commit 32fc54e7fc2db2e4f68d7bf96ab0e46c66d0de6e
parent 0412d20a31c0b49199f4d418611d40f512aa368a
Author: Antoine A <>
Date: Tue, 25 Jan 2022 14:34:45 +0100
Break long function in two and other improvements
Diffstat:
8 files changed, 343 insertions(+), 198 deletions(-)
diff --git a/Cargo.lock b/Cargo.lock
@@ -799,9 +799,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
[[package]]
name = "libc"
-version = "0.2.113"
+version = "0.2.114"
source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "eef78b64d87775463c549fbd80e19249ef436ea3bf1de2a1eb7e717ec7fab1e9"
+checksum = "b0005d08a8f7b65fb8073cb697aa0b12b631ed251ce73d862ce50eeb52ce3b50"
[[package]]
name = "listenfd"
diff --git a/README.md b/README.md
@@ -51,7 +51,7 @@ Modules have specific configuration:
```
┌─────┐ ┌────────────────┐ ┌──────────┐
- │Taler├───┤Depolymerization├───┤Blockchain│
+ │Taler│◄─►│Depolymerization│◄─►│Blockchain│
└─────┘ └────────────────┘ └──────────┘
```
@@ -59,6 +59,6 @@ Modules have specific configuration:
```
┌────────────┐ ┌──────────┐ ┌────────┐
- │wire_gateway├───┤PostgreSQL├───┤###_wire│
+ │wire_gateway│◄─►│PostgreSQL│◄─►│###_wire│
└────────────┘ └──────────┘ └────────┘
```
\ No newline at end of file
diff --git a/btc-wire/src/loops.rs b/btc-wire/src/loops.rs
@@ -19,7 +19,7 @@ use btc_wire::rpc;
use crate::fail_point::Injected;
pub mod analysis;
-pub mod listener;
+pub mod watcher;
pub mod worker;
#[derive(Debug, thiserror::Error)]
diff --git a/btc-wire/src/loops/listener.rs b/btc-wire/src/loops/listener.rs
@@ -1,35 +0,0 @@
-/*
- This file is part of TALER
- Copyright (C) 2022 Taler Systems SA
-
- TALER is free software; you can redistribute it and/or modify it under the
- terms of the GNU Affero General Public License as published by the Free Software
- Foundation; either version 3, or (at your option) any later version.
-
- TALER is distributed in the hope that it will be useful, but WITHOUT ANY
- WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
- A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.
-
- You should have received a copy of the GNU Affero General Public License along with
- TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
-*/
-use taler_common::log::log::error;
-
-use crate::reconnect::{AutoReconnectRPC, AutoReconnectSql};
-
-use super::LoopResult;
-
-/// Wait for new block and notify arrival with postgreSQL notifications
-pub fn block_listener(mut rpc: AutoReconnectRPC, mut db: AutoReconnectSql) {
- loop {
- let rpc = rpc.client();
- let db = db.client();
- let result: LoopResult<()> = (|| loop {
- rpc.wait_for_new_block(0)?;
- db.execute("NOTIFY new_block", &[])?;
- })();
- if let Err(e) = result {
- error!("listener: {}", e);
- }
- }
-}
diff --git a/btc-wire/src/loops/watcher.rs b/btc-wire/src/loops/watcher.rs
@@ -0,0 +1,35 @@
+/*
+ This file is part of TALER
+ Copyright (C) 2022 Taler Systems SA
+
+ TALER is free software; you can redistribute it and/or modify it under the
+ terms of the GNU Affero General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License along with
+ TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
+*/
+use taler_common::log::log::error;
+
+use crate::reconnect::{AutoReconnectRPC, AutoReconnectSql};
+
