feat: file and advanced logging configuration for tracing

Cargo.toml

@@ -124,7 +124,7 @@ dns-over-https = ["shadowsocks-service/dns-over-https"]
 dns-over-h3 = ["shadowsocks-service/dns-over-h3"]
 
 # Enable logging output
-logging = ["log4rs", "tracing", "tracing-subscriber", "time"]
+logging = ["log4rs", "tracing", "tracing-subscriber", "time", "tracing-appender"]
 
 # Enable DNS-relay
 local-dns = ["local", "shadowsocks-service/local-dns"]
@@ -208,6 +208,7 @@ tracing-subscriber = { version = "0.3", optional = true, features = [
     "time",
     "local-time",
 ] }
+tracing-appender = { version = "0.2.3", optional = true, default-features = false }
 time = { version = "0.3", optional = true }
 
 serde = { version = "1.0", features = ["derive"] }

README.md

@@ -871,19 +871,54 @@ Example configuration:
     // Service configurations
     // Logger configuration
     "log": {
+        // Default log level to use, if not overridden by `writers`, default is `0`
         // Equivalent to `-v` command line option
         "level": 1,
+        // Default log format to use, if not overridden by `writers`
         "format": {
-            // Euiqvalent to `--log-without-time`
+            // Euiqvalent to `--log-without-time`, default is `false`
             "without_time": false,
         },
-        // Equivalent to `--log-config`
-        // More detail could be found in https://crates.io/crates/log4rs
-        "config_path": "/path/to/log4rs/config.yaml"
+        // Advanced logging configuration for configuring multiple writers
+        // A stdout writer will be configured by default.
+        // Set this to empty array `[]` to disable logging completely
+        "writers": [
+            {
+                // Configure a stdout writer
+                // The inner fields are optional, if not set, it will use the default values
+                // To minimally configure a stdout writer, simply write `"stdout": {}`.
+                "stdout": {
+                    "level": 2,
+                    "format": {
+                        "without_time": false,
+                    }
+                }
+            },
+            {
+                // Configure a file writer, useful when running as a Windows Service
+                "file": {
+                    // `level` and `format` can also be set here, if not set, it will use the default values
+
+                    // Required. Directory to store log files
+                    "directory": "/var/log/shadowsocks-rust",
+                    // Optional. Log rotation frequency, must be one of the following:
+                    // - never (default): This will result in log file located at `directory/prefix.suffix`
+                    // - daily: A new log file in the format of `directory/prefix.yyyy-MM-dd.suffix` will be created daily
+                    // - hourly: A new log file in the format of `directory/prefix.yyyy-MM-dd-HH.suffix` will be created hourly
+                    "rotation": "never",
+                    // Optional. Prefix of log file, default is one of `sslocal`, `ssserver`, `ssmanager` depending on the service being run.
+                    "prefix": "shadowsocks-rust",
+                    // Optional. Suffix of log file, default is `log`
+                    "suffix": "log",
+                    // Optional. If set, keeps the last N log files
+                    "max_files": 5
+                }
+            }
+        ]
     },
     // Runtime configuration
     "runtime": {
-        // single_thread or multi_thread
+        // `single_thread` or `multi_thread`
         "mode": "multi_thread",
         // Worker threads that are used in multi-thread runtime
         "worker_count": 10