feat: control log ANSI output via boolean --log-with-ansi option (#543)

This PR adds support for controlling ANSI escape codes for colors and other text formatting when logging via a new boolean --log-with-ansi CLI option and its equivalent SERVER_LOG_WITH_ANSI env.

No ANSI by default:
Note that from now on, SWS will be no-ansi by default. If you want colored log output, then use --log-with-ansi.
For example:

```
static-web-server -p 8788 -d ./public/ -g trace -z --log-with-ansi
```

docs/content/configuration/environment-variables.md

@@ -27,6 +27,9 @@ Defines a grace period in seconds after a `SIGTERM` signal is caught which will
 ### SERVER_LOG_LEVEL
 Specify a logging level in lowercase. Possible values are `error`, `warn`, `info`, `debug` or `trace`. Default `error`.
 
+### SERVER_LOG_WITH_ANSI
+Enable or disable ANSI escape codes for colors and other text formatting of the log output.
+
 ### SERVER_LOG_REMOTE_ADDRESS
 Log incoming request information along with its Remote Address (IP) if available using the `info` log level. Default `false`.
 

docs/content/features/logging.md

@@ -15,6 +15,16 @@ static-web-server \
 
 > Note: The log format is not well defined and is subject to change.
 
+## Log output with ANSI
+
+SWS does not output ANSI escape codes by default. However, If you want ANSI escape for colors and other text formatting when logging then use the boolean `--log-with-ansi` CLI option and its equivalent [SERVER_LOG_WITH_ANSI](./../configuration/environment-variables.md#server_log_with_ansi) env.
+
+For example, if you want colored log output then use the `--log-with-ansi` option as follows:
+
+```sh
+static-web-server -p 8788 -d ./public/ -g trace -z --log-with-ansi
+```
+
 ## Log Remote Addresses
 
 SWS provides *Remote Address (IP)* logging for every request via an `INFO` log level.
@@ -76,6 +86,7 @@ Since the content of the `X-Forwarded-For` header can be changed by all proxies
 To restrict the logging to only requests that originate from trusted proxy IPs, you can use the `--trusted-proxies` option, or the equivalent [SERVER_TRUSTED_PROXIES](../configuration/environment-variables.md#server_trusted_proxies) env. This should be a list of IPs, separated by commas. An empty list (the default) indicates that all IPs should be trusted.
 
 Command used for the following examples:
+
 ```sh
 static-web-server -a "::" --log-forwarded-for=true --trusted-proxies="::1" -p 8080 -d docker/public/ -g info
 ```

src/logger.rs

@@ -12,25 +12,20 @@ use tracing_subscriber::{filter::Targets, fmt::format::FmtSpan, prelude::*};
 use crate::{Context, Result};
 
 /// Logging system initialization
-pub fn init(log_level: &str) -> Result {
+pub fn init(log_level: &str, log_with_ansi: bool) -> Result {
     let log_level = log_level.to_lowercase();
 
-    configure(&log_level).with_context(|| "failed to initialize logging")?;
+    configure(&log_level, log_with_ansi).with_context(|| "failed to initialize logging")?;
 
     Ok(())
 }
 
 /// Initialize logging builder with its levels.
-fn configure(level: &str) -> Result {
+fn configure(level: &str, enable_ansi: bool) -> Result {
     let level = level
         .parse::<Level>()
         .with_context(|| "failed to parse log level")?;
 
-    #[cfg(not(windows))]
-    let enable_ansi = true;
-    #[cfg(windows)]
-    let enable_ansi = false;
-
     let filtered_layer = tracing_subscriber::fmt::layer()
         .with_writer(std::io::stderr)
         .with_span_events(FmtSpan::CLOSE)

src/settings/cli.rs

@@ -123,6 +123,18 @@ pub struct General {
     /// Specify a logging level in lower case. Values: error, warn, info, debug or trace
     pub log_level: String,
 
+    #[arg(
+        long,
+        default_value = "false",
+        default_missing_value("true"),
+        num_args(0..=1),
+        require_equals(false),
+        action = clap::ArgAction::Set,
+        env = "SERVER_LOG_WITH_ANSI",
+    )]
+    /// Enable or disable ANSI escape codes for colors and other text formatting of the log output.
+    pub log_with_ansi: bool,
+
     #[arg(
         long,
         short = 'c',

src/settings/file.rs

@@ -205,8 +205,10 @@ pub struct General {
     /// Root directory path.
     pub root: Option<PathBuf>,
 
-    /// Logging.
+    /// Logging level.
     pub log_level: Option<LogLevel>,
+    /// Enable/disable ANSI escape codes for log output.
+    pub log_with_ansi: Option<bool>,
 
     /// Cache Control headers.
     pub cache_control_headers: Option<bool>,

src/settings/mod.rs

@@ -127,6 +127,7 @@ impl Settings {
         let mut port = opts.port;
         let mut root = opts.root;
         let mut log_level = opts.log_level;
+        let mut log_with_ansi = opts.log_with_ansi;
         let mut config_file = opts.config_file.clone();
         let mut cache_control_headers = opts.cache_control_headers;
 
@@ -242,6 +243,9 @@ impl Settings {
                 if let Some(ref v) = general.log_level {
                     log_level = v.name().to_lowercase();
                 }
+                if let Some(v) = general.log_with_ansi {
+                    log_with_ansi = v;
+                }
                 if let Some(v) = general.cache_control_headers {
                     cache_control_headers = v
                 }
@@ -414,7 +418,7 @@ impl Settings {
 
             // Logging system initialization in config file context
             if log_init {
-                logger::init(log_level.as_str())?;
+                logger::init(log_level.as_str(), log_with_ansi)?;
             }
 
             tracing::debug!("config file read successfully");
@@ -596,7 +600,7 @@ impl Settings {
             }
         } else if log_init {
             // Logging system initialization on demand
-            logger::init(log_level.as_str())?;
+            logger::init(log_level.as_str(), log_with_ansi)?;
         }
 
         Ok(Settings {
@@ -606,6 +610,7 @@ impl Settings {
                 port,
                 root,
                 log_level,
+                log_with_ansi,
                 config_file,
                 cache_control_headers,
                 #[cfg(any(