+use super::LoopResult;
+
+/// Wait for new block and notify arrival with postgreSQL notifications
+pub fn watcher(mut rpc: AutoReconnectRPC, mut db: AutoReconnectSql) {
+ loop {
+ let rpc = rpc.client();
+ let db = db.client();
+ let result: LoopResult<()> = (|| loop {
+ rpc.wait_for_new_block(0)?;
+ db.execute("NOTIFY new_block", &[])?;
+ })();
+ if let Err(e) = result {
+ error!("watcher: {}", e);
+ }
+ }
+}
diff --git a/btc-wire/src/loops/worker.rs b/btc-wire/src/loops/worker.rs
@@ -22,7 +22,7 @@ use std::{
use bitcoin::{hashes::Hash, Amount as BtcAmount, BlockHash, Txid};
use btc_wire::{
- rpc::{self, BtcRpc, Category, ErrorCode},
+ rpc::{self, BtcRpc, Category, ErrorCode, TransactionFull},
rpc_utils::sender_address,
GetOpReturnErr, GetSegwitErr,
};
@@ -142,7 +142,7 @@ fn send(db: &mut Client, rpc: &mut BtcRpc, status: TxStatus) -> LoopResult<bool>
assert!(status == TxStatus::Delayed || status == TxStatus::Requested);
// We rely on the advisory lock to ensure we are the only one sending transactions
let row = db.query_opt(
- "SELECT id, amount, wtid, credit_acc, exchange_url FROM tx_out WHERE status=$1 LIMIT 1",
+ "SELECT id, amount, wtid, credit_acc, exchange_url FROM tx_out WHERE status=$1 ORDER BY _date LIMIT 1",
&[&(status as i16)],
)?;
if let Some(row) = &row {
@@ -186,7 +186,7 @@ fn bounce(
assert!(status == BounceStatus::Delayed || status == BounceStatus::Requested);
// We rely on the advisory lock to ensure we are the only one sending transactions
let row = db.query_opt(
- "SELECT id, bounced FROM bounce WHERE status=$1 LIMIT 1",
+ "SELECT id, bounced FROM bounce WHERE status=$1 ORDER BY _date LIMIT 1",
&[&(status as i16)],
)?;
if let Some(row) = &row {
@@ -405,168 +405,193 @@ fn sync_chain_outgoing(
{
Ok((full, Ok(info))) => match info {
Info::Transaction { wtid, .. } => {
- let credit_addr = full.details[0].address.as_ref().unwrap();
- let amount = btc_to_taler(&full.amount);
-
- if confirmations < 0 {
- if full.replaced_by_txid.is_none() {
- // Handle conflicting tx
- let nb_row = db.execute(
- "UPDATE tx_out SET status=$1, txid=NULL where txid=$2",
- &[&(TxStatus::Delayed as i16), &id.as_ref()],
- )?;
- if nb_row > 0 {
- warn!(
- ">> (conflict) {} in {} to {}",
- base32(&wtid),
- id,
- credit_addr
- );
- }
- }
- } else {
- // Get previous out tx
- let row = db.query_opt(
- "SELECT id, status, txid FROM tx_out WHERE wtid=$1 FOR UPDATE",
- &[&wtid.as_ref()],
+ sync_chain_outgoing_send(id, &full, &wtid, rpc, db, confirmations, config)?
+ }
+ Info::Bounce { bounced } => {
+ sync_chain_outgoing_bounce(id, &bounced, db, confirmations)?
+ }
+ },
+ Ok((_, Err(e))) => warn!("send: decode-info {} - {}", id, e),
+ Err(e) => match e {
+ GetOpReturnErr::MissingOpReturn => { /* Ignore */ }
+ GetOpReturnErr::RPC(e) => return Err(e)?,
+ },
+ }
+ Ok(())
+}
+
+/// Sync database with an outgoing send transaction
+fn sync_chain_outgoing_send(
+ id: &Txid,
+ full: &TransactionFull,
+ wtid: &[u8; 32],
+ rpc: &mut BtcRpc,
+ db: &mut Client,
+ confirmations: i32,
+ config: &Config,
+) -> LoopResult<()> {
+ let credit_addr = full.details[0].address.as_ref().unwrap();
+ let amount = btc_to_taler(&full.amount);
+
+ if confirmations < 0 {
+ if full.replaced_by_txid.is_none() {
