Introduce --json flag for the CLI

When `--json` is used the CLI does not log to file, but only on the command line in json output.

swap/src/bin/swap.rs

@@ -45,6 +45,7 @@ async fn main() -> Result<()> {
         env_config,
         data_dir,
         debug,
+        json,
         cmd,
     } = match parse_args_and_apply_defaults(env::args_os()) {
         Ok(args) => args,
@@ -76,7 +77,7 @@ async fn main() -> Result<()> {
         } => {
             let swap_id = Uuid::new_v4();
 
-            cli::tracing::init(debug, data_dir.join("logs"), swap_id)?;
+            cli::tracing::init(debug, json, data_dir.join("logs"), swap_id)?;
             let db = Database::open(data_dir.join("database").as_path())
                 .context("Failed to open database")?;
             let seed = Seed::from_file_or_generate(data_dir.as_path())
@@ -167,7 +168,7 @@ async fn main() -> Result<()> {
             monero_daemon_address,
             tor_socks5_port,
         } => {
-            cli::tracing::init(debug, data_dir.join("logs"), swap_id)?;
+            cli::tracing::init(debug, json, data_dir.join("logs"), swap_id)?;
             let db = Database::open(data_dir.join("database").as_path())
                 .context("Failed to open database")?;
             let seed = Seed::from_file_or_generate(data_dir.as_path())
@@ -232,7 +233,7 @@ async fn main() -> Result<()> {
             bitcoin_electrum_rpc_url,
             bitcoin_target_block,
         } => {
-            cli::tracing::init(debug, data_dir.join("logs"), swap_id)?;
+            cli::tracing::init(debug, json, data_dir.join("logs"), swap_id)?;
             let db = Database::open(data_dir.join("database").as_path())
                 .context("Failed to open database")?;
             let seed = Seed::from_file_or_generate(data_dir.as_path())
@@ -264,7 +265,7 @@ async fn main() -> Result<()> {
             bitcoin_electrum_rpc_url,
             bitcoin_target_block,
         } => {
-            cli::tracing::init(debug, data_dir.join("logs"), swap_id)?;
+            cli::tracing::init(debug, json, data_dir.join("logs"), swap_id)?;
             let db = Database::open(data_dir.join("database").as_path())
                 .context("Failed to open database")?;
             let seed = Seed::from_file_or_generate(data_dir.as_path())

swap/src/cli/command.rs

@@ -29,6 +29,7 @@ const DEFAULT_TOR_SOCKS5_PORT: &str = "9050";
 pub struct Arguments {
     pub env_config: env::Config,
     pub debug: bool,
+    pub json: bool,
     pub data_dir: PathBuf,
     pub cmd: Command,
 }
@@ -42,6 +43,7 @@ where
     let args = RawArguments::from_clap(&matches);
 
     let debug = args.debug;
+    let json = args.json;
     let is_testnet = args.testnet;
     let data = args.data;
 
@@ -63,6 +65,7 @@ where
         } => Ok(Arguments {
             env_config: env_config_from(is_testnet),
             debug,
+            json,
             data_dir: data::data_dir_from(data, is_testnet)?,
             cmd: Command::BuyXmr {
                 seller_peer_id,
@@ -86,6 +89,7 @@ where
         RawCommand::History => Ok(Arguments {
             env_config: env_config_from(is_testnet),
             debug,
+            json,
             data_dir: data::data_dir_from(data, is_testnet)?,
             cmd: Command::History,
         }),
@@ -106,6 +110,7 @@ where
         } => Ok(Arguments {
             env_config: env_config_from(is_testnet),
             debug,
+            json,
             data_dir: data::data_dir_from(data, is_testnet)?,
             cmd: Command::Resume {
                 swap_id,
@@ -134,6 +139,7 @@ where
         } => Ok(Arguments {
             env_config: env_config_from(is_testnet),
             debug,
+            json,
             data_dir: data::data_dir_from(data, is_testnet)?,
             cmd: Command::Cancel {
                 swap_id,
@@ -156,6 +162,7 @@ where
         } => Ok(Arguments {
             env_config: env_config_from(is_testnet),
             debug,
+            json,
             data_dir: data::data_dir_from(data, is_testnet)?,
             cmd: Command::Refund {
                 swap_id,
@@ -225,6 +232,13 @@ pub struct RawArguments {
     #[structopt(long, help = "Activate debug logging.")]
     pub debug: bool,
 
