7orsWonXWqTXkKV8";
+pub const SIGNATURE: &str =
+    "43yNSFC6fYTuPgTNFFhF4axw7AfWxB2BPdurme8yrsWEYwm8299xh8n6TAHjGymiSub1XtyxTNyd9GBfY2hxoBw8";
+
+#[derive(Clone)]
+pub struct MockRpcClient {
+    pub addr: String,
+}
+
+impl MockRpcClient {
+    pub fn new(addr: String) -> Self {
+        MockRpcClient { addr }
+    }
+
+    pub fn retry_get_balance(
+        &self,
+        id: u64,
+        pubkey: &Pubkey,
+        retries: usize,
+    ) -> Result<Option<u64>, Box<dyn error::Error>> {
+        let params = json!([format!("{}", pubkey)]);
+        let res = self
+            .retry_make_rpc_request(id, &RpcRequest::GetBalance, Some(params), retries)?
+            .as_u64();
+        Ok(res)
+    }
+
+    pub fn retry_make_rpc_request(
+        &self,
+        _id: u64,
+        request: &RpcRequest,
+        params: Option<Value>,
+        mut _retries: usize,
+    ) -> Result<Value, Box<dyn error::Error>> {
+        if self.addr == "fails" {
+            return Ok(Value::Null);
+        }
+        let val = match request {
+            RpcRequest::ConfirmTransaction => {
+                if let Some(Value::Array(param_array)) = params {
+                    if let Value::String(param_string) = &param_array[0] {
+                        Value::Bool(param_string == SIGNATURE)
+                    } else {
+                        Value::Null
+                    }
+                } else {
+                    Value::Null
+                }
+            }
+            RpcRequest::GetBalance => {
+                let n = if self.addr == "airdrop" { 0 } else { 50 };
+                Value::Number(Number::from(n))
+            }
+            RpcRequest::GetRecentBlockhash => Value::String(PUBKEY.to_string()),
+            RpcRequest::GetSignatureStatus => {
+                let str = if self.addr == "account_in_use" {
+                    "AccountInUse"
+                } else if self.addr == "bad_sig_status" {
+                    "Nonexistent"
+                } else {
+                    "Confirmed"
+                };
+                Value::String(str.to_string())
+            }
+            RpcRequest::GetTransactionCount => Value::Number(Number::from(1234)),
+            RpcRequest::SendTransaction => Value::String(SIGNATURE.to_string()),
+            _ => Value::Null,
+        };
+        Ok(val)
+    }
+}
+
+impl RpcRequestHandler for MockRpcClient {
+    fn make_rpc_request(
+        &self,
+        id: u64,
+        request: RpcRequest,
+        params: Option<Value>,
+    ) -> Result<Value, Box<dyn error::Error>> {
+        self.retry_make_rpc_request(id, &request, params, 0)
+    }
+}
+
+pub fn request_airdrop_transaction(
+    _drone_addr: &SocketAddr,
+    _id: &Pubkey,
+    lamports: u64,
+    _blockhash: Hash,
+) -> Result<Transaction, Error> {
+    if lamports == 0 {
+        Err(Error::new(ErrorKind::Other, "Airdrop failed"))?
+    }
+    let key = Keypair::new();
+    let to = Keypair::new().pubkey();
+    let blockhash = Hash::default();
+    let tx = SystemTransaction::new_account(&key, &to, lamports, blockhash, 0);
+    Ok(tx)
+}

client/src/rpc_request.rs

@@ -0,0 +1,331 @@
+use log::*;
+use reqwest;
+use reqwest::header::CONTENT_TYPE;
+use serde_json::{json, Value};
+use solana_sdk::timing::{DEFAULT_TICKS_PER_SLOT, NUM_TICKS_PER_SECOND};
+use std::net::SocketAddr;
+use std::thread::sleep;
+use std::time::Duration;
+use std::{error, fmt};
+
+use solana_sdk::pubkey::Pubkey;
+
+#[derive(Clone)]
+pub struct RpcClient {
+    pub client: reqwest::Client,
+    pub addr: String,
+}
+
+impl RpcClient {
+    pub fn new(addr: String) -> Self {
+        RpcClient {
+            client: reqwest::Client::new(),
+            addr,
+        }
+    }
+
+    pub fn new_with_timeout(addr: SocketAddr, timeout: Duration) -> Self {
+        let addr = get_rpc_request_str(addr, false);
+        let client = reqwest::Client::builder()
+            .timeout(timeout)
+            .build()
+            .expect("build rpc client");
+        RpcClient { client, addr }
+    }
+
+    pub fn new_from_socket(addr: SocketAddr) -> Self {
+        Self::new(get_rpc_request_str(addr, false))
+    }
+
+    pub fn retry_get_balance(
+        &self,
+        id: u64,
+        pubkey: &Pubkey,
+        retries: usize,
+    ) -> Result<Option<u64>, Box<dyn error::Error>> {
+        let params = json!([format!("{}", pubkey)]);
+        let res = self
+            .retry_make_rpc_request(id, &RpcRequest::GetBalance, Some(params), retries)?
