[refactor](decoders): extract decoder logging into trx-decode-log crate

Move DecoderLoggers and DecodeLogsConfig out of trx-server into a
dedicated src/decoders/trx-decode-log crate, giving file logging the
same standalone crate treatment as the four decoder crates.

- src/decoders/trx-decode-log/ (new — DecodeLogsConfig + DecoderLoggers)
- trx-server/config.rs: re-exports DecodeLogsConfig from trx-decode-log
  so ServerConfig field references and all tests compile unchanged
- trx-server: drop decode_logs module, use trx_decode_log directly

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/decoders/trx-decode-log/Cargo.toml

@@ -0,0 +1,16 @@
+# SPDX-FileCopyrightText: 2026 Stanislaw Grams <stanislawgrams@gmail.com>
+#
+# SPDX-License-Identifier: BSD-2-Clause
+
+[package]
+name = "trx-decode-log"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+trx-core = { path = "../../trx-core" }
+chrono = { version = "0.4", default-features = false, features = ["clock"] }
+dirs = "6"
+serde = { workspace = true, features = ["derive"] }
+serde_json = { workspace = true }
+tracing = { workspace = true }

src/decoders/trx-decode-log/src/lib.rs

@@ -1,7 +1,12 @@
-// SPDX-FileCopyrightText: 2025 Stanislaw Grams <stanislawgrams@gmail.com>
+// SPDX-FileCopyrightText: 2026 Stanislaw Grams <stanislawgrams@gmail.com>
 //
 // SPDX-License-Identifier: BSD-2-Clause
 
+//! Server-side decoder file logging (APRS / CW / FT8 / WSPR).
+//!
+//! Provides [`DecodeLogsConfig`] for TOML configuration and [`DecoderLoggers`]
+//! for writing JSON-Lines log files with automatic daily rotation.
+
 use std::fs::{create_dir_all, File, OpenOptions};
 use std::io::{BufWriter, Write};
 use std::path::{Path, PathBuf};
@@ -9,12 +14,62 @@ use std::sync::{Arc, Mutex};
 use std::time::{SystemTime, UNIX_EPOCH};
 
 use chrono::Utc;
+use serde::{Deserialize, Serialize};
 use serde_json::json;
 use tracing::warn;
 
-use crate::config::DecodeLogsConfig;
 use trx_core::decode::{AprsPacket, CwEvent, Ft8Message, WsprMessage};
 
+// ---------------------------------------------------------------------------
+// Configuration
+// ---------------------------------------------------------------------------
+
+fn default_decode_logs_dir() -> String {
+    if let Some(data_dir) = dirs::data_dir() {
+        return data_dir
+            .join("trx-rs")
+            .join("decoders")
+            .to_string_lossy()
+            .to_string();
+    }
+    "logs/decoders".to_string()
+}
+
+/// Server-side decoder file logging configuration.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(default)]
+pub struct DecodeLogsConfig {
+    /// Whether decoder file logging is enabled
+    pub enabled: bool,
+    /// Base directory for log files
+    pub dir: String,
+    /// APRS decoder log filename
+    pub aprs_file: String,
+    /// CW decoder log filename
+    pub cw_file: String,
+    /// FT8 decoder log filename
+    pub ft8_file: String,
+    /// WSPR decoder log filename
+    pub wspr_file: String,
+}
+
+impl Default for DecodeLogsConfig {
+    fn default() -> Self {
+        Self {
+            enabled: false,
+            dir: default_decode_logs_dir(),
+            aprs_file: "TRXRS-APRS-%YYYY%-%MM%-%DD%.log".to_string(),
+            cw_file: "TRXRS-CW-%YYYY%-%MM%-%DD%.log".to_string(),
+            ft8_file: "TRXRS-FT8-%YYYY%-%MM%-%DD%.log".to_string(),
+            wspr_file: "TRXRS-WSPR-%YYYY%-%MM%-%DD%.log".to_string(),
+        }
+    }
+}
+
+// ---------------------------------------------------------------------------
+// File logger (private)
+// ---------------------------------------------------------------------------
+
 struct DecoderFileLogger {
     base_dir: PathBuf,
     file_template: String,
@@ -64,7 +119,7 @@ impl DecoderFileLogger {
         })
     }
 
-    fn write_payload<T: serde::Serialize>(&self, payload: &T) {
+    fn write_payload<T: Serialize>(&self, payload: &T) {
         let ts_ms = match SystemTime::now().duration_since(UNIX_EPOCH) {
             Ok(d) => d.as_millis() as u64,
             Err(_) => 0,
@@ -106,6 +161,11 @@ impl DecoderFileLogger {
     }
 }
 