+    #[structopt(
+        short,
+        long = "json",
+        help = "Changes the log messages to json vs plain-text. This can be helpful to simplify automated log analyses."
+    )]
+    pub json: bool,
+
     #[structopt(subcommand)]
     pub cmd: RawCommand,
 }
@@ -765,11 +779,77 @@ mod tests {
         assert_eq!(args, Arguments::resume_testnet_defaults().with_debug());
     }
 
+    #[test]
+    fn given_with_json_then_json_set() {
+        let raw_ars = vec![
+            BINARY_NAME,
+            "--json",
+            "buy-xmr",
+            "--receive-address",
+            MONERO_MAINNET_ADDRESS,
+            "--seller-addr",
+            MUTLI_ADDRESS,
+            "--seller-peer-id",
+            PEER_ID,
+        ];
+
+        let args = parse_args_and_apply_defaults(raw_ars).unwrap();
+        assert_eq!(args, Arguments::buy_xmr_mainnet_defaults().with_json());
+
+        let raw_ars = vec![
+            BINARY_NAME,
+            "--testnet",
+            "--json",
+            "buy-xmr",
+            "--receive-address",
+            MONERO_STAGENET_ADDRESS,
+            "--seller-addr",
+            MUTLI_ADDRESS,
+            "--seller-peer-id",
+            PEER_ID,
+        ];
+
+        let args = parse_args_and_apply_defaults(raw_ars).unwrap();
+        assert_eq!(args, Arguments::buy_xmr_testnet_defaults().with_json());
+
+        let raw_ars = vec![
+            BINARY_NAME,
+            "--json",
+            "resume",
+            "--swap-id",
+            SWAP_ID,
+            "--receive-address",
+            MONERO_MAINNET_ADDRESS,
+            "--seller-addr",
+            MUTLI_ADDRESS,
+        ];
+
+        let args = parse_args_and_apply_defaults(raw_ars).unwrap();
+        assert_eq!(args, Arguments::resume_mainnet_defaults().with_json());
+
+        let raw_ars = vec![
+            BINARY_NAME,
+            "--testnet",
+            "--json",
+            "resume",
+            "--swap-id",
+            SWAP_ID,
+            "--receive-address",
+            MONERO_STAGENET_ADDRESS,
+            "--seller-addr",
+            MUTLI_ADDRESS,
+        ];
+
+        let args = parse_args_and_apply_defaults(raw_ars).unwrap();
+        assert_eq!(args, Arguments::resume_testnet_defaults().with_json());
+    }
+
     impl Arguments {
         pub fn buy_xmr_testnet_defaults() -> Self {
             Self {
                 env_config: env::Testnet::get_config(),
                 debug: false,
+                json: false,
                 data_dir: data_dir_path_cli().join(TESTNET),
                 cmd: Command::BuyXmr {
                     seller_peer_id: PeerId::from_str(PEER_ID).unwrap(),
@@ -789,6 +869,7 @@ mod tests {
             Self {
                 env_config: env::Mainnet::get_config(),
                 debug: false,
+                json: false,
                 data_dir: data_dir_path_cli().join(MAINNET),
                 cmd: Command::BuyXmr {
                     seller_peer_id: PeerId::from_str(PEER_ID).unwrap(),
@@ -807,6 +888,7 @@ mod tests {
             Self {
                 env_config: env::Testnet::get_config(),
                 debug: false,
+                json: false,
                 data_dir: data_dir_path_cli().join(TESTNET),
                 cmd: Command::Resume {
                     swap_id: Uuid::from_str(SWAP_ID).unwrap(),
@@ -826,6 +908,7 @@ mod tests {
             Self {
                 env_config: env::Mainnet::get_config(),
                 debug: false,
+                json: false,
                 data_dir: data_dir_path_cli().join(MAINNET),
                 cmd: Command::Resume {
                     swap_id: Uuid::from_str(SWAP_ID).unwrap(),
@@ -844,6 +927,7 @@ mod tests {
             Self {
                 env_config: env::Testnet::get_config(),
                 debug: false,
+                json: false,
                 data_dir: data_dir_path_cli().join(TESTNET),
                 cmd: Command::Cancel {
                     swap_id: Uuid::from_str(SWAP_ID).unwrap(),
@@ -859,6 +943,7 @@ mod tests {
             Self {
                 env_config: env::Mainnet::get_config(),
                 debug: false,
+                json: false,
                 data_dir: data_dir_path_cli().join(MAINNET),
                 cmd: Command::Cancel {
                     swap_id: Uuid::from_str(SWAP_ID).unwrap(),
@@ -873,6 +958,7 @@ mod tests {
             Self {
                 env_config: env::Testnet::get_config(),
                 debug: false,
+                json: false,
                 data_dir: data_dir_path_cli().join(TESTNET),
                 cmd: Command::Refund {
                     swap_id: Uuid::from_str(SWAP_ID).unwrap(),
@@ -888,6 +974,7 @@ mod tests {
             Self {
                 env_config: env::Mainnet::get_config(),
                 debug: false,
+                json: false,
                 data_dir: data_dir_path_cli().join(MAINNET),
                 cmd: Command::Refund {
                     swap_id: Uuid::from_str(SWAP_ID).unwrap(),
@@ -907,6 +994,11 @@ mod tests {
             self.debug = true;
             self
         }
+
+        pub fn with_json(mut self) -> Self {
+            self.json = true;
+            self
+        }
     }
 