+            .as_u64();
+        Ok(res)
+    }
+
+    pub fn retry_make_rpc_request(
+        &self,
+        id: u64,
+        request: &RpcRequest,
+        params: Option<Value>,
+        mut retries: usize,
+    ) -> Result<Value, Box<dyn error::Error>> {
+        let request_json = request.build_request_json(id, params);
+
+        loop {
+            match self
+                .client
+                .post(&self.addr)
+                .header(CONTENT_TYPE, "application/json")
+                .body(request_json.to_string())
+                .send()
+            {
+                Ok(mut response) => {
+                    let json: Value = serde_json::from_str(&response.text()?)?;
+                    if json["error"].is_object() {
+                        Err(RpcError::RpcRequestError(format!(
+                            "RPC Error response: {}",
+                            serde_json::to_string(&json["error"]).unwrap()
+                        )))?
+                    }
+                    return Ok(json["result"].clone());
+                }
+                Err(e) => {
+                    info!(
+                        "make_rpc_request() failed, {} retries left: {:?}",
+                        retries, e
+                    );
+                    if retries == 0 {
+                        Err(e)?;
+                    }
+                    retries -= 1;
+
+                    // Sleep for approximately half a slot
+                    sleep(Duration::from_millis(
+                        500 * DEFAULT_TICKS_PER_SLOT / NUM_TICKS_PER_SECOND,
+                    ));
+                }
+            }
+        }
+    }
+}
+
+pub fn get_rpc_request_str(rpc_addr: SocketAddr, tls: bool) -> String {
+    if tls {
+        format!("https://{}", rpc_addr)
+    } else {
+        format!("http://{}", rpc_addr)
+    }
+}
+
+pub trait RpcRequestHandler {
+    fn make_rpc_request(
+        &self,
+        id: u64,
+        request: RpcRequest,
+        params: Option<Value>,
+    ) -> Result<Value, Box<dyn error::Error>>;
+}
+
+impl RpcRequestHandler for RpcClient {
+    fn make_rpc_request(
+        &self,
+        id: u64,
+        request: RpcRequest,
+        params: Option<Value>,
+    ) -> Result<Value, Box<dyn error::Error>> {
+        self.retry_make_rpc_request(id, &request, params, 0)
+    }
+}
+
+#[derive(Debug, PartialEq)]
+pub enum RpcRequest {
+    ConfirmTransaction,
+    GetAccountInfo,
+    GetBalance,
+    GetRecentBlockhash,
+    GetSignatureStatus,
+    GetTransactionCount,
+    RequestAirdrop,
+    SendTransaction,
+    RegisterNode,
+    SignVote,
+    DeregisterNode,
+    GetStorageBlockhash,
+    GetStorageEntryHeight,
+    GetStoragePubkeysForEntryHeight,
+    FullnodeExit,
+}
+
+impl RpcRequest {
+    fn build_request_json(&self, id: u64, params: Option<Value>) -> Value {
+        let jsonrpc = "2.0";
+        let method = match self {
+            RpcRequest::ConfirmTransaction => "confirmTransaction",
+            RpcRequest::GetAccountInfo => "getAccountInfo",
+            RpcRequest::GetBalance => "getBalance",
+            RpcRequest::GetRecentBlockhash => "getRecentBlockhash",
+            RpcRequest::GetSignatureStatus => "getSignatureStatus",
+            RpcRequest::GetTransactionCount => "getTransactionCount",
+            RpcRequest::RequestAirdrop => "requestAirdrop",
+            RpcRequest::SendTransaction => "sendTransaction",
+            RpcRequest::RegisterNode => "registerNode",
+            RpcRequest::SignVote => "signVote",
+            RpcRequest::DeregisterNode => "deregisterNode",
+            RpcRequest::GetStorageBlockhash => "getStorageBlockhash",