+ // Handle conflicting tx
+ let nb_row = db.execute(
+ "UPDATE tx_out SET status=$1, txid=NULL where txid=$2",
+ &[&(TxStatus::Delayed as i16), &id.as_ref()],
+ )?;
+ if nb_row > 0 {
+ warn!(
+ ">> (conflict) {} in {} to {}",
+ base32(wtid),
+ id,
+ credit_addr
+ );
+ }
+ }
+ } else {
+ // Get previous out tx
+ let row = db.query_opt(
+ "SELECT id, status, txid FROM tx_out WHERE wtid=$1 FOR UPDATE",
+ &[&wtid.as_ref()],
+ )?;
+ if let Some(row) = row {
+ // If already in database, sync status
+ let row_id: i32 = row.get(0);
+ let status: i16 = row.get(1);
+ match TxStatus::try_from(status as u8).unwrap() {
+ TxStatus::Requested | TxStatus::Delayed => {
+ let nb_row = db.execute(
+ "UPDATE tx_out SET status=$1, txid=$2 WHERE id=$3 AND status=$4",
+ &[&(TxStatus::Sent as i16), &id.as_ref(), &row_id, &status],
)?;
- if let Some(row) = row {
- // If already in database sync status
- let row_id: i32 = row.get(0);
- let status: i16 = row.get(1);
- match TxStatus::try_from(status as u8).unwrap() {
- TxStatus::Requested | TxStatus::Delayed => {
- let nb_row = db.execute(
- "UPDATE tx_out SET status=$1, txid=$2 WHERE id=$3 AND status=$4",
- &[&(TxStatus::Sent as i16), &id.as_ref(), &row_id, &status],
- )?;
- if nb_row > 0 {
- warn!(
- ">> (recovered) {} {} in {} to {}",
- amount,
- base32(&wtid),
- id,
- credit_addr
- );
- }
- }
- TxStatus::Sent => {
- if let Some(txid) = full.replaces_txid {
- let stored_id = sql_txid(&row, 2);
- if txid == stored_id {
- let nb_row = db.execute(
- "UPDATE tx_out SET txid=$1 WHERE txid=$2",
- &[&id.as_ref(), &txid.as_ref()],
- )?;
- if nb_row > 0 {
- info!(
- ">> (recovered) {} replace {} with {}",
- base32(&wtid),
- txid,
- id
- );
- }
- }
- }
- }
- }
- } else {
- // Else add to database
- let debit_addr = sender_address(rpc, &full)?;
- let date = SystemTime::UNIX_EPOCH + Duration::from_secs(full.time);
- let nb = db.execute(
- "INSERT INTO tx_out (_date, amount, wtid, debit_acc, credit_acc, exchange_url, status, txid, request_uid) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9) ON CONFLICT (wtid) DO NOTHING",
- &[&date, &amount.to_string(), &wtid.as_ref(), &btc_payto_url(&debit_addr).as_ref(), &btc_payto_url(credit_addr).as_ref(), &config.base_url.as_ref(), &(TxStatus::Sent as i16), &id.as_ref(), &None::<&[u8]>],
- )?;
- if nb > 0 {
- warn!(
- ">> (onchain) {} {} in {} to {}",
- amount,
- base32(&wtid),
- id,
- credit_addr
- );
- }
+ if nb_row > 0 {
+ warn!(
+ ">> (recovered) {} {} in {} to {}",
+ amount,
+ base32(wtid),
+ id,
+ credit_addr
+ );
}
-
- if let Some(delay) = config.bump_delay {
- if confirmations == 0 && full.replaced_by_txid.is_none() {
- let now = SystemTime::now()
- .duration_since(SystemTime::UNIX_EPOCH)
- .unwrap()
- .as_secs();
- if now - full.time > delay as u64 {
- let bump = rpc.bump_fee(id)?;
- fail_point("(injected) fail bump", 0.3)?;
- db.execute(
- "UPDATE tx_out SET txid=$1 WHERE txid=$2",
- &[&bump.txid.as_ref(), &id.as_ref()],
- )?;
+ }
+ TxStatus::Sent => {
+ if let Some(txid) = full.replaces_txid {
+ let stored_id = sql_txid(&row, 2);
+ if txid == stored_id {
+ let nb_row = db.execute(
+ "UPDATE tx_out SET txid=$1 WHERE txid=$2",
+ &[&id.as_ref(), &txid.as_ref()],
+ )?;
+ if nb_row > 0 {
info!(