     fn data_dir_path_cli() -> PathBuf {

swap/src/cli/tracing.rs

@@ -5,30 +5,48 @@ use tracing::{Event, Level, Subscriber};
 use tracing_subscriber::fmt::format::{DefaultFields, Format};
 use tracing_subscriber::fmt::time::ChronoLocal;
 use tracing_subscriber::layer::{Context, SubscriberExt};
-use tracing_subscriber::{fmt, EnvFilter, Layer, Registry};
+use tracing_subscriber::{fmt, EnvFilter, FmtSubscriber, Layer, Registry};
 use uuid::Uuid;
 
-pub fn init(debug: bool, dir: impl AsRef<Path>, swap_id: Uuid) -> Result<()> {
-    let level_filter = EnvFilter::try_new("swap=debug")?;
+pub fn init(debug: bool, json: bool, dir: impl AsRef<Path>, swap_id: Uuid) -> Result<()> {
+    if json {
+        let level = if debug { Level::DEBUG } else { Level::INFO };
 
-    let registry = Registry::default().with(level_filter);
+        let is_terminal = atty::is(atty::Stream::Stderr);
 
-    let appender = tracing_appender::rolling::never(dir, format!("swap-{}.log", swap_id));
-    let (appender, guard) = tracing_appender::non_blocking(appender);
+        FmtSubscriber::builder()
+            .with_env_filter(format!("swap={}", level))
+            .with_writer(std::io::stderr)
+            .with_ansi(is_terminal)
+            .with_timer(ChronoLocal::with_format("%F %T".to_owned()))
+            .with_target(false)
+            .json()
+            .init();
 
-    std::mem::forget(guard);
-
-    let file_logger = fmt::layer()
-        .with_ansi(false)
-        .with_target(false)
-        .with_writer(appender);
-
-    if debug {
-        set_global_default(registry.with(file_logger).with(debug_terminal_printer()))?;
+        Ok(())
     } else {
-        set_global_default(registry.with(file_logger).with(info_terminal_printer()))?;
+        let level_filter = EnvFilter::try_new("swap=debug")?;
+
+        let registry = Registry::default().with(level_filter);
+
+        let appender = tracing_appender::rolling::never(dir, format!("swap-{}.log", swap_id));
+        let (appender, guard) = tracing_appender::non_blocking(appender);
+
+        std::mem::forget(guard);
+
+        let file_logger = fmt::layer()
+            .with_ansi(false)
+            .with_target(false)
+            .with_writer(appender);
+
+        if debug {
+            set_global_default(registry.with(file_logger).with(debug_terminal_printer()))?;
+        } else {
+            set_global_default(registry.with(file_logger).with(info_terminal_printer()))?;
+        }
+
+        Ok(())
     }
-    Ok(())
 }
 
 pub struct StdErrPrinter<L> {