1250 - add NO_COLOR env var to disable logs colors (#1503)

Fix #1250

Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/garage/pulls/1503
Reviewed-by: Alex <lx@deuxfleurs.fr>

doc/book/reference-manual/configuration.md

@@ -175,6 +175,9 @@ they do not exist in the configuration file:
   Garage daemon send its logs to `journald` (using the native protocol of `systemd-journald`)
   instead of printing to stderr.
 
+- `NO_COLOR` (since `v2.4.0`): set this to `0` or `false` to disable
+  ANSI color codes in Garage's logs.
+
 The following environment variables can be used to override the corresponding
 values in the configuration file:
 

src/garage/main.rs

@@ -276,6 +276,11 @@ fn init_logging(opt: &Opt) {
 	tracing_subscriber::fmt()
 		.with_writer(std::io::stderr)
 		.with_env_filter(env_filter)
+		.with_ansi(
+			std::env::var("NO_COLOR")
+				.map(|x| x != "0" && !x.eq_ignore_ascii_case("false"))
+				.unwrap_or(true),
+		)
 		.init();
 }