Public color API

examples/custom_format.rs

@@ -4,7 +4,14 @@ Changing the default logging format.
 Before running this example, try setting the `MY_LOG_LEVEL` environment variable to `info`:
 
 ```no_run,shell
-$ export MY_LOG_LEVEL = 'info'
+$ export MY_LOG_LEVEL='info'
+```
+
+Also try setting the `MY_LOG_STYLE` environment variable to `never` to disable colors
+or `auto` to enable them:
+
+```no_run,shell
+$ export MY_LOG_STYLE=never
 ```
 
 If you want to control the logging output completely, see the `custom_logger` example.
@@ -14,20 +21,26 @@ If you want to control the logging output completely, see the `custom_logger` ex
 extern crate log;
 extern crate env_logger;
 
-use std::env;
 use std::io::Write;
 
+use env_logger::{Env, Builder, fmt};
+
 fn init_logger() {
-    let mut builder = env_logger::Builder::new();
+    let env = Env::default()
+        .filter("MY_LOG_LEVEL")
+        .write_style("MY_LOG_STYLE");
+
+    let mut builder = Builder::from_env(env);
 
     // Use a different format for writing log records
     builder.format(|buf, record| {
-        writeln!(buf, "My formatted log: {}", record.args())
-    });
+        let mut style = buf.style();
+        style.set_bg(fmt::Color::Yellow).set_bold(true);
 
-    if let Ok(s) = env::var("MY_LOG_LEVEL") {
-        builder.parse(&s);
-    }
+        let timestamp = buf.timestamp();
+
+        writeln!(buf, "My formatted log ({}): {}", timestamp, style.value(record.args()))
+    });
 
     builder.init();
 }

examples/custom_logger.rs

@@ -4,7 +4,14 @@ Using `env_logger` to drive a custom logger.
 Before running this example, try setting the `MY_LOG_LEVEL` environment variable to `info`:
 
 ```no_run,shell
-$ export MY_LOG_LEVEL = 'info'
+$ export MY_LOG_LEVEL='info'
+```
+
+Also try setting the `MY_LOG_STYLE` environment variable to `never` to disable colors
+or `auto` to enable them:
+
+```no_run,shell
+$ export MY_LOG_STYLE=never
 ```
 
 If you only want to change the way logs are formatted, look at the `custom_format` example.
@@ -23,13 +30,7 @@ struct MyLogger {
 impl MyLogger {
     fn new() -> MyLogger {
         use env_logger::filter::Builder;
-        let mut builder = Builder::new();
-
-        // Parse a directives string from an environment variable
-        // This uses the same format as `env_logger::Logger`
-        if let Ok(ref filter) = std::env::var("MY_LOG_LEVEL") {
-           builder.parse(filter);
-        }
+        let mut builder = Builder::from_env("MY_LOG_LEVEL");
 
         MyLogger {
             inner: builder.build()

examples/default.rs

@@ -4,7 +4,14 @@ Using `env_logger`.
 Before running this example, try setting the `MY_LOG_LEVEL` environment variable to `info`:
 
 ```no_run,shell
-$ export MY_LOG_LEVEL = 'info'
+$ export MY_LOG_LEVEL='info'
+```
+
+Also try setting the `MY_LOG_STYLE` environment variable to `never` to disable colors
+or `auto` to enable them:
+
+```no_run,shell
+$ export MY_LOG_STYLE=never
 ```
 */
 

src/filter/mod.rs

@@ -59,6 +59,7 @@
 //! [`Builder::parse`]: struct.Builder.html#method.parse
 //! [`Filter::matches`]: struct.Filter.html#method.matches
 
+use std::env;
 use std::mem;
 use std::fmt;
 use log::{Level, LevelFilter, Record, Metadata};
@@ -185,6 +186,17 @@ impl Builder {
         }
     }
 
+    /// Initializes the filter builder from an environment.
+    pub fn from_env(env: &str) -> Builder {
+        let mut builder = Builder::new();
+
+        if let Ok(s) = env::var(env) {
+            builder.parse(&s);
+        }
+
+        builder
+    }
+
     /// Adds a directive to the filter.
     ///
     /// The given module (if any) will log at most the specified level provided.
@@ -240,6 +252,12 @@ impl Builder {
     }
 }
 
+impl Default for Builder {
+    fn default() -> Self {
+        Builder::new()
+    }
+}
+
 impl fmt::Debug for Filter {
     fn fmt(&self, f: &mut fmt::Formatter)->fmt::Result {
         f.debug_struct("Filter")