Allow to disable colors through env vars

- unless forced, only use colors in tty
- support CLICOLOR and NO_COLOR vars
- switch to termcolor crate to handle output coloring

Cargo.lock

@@ -756,16 +756,18 @@ name = "gutenberg"
 version = "0.4.2"
 dependencies = [
  "actix-web 0.7.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "chrono 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "content 0.1.0",
  "ctrlc 3.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "errors 0.1.0",
  "front_matter 0.1.0",
+ "lazy_static 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "notify 4.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "rebuild 0.1.0",
  "site 0.1.0",
- "term-painter 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "termcolor 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "toml 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 1.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "utils 0.1.0",
@@ -2182,20 +2184,11 @@ dependencies = [
 ]
 
 [[package]]
-name = "term"
-version = "0.4.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "term-painter"
-version = "0.2.4"
+name = "termcolor"
+version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "term 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "wincolor 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2721,6 +2714,15 @@ name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "wincolor"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi-util 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "winreg"
 version = "0.5.1"
@@ -2998,8 +3000,7 @@ dependencies = [
 "checksum tempfile 3.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "55c1195ef8513f3273d55ff59fe5da6940287a0d7a98331254397f464833675b"
 "checksum tendril 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "9de21546595a0873061940d994bbbc5c35f024ae4fd61ec5c5b159115684f508"
 "checksum tera 0.11.16 (registry+https://github.com/rust-lang/crates.io-index)" = "4f79f17fe555fffe4838a082a63636883ee13022888dc7bdc99edad8e0a411cd"
-"checksum term 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "fa63644f74ce96fbeb9b794f66aff2a52d601cbd5e80f4b97123e3899f4570f1"
-"checksum term-painter 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "dcaa948f0e3e38470cd8dc8dcfe561a75c9e43f28075bb183845be2b9b3c08cf"
+"checksum termcolor 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "4096add70612622289f2fdcdbd5086dc81c1e2675e6ae58d6c4f62a16c6d7f2f"
 "checksum termion 1.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "689a3bdfaab439fd92bc87df5c4c78417d3cbe537487274e9b0b2dce76e92096"
 "checksum textwrap 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "307686869c93e71f94da64286f9a9524c0f308a9e1c87a583de8e9c9039ad3f6"
 "checksum thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "c6b53e329000edc2b34dbe8545fd20e55a333362d0a321909685a19bd28c3f1b"
@@ -3057,6 +3058,7 @@ dependencies = [
 "checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 "checksum winapi-util 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "afc5508759c5bf4285e61feb862b6083c8480aec864fa17a81fdec6f69b461ab"
 "checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+"checksum wincolor 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "561ed901ae465d6185fa7864d63fbd5720d0ef718366c9a4dc83cf6170d7e9ba"
 "checksum winreg 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a27a759395c1195c4cc5cda607ef6f8f6498f64e78f7900f5de0a127a424704a"
 "checksum winutil 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7daf138b6b14196e3830a588acf1e86966c694d3e8fb026fb105b8b5dca07e6e"
 "checksum ws 0.7.8 (registry+https://github.com/rust-lang/crates.io-index)" = "d2c221321dca56e6a80aa179d562e1fbe6ae116aeaa9205c76fa64e9e3c49dfc"

Cargo.toml

@@ -17,10 +17,12 @@ clap = "2"
 name = "gutenberg"
 
 [dependencies]
+atty = "0.2.11"
 clap = "2"
 chrono = "0.4"
+lazy_static = "1.1.0"
 toml = "0.4"
-term-painter = "0.2"
+termcolor = "1.0.4"
 # Used in init to ensure the url given as base_url is a valid one
 url = "1.5"
 # Below is for the serve cmd

docs/content/documentation/getting-started/cli-usage.md

@@ -77,3 +77,18 @@ You can also point to another config file than `config.toml` like so - the posit
 ```bash
 $ gutenberg --config config.staging.toml serve
 ```
+
+## Colored output
+
+Any of the three commands will emit colored output if your terminal supports it.
+
+*Note*: coloring is automatically disabled when the output is redirected to a pipe or a file (ie. when the standard output is not a TTY).
+
+You can disable this behavior by exporting one of the two following environment variables:
+
+- `NO_COLOR` (the value does not matter)
+- `CLICOLOR=0`
+
+Should you want to force the use of colors, you can set the following environment variable:
+
+- `CLICOLOR_FORCE=1`

src/console.rs

@@ -1,27 +1,48 @@
+use std::env;
+use std::io::Write;
 use std::time::Instant;
 
+use atty;
 use chrono::Duration;
-use term_painter::ToStyle;
-use term_painter::Color::*;
+use termcolor::{Color, ColorChoice, ColorSpec, StandardStream, WriteColor};
 
 use errors::Error;
 use site::Site;
 
+lazy_static! {
+    /// Termcolor color choice.
+    /// We do not rely on ColorChoice::Auto behavior
+    /// as the check is already performed by has_color.
+    static ref COLOR_CHOICE: ColorChoice = 
+        if has_color() {
+            ColorChoice::Always
+        } else {
+            ColorChoice::Never
+        };
+}
+
 
 pub fn info(message: &str) {
-    println!("{}", NotSet.bold().paint(message));
+    colorize(message, ColorSpec::new().set_bold(true));
 }
 
 pub fn warn(message: &str) {
-    println!("{}", Yellow.bold().paint(message));
+    colorize(message, ColorSpec::new().set_bold(true).set_fg(Some(Color::Yellow)));
 }
 
 pub fn success(message: &str) {
-    println!("{}", Green.bold().paint(message));
+    colorize(message, ColorSpec::new().set_bold(true).set_fg(Some(Color::Green)));
 }
 
 pub fn error(message: &str) {
-    println!("{}", Red.bold().paint(message));
+    colorize(message, ColorSpec::new().set_bold(true).set_fg(Some(Color::Red)));
+}
+
+/// Print a colorized message to stdout
+fn colorize(message: &str, color: &ColorSpec) {
+    let mut stdout = StandardStream::stdout(*COLOR_CHOICE);
+    stdout.set_color(color).unwrap();
+    writeln!(&mut stdout, "{}", message).unwrap();
 }
 
 /// Display in the console the number of pages/sections in the site
@@ -75,3 +96,11 @@ pub fn unravel_errors(message: &str, error: &Error) {
         self::error(&format!("Reason: {}", e));
     }
 }
+
+/// Check whether to output colors
+fn has_color() -> bool {
+    let use_colors = env::var("CLICOLOR").unwrap_or("1".to_string()) != "0" && !env::var("NO_COLOR").is_ok();
+    let force_colors = env::var("CLICOLOR_FORCE").unwrap_or("0".to_string()) != "0";
+
+    force_colors || use_colors && atty::is(atty::Stream::Stdout)
+}

src/main.rs

@@ -1,9 +1,12 @@
+extern crate atty;
 extern crate actix_web;
 #[macro_use]
 extern crate clap;
 extern crate chrono;
+#[macro_use]
+extern crate lazy_static;
 extern crate notify;
-extern crate term_painter;
+extern crate termcolor;
 extern crate url;
 extern crate ws;
 extern crate ctrlc;