+// ---------------------------------------------------------------------------
+// Public API
+// ---------------------------------------------------------------------------
+
+/// Aggregate logger for all four server-side decoders.
 pub struct DecoderLoggers {
     aprs: DecoderFileLogger,
     cw: DecoderFileLogger,
@@ -114,6 +174,7 @@ pub struct DecoderLoggers {
 }
 
 impl DecoderLoggers {
+    /// Create loggers from config, or return `None` when logging is disabled.
     pub fn from_config(cfg: &DecodeLogsConfig) -> Result<Option<Arc<Self>>, String> {
         if !cfg.enabled {
             return Ok(None);

src/trx-server/Cargo.toml

@@ -26,6 +26,7 @@ trx-backend = { path = "trx-backend" }
 trx-core = { path = "../trx-core" }
 trx-aprs = { path = "../decoders/trx-aprs" }
 trx-cw = { path = "../decoders/trx-cw" }
+trx-decode-log = { path = "../decoders/trx-decode-log" }
 trx-ft8 = { path = "../decoders/trx-ft8" }
 trx-wspr = { path = "../decoders/trx-wspr" }
 trx-protocol = { path = "../trx-protocol" }

src/trx-server/src/audio.rs

@@ -28,7 +28,7 @@ use trx_ft8::Ft8Decoder;
 use trx_wspr::WsprDecoder;
 
 use crate::config::AudioConfig;
-use crate::decode_logs::DecoderLoggers;
+use trx_decode_log::DecoderLoggers;
 
 const APRS_HISTORY_RETENTION: Duration = Duration::from_secs(24 * 60 * 60);
 const FT8_HISTORY_RETENTION: Duration = Duration::from_secs(24 * 60 * 60);

src/trx-server/src/config.rs

@@ -16,6 +16,7 @@ use std::path::{Path, PathBuf};
 
 use serde::{Deserialize, Serialize};
 use trx_app::{ConfigError, ConfigFile};
+pub use trx_decode_log::DecodeLogsConfig;
 
 use trx_core::rig::state::RigMode;
 
@@ -260,48 +261,6 @@ impl Default for AprsFiConfig {
     }
 }
 
-fn default_decode_logs_dir() -> String {
-    if let Some(data_dir) = dirs::data_dir() {
-        return data_dir
-            .join("trx-rs")
-            .join("decoders")
-            .to_string_lossy()
-            .to_string();
-    }
-    "logs/decoders".to_string()
-}
-
-/// Server-side decoder file logging configuration.
-#[derive(Debug, Clone, Serialize, Deserialize)]
-#[serde(default)]
-pub struct DecodeLogsConfig {
-    /// Whether decoder file logging is enabled
-    pub enabled: bool,
-    /// Base directory for log files
-    pub dir: String,
-    /// APRS decoder log filename
-    pub aprs_file: String,
-    /// CW decoder log filename
-    pub cw_file: String,
-    /// FT8 decoder log filename
-    pub ft8_file: String,
-    /// WSPR decoder log filename
-    pub wspr_file: String,
-}
-
-impl Default for DecodeLogsConfig {
-    fn default() -> Self {
-        Self {
-            enabled: false,
-            dir: default_decode_logs_dir(),
-            aprs_file: "TRXRS-APRS-%YYYY%-%MM%-%DD%.log".to_string(),
-            cw_file: "TRXRS-CW-%YYYY%-%MM%-%DD%.log".to_string(),
-            ft8_file: "TRXRS-FT8-%YYYY%-%MM%-%DD%.log".to_string(),
-            wspr_file: "TRXRS-WSPR-%YYYY%-%MM%-%DD%.log".to_string(),
-        }
-    }
-}
-
 impl ServerConfig {
     pub fn validate(&self) -> Result<(), String> {
         validate_log_level(self.general.log_level.as_deref())?;

src/trx-server/src/main.rs

@@ -5,7 +5,6 @@
 mod aprsfi;
 mod audio;
 mod config;
-mod decode_logs;
 mod error;
 mod listener;
 mod pskreporter;
@@ -34,7 +33,7 @@ use trx_core::rig::state::RigState;
 use trx_core::DynResult;
 
 use config::ServerConfig;
-use decode_logs::DecoderLoggers;
+use trx_decode_log::DecoderLoggers;
 
 const PKG_DESCRIPTION: &str = concat!(env!("CARGO_PKG_NAME"), " - rig server daemon");
 const RIG_TASK_CHANNEL_BUFFER: usize = 32;