let force the colors of regexp

Signed-off-by: Chmouel Boudjnah <chmouel@chmouel.com>

README.md

@@ -111,6 +111,12 @@ for input and snazzily print your logs from the stream (one line at a time).
   followed by a REGEXP and `snazy` will highlight it. You can have many `-r`
   switches with many regexps, and you get different highlight for each match.
 
+* If you want to have the highlight forced to some colors you can add the color at the begining of the regexp followed by a colon. The colors can be one of `yellow`, `red`, `green`, `blue`, `magenta`, `cyan`, `white`, `black`. For example if you want to highlight ERROR in red and WARNING in yellow you can do:
+
+```shell
+% kubectl log pod|snazy -r red:ERROR -r yellow:WARNING -r green:INFO
+```
+
 * If `snazy` don't recognize the line as json it will symply straight print
   it. Either way it will still apply regexp highlighting of the `-r` option or
   do the action commands matching (see below). This let you use it for any logs

src/cli.rs

@@ -131,7 +131,24 @@ fn regexp_colorize(regexps: &[String]) -> HashMap<String, Color> {
         Color::Blue,
     ];
     for (i, regexp) in regexps.iter().enumerate() {
-        regexp_colours.insert((*regexp).to_string(), colours[i % colours.len()]);
+        let mut chosen = colours[i % colours.len()];
+        let mut reg = regexp.to_string();
+        if let Some(colour) = regexp.split(':').next() {
+            // match colour in colours
+            chosen = match colour {
+                "yellow" => Color::Yellow,
+                "cyan" => Color::Cyan,
+                "red" => Color::Red,
+                "magenta" => Color::Magenta,
+                "blue" => Color::Blue,
+                "green" => Color::Green,
+                "white" => Color::White,
+                "black" => Color::Black,
+                _ => Color::Default,
+            };
+            reg = regexp.replace(format!("{colour}:").as_str(), "");
+        }
+        regexp_colours.insert(reg, chosen);
     }
     regexp_colours
 }