+            RpcRequest::GetStorageEntryHeight => "getStorageEntryHeight",
+            RpcRequest::GetStoragePubkeysForEntryHeight => "getStoragePubkeysForEntryHeight",
+            RpcRequest::FullnodeExit => "fullnodeExit",
+        };
+        let mut request = json!({
+           "jsonrpc": jsonrpc,
+           "id": id,
+           "method": method,
+        });
+        if let Some(param_string) = params {
+            request["params"] = param_string;
+        }
+        request
+    }
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum RpcError {
+    RpcRequestError(String),
+}
+
+impl fmt::Display for RpcError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "invalid")
+    }
+}
+
+impl error::Error for RpcError {
+    fn description(&self) -> &str {
+        "invalid"
+    }
+
+    fn cause(&self) -> Option<&dyn error::Error> {
+        // Generic error, underlying cause isn't tracked.
+        None
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use jsonrpc_core::{Error, IoHandler, Params};
+    use jsonrpc_http_server::{AccessControlAllowOrigin, DomainsValidation, ServerBuilder};
+    use serde_json::Number;
+    use solana_logger;
+    use std::sync::mpsc::channel;
+    use std::thread;
+
+    #[test]
+    fn test_build_request_json() {
+        let test_request = RpcRequest::GetAccountInfo;
+        let addr = json!(["deadbeefXjn8o3yroDHxUtKsZZgoy4GPkPPXfouKNHhx"]);
+        let request = test_request.build_request_json(1, Some(addr.clone()));
+        assert_eq!(request["method"], "getAccountInfo");
+        assert_eq!(request["params"], addr,);
+
+        let test_request = RpcRequest::GetBalance;
+        let request = test_request.build_request_json(1, Some(addr));
+        assert_eq!(request["method"], "getBalance");
+
+        let test_request = RpcRequest::GetRecentBlockhash;
+        let request = test_request.build_request_json(1, None);
+        assert_eq!(request["method"], "getRecentBlockhash");
+
+        let test_request = RpcRequest::GetTransactionCount;
+        let request = test_request.build_request_json(1, None);
+        assert_eq!(request["method"], "getTransactionCount");
+
+        let test_request = RpcRequest::RequestAirdrop;
+        let request = test_request.build_request_json(1, None);
+        assert_eq!(request["method"], "requestAirdrop");
+
+        let test_request = RpcRequest::SendTransaction;
+        let request = test_request.build_request_json(1, None);
+        assert_eq!(request["method"], "sendTransaction");
+    }
+    #[test]
+    fn test_make_rpc_request() {
+        let (sender, receiver) = channel();
+        thread::spawn(move || {
+            let rpc_addr = "0.0.0.0:0".parse().unwrap();
+            let mut io = IoHandler::default();
+            // Successful request
+            io.add_method("getBalance", |_params: Params| {
+                Ok(Value::Number(Number::from(50)))
+            });
+            // Failed request
+            io.add_method("getRecentBlockhash", |params: Params| {
+                if params != Params::None {
+                    Err(Error::invalid_request())
+                } else {
+                    Ok(Value::String(
+                        "deadbeefXjn8o3yroDHxUtKsZZgoy4GPkPPXfouKNHhx".to_string(),
+                    ))
+                }
+            });
+
+            let server = ServerBuilder::new(io)
+                .threads(1)
+                .cors(DomainsValidation::AllowOnly(vec![
+                    AccessControlAllowOrigin::Any,
+                ]))
+                .start_http(&rpc_addr)
+                .expect("Unable to start RPC server");
+            sender.send(*server.address()).unwrap();
