chore: Do not use ANSI colorization if not connected to a tty (#5674)

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

Cargo.lock

@@ -5484,6 +5484,7 @@ dependencies = [
 name = "trogging"
 version = "0.1.0"
 dependencies = [
+ "atty",
  "clap",
  "logfmt",
  "observability_deps",

trogging/Cargo.toml

@@ -8,6 +8,7 @@ description = "IOx logging pipeline built upon tokio-tracing"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+atty = "0.2.14"
 clap = { version = "3", features = ["derive", "env"], optional = true }
 logfmt = { path = "../logfmt" }
 observability_deps = { path = "../observability_deps" }

trogging/src/lib.rs

@@ -52,7 +52,7 @@ pub enum Error {
 
 pub type Result<T, E = Error> = std::result::Result<T, E>;
 
-/// Builder for tracing and logging.
+/// Builder to configure tracing and logging.
 #[derive(Debug)]
 pub struct Builder<W = fn() -> io::Stdout> {
     log_format: LogFormat,
@@ -72,7 +72,8 @@ impl Default for Builder {
             default_log_filter: EnvFilter::try_new(Self::DEFAULT_LOG_FILTER).unwrap(),
             make_writer: io::stdout,
             with_target: true,
-            with_ansi: true,
+            // use ansi control codes for color if connected to a TTY
+            with_ansi: atty::is(atty::Stream::Stdout),
         }
     }
 }
@@ -185,7 +186,8 @@ where
 
     /// Enable/disable ANSI encoding for formatted events (i.e. colors).
     ///
-    /// Defaults to true. See [tracing_subscriber::fmt::Layer::with_ansi]
+    /// Defaults to true if connected to a TTY, false otherwise. See
+    /// [tracing_subscriber::fmt::Layer::with_ansi]
     pub fn with_ansi(self, with_ansi: bool) -> Self {
         Self { with_ansi, ..self }
     }