Adds option to emit json structured logs to stdout

crates/librqbit/src/tracing_subscriber_config_utils.rs

@@ -52,7 +52,8 @@ impl std::io::Write for Writer {
 pub struct InitLoggingOptions<'a> {
     pub default_rust_log_value: Option<&'a str>,
     pub log_file: Option<&'a str>,
-    pub log_file_rust_log: Option<&'a str>,
+    pub log_file_rust_log: &'a str,
+    pub structured_stdout: bool,
 }
 
 pub struct InitLoggingResult {
@@ -107,7 +108,25 @@ pub fn init_logging(opts: InitLoggingOptions) -> anyhow::Result<InitLoggingResul
                     .with_writer(log_file)
                     .with_filter(
                         EnvFilter::builder()
-                            .parse(opts.log_file_rust_log.unwrap_or("info,librqbit=debug"))
+                            .parse(opts.log_file_rust_log)
+                            .context("can't parse log-file-rust-log")?,
+                    ),
+            )
+            .try_init()
+            .context("can't init logging")?;
+    } else if opts.structured_stdout {
+        // Use JSON logging to stdout
+        layered
+            .with(
+                fmt::layer()
+                    .with_ansi(false)
+                    .json()
+                    .with_current_span(true)
+                    .with_target(true)
+                    .with_writer(std::io::stdout)
+                    .with_filter(
+                        EnvFilter::builder()
+                            .parse(opts.log_file_rust_log)
                             .context("can't parse log-file-rust-log")?,
                     ),
             )

crates/rqbit/src/main.rs

@@ -38,6 +38,10 @@ struct Opts {
     #[arg(long = "log-file-rust-log", default_value = "librqbit=trace,info")]
     log_file_rust_log: String,
 
+    /// Use structured logging when emitting to stdout
+    #[arg(long = "structured-stdout", default_value_t = false)]
+    structured_stdout: bool,
+
     /// The interval to poll trackers, e.g. 30s.
     /// Trackers send the refresh interval when we connect to them. Often this is
     /// pretty big, e.g. 30 minutes. This can force a certain value.
@@ -251,7 +255,8 @@ async fn async_main(opts: Opts) -> anyhow::Result<()> {
             LogLevel::Error => "error",
         }),
         log_file: opts.log_file.as_deref(),
-        log_file_rust_log: Some(&opts.log_file_rust_log),
+        log_file_rust_log: &opts.log_file_rust_log,
+        structured_stdout: opts.structured_stdout,
     })?;
 
     match librqbit::try_increase_nofile_limit() {