+            server.wait();
+        });
+
+        let rpc_addr = receiver.recv().unwrap();
+        let rpc_client = RpcClient::new_from_socket(rpc_addr);
+
+        let balance = rpc_client.make_rpc_request(
+            1,
+            RpcRequest::GetBalance,
+            Some(json!(["deadbeefXjn8o3yroDHxUtKsZZgoy4GPkPPXfouKNHhx"])),
+        );
+        assert_eq!(balance.unwrap().as_u64().unwrap(), 50);
+
+        let blockhash = rpc_client.make_rpc_request(2, RpcRequest::GetRecentBlockhash, None);
+        assert_eq!(
+            blockhash.unwrap().as_str().unwrap(),
+            "deadbeefXjn8o3yroDHxUtKsZZgoy4GPkPPXfouKNHhx"
+        );
+
+        // Send erroneous parameter
+        let blockhash =
+            rpc_client.make_rpc_request(3, RpcRequest::GetRecentBlockhash, Some(json!("paramter")));
+        assert_eq!(blockhash.is_err(), true);
+    }
+
+    #[test]
+    fn test_retry_make_rpc_request() {
+        solana_logger::setup();
+        let (sender, receiver) = channel();
+        thread::spawn(move || {
+            // 1. Pick a random port
+            // 2. Tell the client to start using it
+            // 3. Delay for 1.5 seconds before starting the server to ensure the client will fail
+            //    and need to retry
+            let rpc_addr: SocketAddr = "0.0.0.0:4242".parse().unwrap();
+            sender.send(rpc_addr.clone()).unwrap();
+            sleep(Duration::from_millis(1500));
+
+            let mut io = IoHandler::default();
+            io.add_method("getBalance", move |_params: Params| {
+                Ok(Value::Number(Number::from(5)))
+            });
+            let server = ServerBuilder::new(io)
+                .threads(1)
+                .cors(DomainsValidation::AllowOnly(vec![
+                    AccessControlAllowOrigin::Any,
+                ]))
+                .start_http(&rpc_addr)
+                .expect("Unable to start RPC server");
+            server.wait();
+        });
+
+        let rpc_addr = receiver.recv().unwrap();
+        let rpc_client = RpcClient::new_from_socket(rpc_addr);
+
+        let balance = rpc_client.retry_make_rpc_request(
+            1,
+            &RpcRequest::GetBalance,
+            Some(json!(["deadbeefXjn8o3yroDHxUtKsZZgoy4GPkPPXfouKNHhw"])),
+            10,
+        );
+        assert_eq!(balance.unwrap().as_u64().unwrap(), 5);
+    }
+}

client/src/thin_client.rs

@@ -0,0 +1,411 @@
+//! The `thin_client` module is a client-side object that interfaces with
+//! a server-side TPU.  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 crate::rpc_request::{RpcClient, RpcRequest, RpcRequestHandler};
+use bincode::serialize_into;
+use bs58;
+use log::*;
+use serde_json::json;
+use solana_metrics;
+use solana_metrics::influxdb;
+use solana_sdk::account::Account;
+use solana_sdk::hash::Hash;
+use solana_sdk::packet::PACKET_DATA_SIZE;
+use solana_sdk::pubkey::Pubkey;
+use solana_sdk::signature::{Keypair, KeypairUtil, Signature};
+use solana_sdk::system_transaction::SystemTransaction;
+use solana_sdk::timing;
+use solana_sdk::transaction::Transaction;
+use std;
+use std::io;
+use std::net::{SocketAddr, UdpSocket};
+use std::thread::sleep;
+use std::time::Duration;
+use std::time::Instant;
+
+/// An object for querying and sending transactions to the network.
+pub struct ThinClient {
+    rpc_addr: SocketAddr,
+    transactions_addr: SocketAddr,
+    transactions_socket: UdpSocket,
+    rpc_client: RpcClient,
+}
+
+impl ThinClient {
+    /// Create a new ThinClient that will interface with the Rpc at `rpc_addr` using TCP
+    /// and the Tpu at `transactions_addr` over `transactions_socket` using UDP.