- ">> (bump) {} replace {} with {}",
- base32(&wtid),
- id,
- bump.txid
+ ">> (recovered) {} replace {} with {}",
+ base32(wtid),
+ txid,
+ id
);
}
}
}
}
}
- Info::Bounce { bounced } => {
- if confirmations < 0 {
- // Handle conflicting tx
+ } else {
+ // Else add to database
+ let debit_addr = sender_address(rpc, &full)?;
+ let date = SystemTime::UNIX_EPOCH + Duration::from_secs(full.time);
+ let nb = db.execute(
+ "INSERT INTO tx_out (_date, amount, wtid, debit_acc, credit_acc, exchange_url, status, txid, request_uid) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9) ON CONFLICT (wtid) DO NOTHING",
+ &[&date, &amount.to_string(), &wtid.as_ref(), &btc_payto_url(&debit_addr).as_ref(), &btc_payto_url(credit_addr).as_ref(), &config.base_url.as_ref(), &(TxStatus::Sent as i16), &id.as_ref(), &None::<&[u8]>],
+ )?;
+ if nb > 0 {
+ warn!(
+ ">> (onchain) {} {} in {} to {}",
+ amount,
+ base32(wtid),
+ id,
+ credit_addr
+ );
+ }
+ }
+
+ if let Some(delay) = config.bump_delay {
+ if confirmations == 0 && full.replaced_by_txid.is_none() {
+ let now = SystemTime::now()
+ .duration_since(SystemTime::UNIX_EPOCH)
+ .unwrap()
+ .as_secs();
+ if now - full.time > delay as u64 {
+ let bump = rpc.bump_fee(id)?;
+ fail_point("(injected) fail bump", 0.3)?;
+ db.execute(
+ "UPDATE tx_out SET txid=$1 WHERE txid=$2",
+ &[&bump.txid.as_ref(), &id.as_ref()],
+ )?;
+ info!(
+ ">> (bump) {} replace {} with {}",
+ base32(wtid),
+ id,
+ bump.txid
+ );
+ }
+ }
+ }
+ }
+ Ok(())
+}
+
+/// Sync database with an outgoing bounce transaction
+fn sync_chain_outgoing_bounce(
+ id: &Txid,
+ bounced: &Txid,
+ db: &mut Client,
+ confirmations: i32,
+) -> LoopResult<()> {
+ if confirmations < 0 {
+ // Handle conflicting tx
+ let nb_row = db.execute(
+ "UPDATE bounce SET status=$1, txid=NULL where txid=$2",
+ &[&(BounceStatus::Delayed as i16), &id.as_ref()],
+ )?;
+ if nb_row > 0 {
+ warn!("|| (conflict) {} in {}", &bounced, &id);
+ }
+ } else {
+ // Get previous bounce
+ let row = db.query_opt(
+ "SELECT id, status FROM bounce WHERE bounced=$1",
+ &[&bounced.as_ref()],
+ )?;
+ if let Some(row) = row {
+ // If already in database, sync status
+ let row_id: i32 = row.get(0);
+ let status: i16 = row.get(1);
+ match BounceStatus::try_from(status as u8).unwrap() {
+ BounceStatus::Requested | BounceStatus::Delayed => {
let nb_row = db.execute(
- "UPDATE bounce SET status=$1, txid=NULL where txid=$2",
- &[&(BounceStatus::Delayed as i16), &id.as_ref()],
+ "UPDATE bounce SET status=$1, txid=$2 WHERE id=$3 AND status=$4",
+ &[&(BounceStatus::Sent as i16), &id.as_ref(), &row_id, &status],
)?;
if nb_row > 0 {
- warn!("|| (conflict) {} in {}", &bounced, &id);
- }
- } else {
- // Get previous bounce
- let row = db.query_opt(
- "SELECT id, status FROM bounce WHERE bounced=$1",
- &[&bounced.as_ref()],
- )?;
- if let Some(row) = row {
- // If already in database sync status
- let row_id: i32 = row.get(0);
- let status: i16 = row.get(1);
- match BounceStatus::try_from(status as u8).unwrap() {
- BounceStatus::Requested | BounceStatus::Delayed => {
- let nb_row = db.execute(
- "UPDATE bounce SET status=$1, txid=$2 WHERE id=$3 AND status=$4",
- &[&(BounceStatus::Sent as i16), &id.as_ref(), &row_id, &status],
- )?;