+    pub fn new(
+        rpc_addr: SocketAddr,
+        transactions_addr: SocketAddr,
+        transactions_socket: UdpSocket,
+    ) -> Self {
+        Self::new_from_client(
+            rpc_addr,
+            transactions_addr,
+            transactions_socket,
+            RpcClient::new_from_socket(rpc_addr),
+        )
+    }
+
+    pub fn new_with_timeout(
+        rpc_addr: SocketAddr,
+        transactions_addr: SocketAddr,
+        transactions_socket: UdpSocket,
+        timeout: Duration,
+    ) -> Self {
+        let rpc_client = RpcClient::new_with_timeout(rpc_addr, timeout);
+        Self::new_from_client(rpc_addr, transactions_addr, transactions_socket, rpc_client)
+    }
+
+    fn new_from_client(
+        rpc_addr: SocketAddr,
+        transactions_addr: SocketAddr,
+        transactions_socket: UdpSocket,
+        rpc_client: RpcClient,
+    ) -> Self {
+        ThinClient {
+            rpc_client,
+            rpc_addr,
+            transactions_addr,
+            transactions_socket,
+        }
+    }
+
+    /// Send a signed Transaction to the server for processing. This method
+    /// does not wait for a response.
+    pub fn transfer_signed(&self, transaction: &Transaction) -> io::Result<Signature> {
+        let mut buf = vec![0; transaction.serialized_size().unwrap() as usize];
+        let mut wr = std::io::Cursor::new(&mut buf[..]);
+        serialize_into(&mut wr, &transaction)
+            .expect("serialize Transaction in pub fn transfer_signed");
+        assert!(buf.len() < PACKET_DATA_SIZE);
+        self.transactions_socket
+            .send_to(&buf[..], &self.transactions_addr)?;
+        Ok(transaction.signatures[0])
+    }
+
+    /// Retry a sending a signed Transaction to the server for processing.
+    pub fn retry_transfer(
+        &mut self,
+        keypair: &Keypair,
+        transaction: &mut Transaction,
+        tries: usize,
+    ) -> io::Result<Signature> {
+        for x in 0..tries {
+            transaction.sign(&[keypair], self.get_recent_blockhash());
+            let mut buf = vec![0; transaction.serialized_size().unwrap() as usize];
+            let mut wr = std::io::Cursor::new(&mut buf[..]);
+            serialize_into(&mut wr, &transaction)
+                .expect("serialize Transaction in pub fn transfer_signed");
+            self.transactions_socket
+                .send_to(&buf[..], &self.transactions_addr)?;
+            if self.poll_for_signature(&transaction.signatures[0]).is_ok() {
+                return Ok(transaction.signatures[0]);
+            }
+            info!("{} tries failed transfer to {}", x, self.transactions_addr);
+        }
+        Err(io::Error::new(
+            io::ErrorKind::Other,
+            "retry_transfer failed",
+        ))
+    }
+
+    /// Creates, signs, and processes a Transaction. Useful for writing unit-tests.
+    pub fn transfer(
+        &self,
+        lamports: u64,
+        keypair: &Keypair,
+        to: &Pubkey,
+        blockhash: &Hash,
+    ) -> io::Result<Signature> {
+        debug!(
+            "transfer: lamports={} from={:?} to={:?} blockhash={:?}",
+            lamports,
+            keypair.pubkey(),
+            to,
+            blockhash
+        );
+        let now = Instant::now();
+        let transaction = SystemTransaction::new_account(keypair, to, lamports, *blockhash, 0);
+        let result = self.transfer_signed(&transaction);
+        solana_metrics::submit(
+            influxdb::Point::new("thinclient")
+                .add_tag("op", influxdb::Value::String("transfer".to_string()))
+                .add_field(
+                    "duration_ms",
+                    influxdb::Value::Integer(timing::duration_as_ms(&now.elapsed()) as i64),
+                )
+                .to_owned(),
+        );
+        result
+    }
+
+    pub fn get_account_userdata(&mut self, pubkey: &Pubkey) -> io::Result<Option<Vec<u8>>> {
+        let params = json!([format!("{}", pubkey)]);
+        let response =
+            self.rpc_client
+                .make_rpc_request(1, RpcRequest::GetAccountInfo, Some(params));
+        match response {
+            Ok(account_json) => {
+                let account: Account =
+                    serde_json::from_value(account_json).expect("deserialize account");
+                Ok(Some(account.userdata))
+            }
+            Err(error) => {
+                debug!("get_account_userdata failed: {:?}", error);
+                Err(io::Error::new(
+                    io::ErrorKind::Other,
+                    "get_account_userdata failed",
+                ))
+            }
+        }
+    }
+
+    /// 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: &Pubkey) -> io::Result<u64> {
+        trace!("get_balance sending request to {}", self.rpc_addr);
+        let params = json!([format!("{}", pubkey)]);
+        let response =
+            self.rpc_client
+                .make_rpc_request(1, RpcRequest::GetAccountInfo, Some(params));
+
+        response
+            .and_then(|account_json| {
+                let account: Account =
+                    serde_json::from_value(account_json).expect("deserialize account");
+                trace!("Response account {:?} {:?}", pubkey, account);
+                trace!("get_balance {:?}", account.lamports);
+                Ok(account.lamports)
+            })
+            .map_err(|error| {
+                debug!("Response account {}: None (error: {:?})", pubkey, error);
+                io::Error::new(io::ErrorKind::Other, "AccountNotFound")
+            })
+    }
+
+    /// Request the transaction count.  If the response packet is dropped by the network,
+    /// this method will try again 5 times.