- if nb_row > 0 {
- warn!("|| (recovered) {} in {}", &bounced, &id);
- }
- }
- BounceStatus::Ignored => error!(
- "watcher: ignored bounce {} found in chain at {}",
- bounced, id
- ),
- BounceStatus::Sent => { /* Status is correct */ }
- }
- } else {
- // Else add to database
- let nb = db.execute(
- "INSERT INTO bounce (bounced, txid, status) VALUES ($1, $2, $3) ON CONFLICT (txid) DO NOTHING",
- &[&bounced.as_ref(), &id.as_ref(), &(BounceStatus::Sent as i16)],
- )?;
- if nb > 0 {
- warn!("|| (onchain) {} in {}", &bounced, &id);
- }
+ warn!("|| (recovered) {} in {}", &bounced, &id);
}
}
+ BounceStatus::Ignored => error!(
+ "watcher: ignored bounce {} found in chain at {}",
+ bounced, id
+ ),
+ BounceStatus::Sent => { /* Status is correct */ }
}
- },
- Ok((_, Err(e))) => warn!("send: decode-info {} - {}", id, e),
- Err(e) => match e {
- GetOpReturnErr::MissingOpReturn => { /* Ignore */ }
- GetOpReturnErr::RPC(e) => return Err(e)?,
- },
+ } else {
+ // Else add to database
+ let nb = db.execute(
+ "INSERT INTO bounce (bounced, txid, status) VALUES ($1, $2, $3) ON CONFLICT (txid) DO NOTHING",
+ &[&bounced.as_ref(), &id.as_ref(), &(BounceStatus::Sent as i16)],
+ )?;
+ if nb > 0 {
+ warn!("|| (onchain) {} in {}", &bounced, &id);
+ }
+ }
}
Ok(())
}
diff --git a/btc-wire/src/main.rs b/btc-wire/src/main.rs
@@ -23,7 +23,7 @@ use reconnect::{AutoReconnectRPC, AutoReconnectSql};
use std::{sync::atomic::AtomicU16, thread::JoinHandle};
use taler_common::{config::Config, log::log::info};
-use crate::loops::{analysis::analysis, listener::block_listener, worker::worker};
+use crate::loops::{analysis::analysis, watcher::watcher, worker::worker};
mod fail_point;
mod info;
@@ -72,27 +72,27 @@ fn main() {
let mut rpc = BtcRpc::common(&btc_config).unwrap();
rpc.load_wallet(WIRE_WALLET_NAME).ok();
- let rpc_listener = AutoReconnectRPC::new(btc_config.clone(), WIRE_WALLET_NAME);
+ let rpc_watcher = AutoReconnectRPC::new(btc_config.clone(), WIRE_WALLET_NAME);
let rpc_analysis = AutoReconnectRPC::new(btc_config.clone(), WIRE_WALLET_NAME);
let rpc_worker = AutoReconnectRPC::new(btc_config, WIRE_WALLET_NAME);
- let db_listener = AutoReconnectSql::new(&config.db_url);
+ let db_watcher = AutoReconnectSql::new(&config.db_url);
let db_analysis = AutoReconnectSql::new(&config.db_url);
let db_worker = AutoReconnectSql::new(&config.db_url);
- named_spawn("listener".to_string(), move || {
- block_listener(rpc_listener, db_listener)
+ named_spawn("watcher", move || {
+ watcher(rpc_watcher, db_watcher)
});
- named_spawn("analysis".to_string(), move || {
+ named_spawn("analysis", move || {
analysis(rpc_analysis, db_analysis, config, state)
});
worker(rpc_worker, db_worker, config, state);
}
-pub fn named_spawn<F, T>(name: String, f: F) -> JoinHandle<T>
+pub fn named_spawn<F, T>(name: impl Into<String>, f: F) -> JoinHandle<T>
where
F: FnOnce() -> T,
F: Send + 'static,
T: Send + 'static,
{
- std::thread::Builder::new().name(name).spawn(f).unwrap()
+ std::thread::Builder::new().name(name.into()).spawn(f).unwrap()
}
diff --git a/docs/presentation.tex b/docs/presentation.tex
@@ -0,0 +1,119 @@
+\documentclass{beamer}
+
+\usetheme{default}
+
+\usepackage{tikz}
+\usetikzlibrary{positioning}
+