+    pub fn transaction_count(&mut self) -> u64 {
+        debug!("transaction_count");
+        for _tries in 0..5 {
+            let response =
+                self.rpc_client
+                    .make_rpc_request(1, RpcRequest::GetTransactionCount, None);
+
+            match response {
+                Ok(value) => {
+                    debug!("transaction_count response: {:?}", value);
+                    let transaction_count = value.as_u64().unwrap();
+                    return transaction_count;
+                }
+                Err(error) => {
+                    debug!("transaction_count failed: {:?}", error);
+                }
+            };
+        }
+        0
+    }
+
+    /// Request the last Entry ID from the server without blocking.
+    /// Returns the blockhash Hash or None if there was no response from the server.
+    pub fn try_get_recent_blockhash(&mut self, mut num_retries: u64) -> Option<Hash> {
+        loop {
+            trace!("try_get_recent_blockhash send_to {}", &self.rpc_addr);
+            let response =
+                self.rpc_client
+                    .make_rpc_request(1, RpcRequest::GetRecentBlockhash, None);
+
+            match response {
+                Ok(value) => {
+                    let blockhash_str = value.as_str().unwrap();
+                    let blockhash_vec = bs58::decode(blockhash_str).into_vec().unwrap();
+                    return Some(Hash::new(&blockhash_vec));
+                }
+                Err(error) => {
+                    debug!("thin_client get_recent_blockhash error: {:?}", error);
+                    num_retries -= 1;
+                    if num_retries == 0 {
+                        return None;
+                    }
+                }
+            }
+        }
+    }
+
+    /// Request the last Entry ID from the server. This method blocks
+    /// until the server sends a response.
+    pub fn get_recent_blockhash(&mut self) -> Hash {
+        loop {
+            trace!("get_recent_blockhash send_to {}", &self.rpc_addr);
+            if let Some(hash) = self.try_get_recent_blockhash(10) {
+                return hash;
+            }
+        }
+    }
+
+    /// Request a new last Entry ID from the server. This method blocks
+    /// until the server sends a response.
+    pub fn get_next_blockhash(&mut self, previous_blockhash: &Hash) -> Hash {
+        self.get_next_blockhash_ext(previous_blockhash, &|| {
+            sleep(Duration::from_millis(100));
+        })
+    }
+    pub fn get_next_blockhash_ext(&mut self, previous_blockhash: &Hash, func: &Fn()) -> Hash {
+        loop {
+            let blockhash = self.get_recent_blockhash();
+            if blockhash != *previous_blockhash {
+                break blockhash;
+            }
+            debug!("Got same blockhash ({:?}), will retry...", blockhash);
+            func()
+        }
+    }
+
+    pub fn submit_poll_balance_metrics(elapsed: &Duration) {
+        solana_metrics::submit(
+            influxdb::Point::new("thinclient")
+                .add_tag("op", influxdb::Value::String("get_balance".to_string()))
+                .add_field(
+                    "duration_ms",
+                    influxdb::Value::Integer(timing::duration_as_ms(elapsed) as i64),
+                )
+                .to_owned(),
+        );
+    }
+
+    pub fn poll_balance_with_timeout(
+        &mut self,
+        pubkey: &Pubkey,
+        polling_frequency: &Duration,
+        timeout: &Duration,
+    ) -> io::Result<u64> {
+        let now = Instant::now();
+        loop {
+            match self.get_balance(&pubkey) {
+                Ok(bal) => {
+                    ThinClient::submit_poll_balance_metrics(&now.elapsed());
+                    return Ok(bal);
+                }
+                Err(e) => {
+                    sleep(*polling_frequency);
+                    if now.elapsed() > *timeout {
+                        ThinClient::submit_poll_balance_metrics(&now.elapsed());
+                        return Err(e);
+                    }
+                }
+            };
+        }
+    }
+
+    pub fn poll_get_balance(&mut self, pubkey: &Pubkey) -> io::Result<u64> {
+        self.poll_balance_with_timeout(pubkey, &Duration::from_millis(100), &Duration::from_secs(1))
+    }
+
+    /// Poll the server to confirm a transaction.