+\title{Depolymerization WIP}
+\subtitle{TODO}
+\author{TODO}
+\institute{TODO}
+\date{\today}
+
+\begin{document}
+
+\begin{frame}
+ \titlepage
+\end{frame}
+
+\begin{frame}{Outline}
+ \tableofcontents
+\end{frame}
+
+\begin{frame}{Introduction}{Blockchain}
+ \begin{block}{Common blockchain limitation}
+ \begin{itemize}
+ \item \textbf{Slow} limited amount of transaction per seconds
+ \item \textbf{Delayed} block and confirmation delay
+ \item \textbf{Expensive} transaction fees
+ \item \textbf{Privacy} pseudonym and noise
+ \item \textbf{Compatibility} multiple blockchain and transactions format
+ \end{itemize}
+ \end{block}
+
+ \begin{block}{Biggest cryptocurrencies}
+ \begin{itemize}
+ \item \textbf{BTC} Bitcoin
+ \item \textbf{ETH} Ethereum
+ \end{itemize}
+ \end{block}
+\end{frame}
+
+\begin{frame}{Introduction}{Related work}
+ \begin{block}{Centralization - Coinbase's off-chain sending}
+ \begin{itemize}
+ \item [$+$] Fast and cheap: off chain transaction
+ \item [$-$] Trust in Coinbase: privacy, security \& transparency
+ \end{itemize}
+ \end{block}
+ \begin{block}{Layering - Lightning Network}
+ \begin{itemize}
+ \item [$+$] Fast and cheap: off chain transaction
+ \item [$-$] Incompatible with Bitcoin: require setting up a Bidirectional Payment Channels
+ \item [$-$] Fraud attempts are mitigated via a complex penalty system
+ \end{itemize}
+ \end{block}
+\end{frame}
+
+\begin{frame}{Introduction}{Taler}
+ \begin{itemize}
+ \item [$-$] Trust exchange operator or auditors
+ \item [$+$] Fast and cheap, no blockchain
+ \item [$+$] Privacy when it can, transparency when it must (avoid tax evasion and money laundering)
+ \item [$+$] Currency agnostic
+ \end{itemize}
+\end{frame}
+
+\begin{frame}{Architecture}{Taler bridge to blockchain}
+ \begin{center}
+ \begin{tikzpicture}[
+ rect/.style={rectangle, draw=black},
+ sym/.style={<->, shorten >= 2pt, shorten <= 2pt}
+ ]
+ \node[rect](1) {Taler};
+ \node[rect, right= of 1](2) {Depolymerization};
+ \node[rect, right= of 2](3) {Blockchain};
+
+ \draw[sym] (1) -- (2);
+ \draw[sym] (2) -- (3);
+ \end{tikzpicture}
+ \end{center}
+\end{frame}
+
+\begin{frame}{Architecture}{depolymerization}
+ \begin{center}
+ \begin{tikzpicture}[
+ rect/.style={rectangle, draw=black},
+ sym/.style={<->, shorten >= 2pt, shorten <= 2pt}
+ ]
+ \node[rect](1) {Taler};
+ \node[rect, below= of 1](2) {wire\_gateway};
+ \node[rect, right= of 2](3) {PostgreSQL};
+ \node[rect, right= of 3](4) {btc\_wire};
+ \node[rect, above= of 4](5) {bitcoind};
+
+ \draw[sym] (1) -- node [midway, right] {\tiny HTTP} (2);
+ \draw[sym] (2) -- node [midway, above] {\tiny SQL} (3);
+ \draw[sym] (3) -- node [midway, above] {\tiny SQL} (4);
+ \draw[sym] (4) -- node [midway, left] {\tiny RPC} (5);
+ \end{tikzpicture}
+ \end{center}
+\end{frame}
+
+\begin{frame}{btc\_wire}{Architecture}
+ Three loops
+ Watcher: Notify other loops when a new block has been mined
+ Analyzer: Analyse blockchain to adapt defensively
+ Worker: Sync chain -> Send -> Bounce
+\end{frame}
+
+\begin{frame}{btc\_wire}{Features}
+ \begin{itemize}
+ \item Handle stuck transactions
+ \item Fork resilient
+ \item Adaptive confirmation
+ \end{itemize}
+\end{frame}
+
+\end{document}
+\ No newline at end of file