+    pub fn poll_for_signature(&mut self, signature: &Signature) -> io::Result<()> {
+        let now = Instant::now();
+        while !self.check_signature(signature) {
+            if now.elapsed().as_secs() > 15 {
+                // TODO: Return a better error.
+                return Err(io::Error::new(io::ErrorKind::Other, "signature not found"));
+            }
+            sleep(Duration::from_millis(250));
+        }
+        Ok(())
+    }
+
+    /// Check a signature in the bank. This method blocks
+    /// until the server sends a response.
+    pub fn check_signature(&mut self, signature: &Signature) -> bool {
+        trace!("check_signature: {:?}", signature);
+        let params = json!([format!("{}", signature)]);
+        let now = Instant::now();
+
+        loop {
+            let response = self.rpc_client.make_rpc_request(
+                1,
+                RpcRequest::ConfirmTransaction,
+                Some(params.clone()),
+            );
+
+            match response {
+                Ok(confirmation) => {
+                    let signature_status = confirmation.as_bool().unwrap();
+                    if signature_status {
+                        trace!("Response found signature");
+                    } else {
+                        trace!("Response signature not found");
+                    }
+                    solana_metrics::submit(
+                        influxdb::Point::new("thinclient")
+                            .add_tag("op", influxdb::Value::String("check_signature".to_string()))
+                            .add_field(
+                                "duration_ms",
+                                influxdb::Value::Integer(
+                                    timing::duration_as_ms(&now.elapsed()) as i64
+                                ),
+                            )
+                            .to_owned(),
+                    );
+                    return signature_status;
+                }
+                Err(err) => {
+                    debug!("check_signature request failed: {:?}", err);
+                }
+            };
+        }
+    }
+    pub fn fullnode_exit(&mut self) -> io::Result<bool> {
+        trace!("fullnode_exit sending request to {}", self.rpc_addr);
+        let response = self
+            .rpc_client
+            .make_rpc_request(1, RpcRequest::FullnodeExit, None)
+            .map_err(|error| {
+                debug!("Response from {} fullndoe_exit: {}", self.rpc_addr, error);
+                io::Error::new(io::ErrorKind::Other, "FullodeExit request failure")
+            })?;
+        serde_json::from_value(response).map_err(|error| {
+            debug!(
+                "ParseError: from {} fullndoe_exit: {}",
+                self.rpc_addr, error
+            );
+            io::Error::new(io::ErrorKind::Other, "FullodeExit parse failure")
+        })
+    }
+}
+
+impl Drop for ThinClient {
+    fn drop(&mut self) {
+        solana_metrics::flush();
+    }
+}
+
+pub fn retry_get_balance(
+    client: &mut ThinClient,
+    bob_pubkey: &Pubkey,
+    expected_balance: Option<u64>,
+) -> Option<u64> {
+    const LAST: usize = 30;
+    for run in 0..LAST {
+        let balance_result = client.poll_get_balance(bob_pubkey);
+        if expected_balance.is_none() {
+            return balance_result.ok();
+        }
+        trace!(
+            "retry_get_balance[{}] {:?} {:?}",
+            run,
+            balance_result,
+            expected_balance
+        );
+        if let (Some(expected_balance), Ok(balance_result)) = (expected_balance, balance_result) {
+            if expected_balance == balance_result {
+                return Some(balance_result);
+            }
+        }
+    }
+    None
+}