feat(package/prettify-log): colored output for log keywords

package/prettify-log/src/main.rs

@@ -1,45 +1,102 @@
 use std::io::{self, BufRead};
+use std::env;
 use serde_json::Value;
-use colored_json::ToColoredJson;
+use colored_json::{ColorMode, ToColoredJson};
+use regex::Regex;
 
-/// Finds the first '{' and tries to match nested braces until the
-/// corresponding '}'. Returns (start, end) byte offsets if found.
+/// Finds the first '{' and tries to match nested braces until the corresponding '}'.
 fn find_json_block(line: &str) -> Option<(usize, usize)> {
     let start = line.find('{')?;
     let mut brace_count = 0;
     for (i, ch) in line[start..].char_indices() {
-        if ch == '{' {
-            brace_count += 1;
-        } else if ch == '}' {
-            brace_count -= 1;
-            if brace_count == 0 {
-                // Return the byte-range of the entire JSON block
-                return Some((start, start + i + 1));
+        match ch {
+            '{' => brace_count += 1,
+            '}' => {
+                brace_count -= 1;
+                if brace_count == 0 {
+                    return Some((start, start + i + 1));
+                }
             }
+            _ => {}
         }
     }
     None
 }
 
-fn main() -> io::Result<()> {
-    let stdin = io::stdin();
+/// Applies color to known log keywords (e.g. ERROR, DEBUG) without coloring the colon.
+/// Captures the preceding boundary, the keyword, and the colon, then colors only the keyword.
+fn colorize_keywords(line: &str) -> String {
+    let red = "\x1b[31m";
+    let blue = "\x1b[34m";
+    let green = "\x1b[32m";
+    let yellow = "\x1b[33m";
+    let magenta = "\x1b[35m";
+    let cyan = "\x1b[36m";
+    let reset = "\x1b[0m";
 
+    let patterns = vec![
+        (Regex::new(r"(?i)(^|[^A-Za-z])(ERROR)(:)").unwrap(), format!("$1{red}$2{reset}$3", red=red, reset=reset)),
+        (Regex::new(r"(?i)(^|[^A-Za-z])(DEBUG)(:)").unwrap(), format!("$1{blue}$2{reset}$3", blue=blue, reset=reset)),
+        (Regex::new(r"(?i)(^|[^A-Za-z])(INFO)(:)").unwrap(), format!("$1{green}$2{reset}$3", green=green, reset=reset)),
+        (Regex::new(r"(?i)(^|[^A-Za-z])(LOG)(:)").unwrap(), format!("$1{green}$2{reset}$3", green=green, reset=reset)),
+        (Regex::new(r"(?i)(^|[^A-Za-z])(EXCEPTION)(:)").unwrap(), format!("$1{magenta}$2{reset}$3", magenta=magenta, reset=reset)),
+        (Regex::new(r"(?i)(^|[^A-Za-z])(WARNING)(:)").unwrap(), format!("$1{yellow}$2{reset}$3", yellow=yellow, reset=reset)),
+        (Regex::new(r"(?i)(^|[^A-Za-z])(NOTICE)(:)").unwrap(), format!("$1{cyan}$2{reset}$3", cyan=cyan, reset=reset)),
+        (Regex::new(r"(?i)(^|[^A-Za-z])(HINT)(:)").unwrap(), format!("$1{cyan}$2{reset}$3", cyan=cyan, reset=reset)),
+        (Regex::new(r"(?i)(^|[^A-Za-z])(FATAL)(:)").unwrap(), format!("$1{magenta}$2{reset}$3", magenta=magenta, reset=reset)),
+        (Regex::new(r"(?i)(^|[^A-Za-z])(DETAIL)(:)").unwrap(), format!("$1{cyan}$2{reset}$3", cyan=cyan, reset=reset)),
+        (Regex::new(r"(?i)(^|[^A-Za-z])(STATEMENT)(:)").unwrap(), format!("$1{cyan}$2{reset}$3", cyan=cyan, reset=reset)),
+    ];
+
+    let mut out = String::from(line);
+    for (re, replacement) in patterns {
+        // Replace all occurrences
+        out = re.replace_all(&out, replacement.as_str()).to_string();
+    }
+    out
+}
+
+fn conditionally_colorize_keywords<'a>(line: &'a str, force_color: bool) -> String {
+        if force_color {
+            colorize_keywords(&line)
+        } else if atty::is(atty::Stream::Stdout) {
+            colorize_keywords(&line)
+        } else {
+            line.to_string()
+        }
+}
+
+fn main() -> io::Result<()> {
+    let mut force_color = false;
+    for arg in env::args().skip(1) {
+        if arg == "--color-output" {
+            force_color = true;
+        }
+    }
+
+    let stdin = io::stdin();
     for line_result in stdin.lock().lines() {
         let line = line_result?;
         if let Some((start, end)) = find_json_block(&line) {
             let candidate = &line[start..end];
             if let Ok(json) = serde_json::from_str::<Value>(candidate) {
-                // Prettify and reconstruct the line
-                let pretty = serde_json::to_string_pretty(&json).unwrap().to_colored_json_auto().unwrap();
-                let prefix = &line[..start];
-                let suffix = &line[end..];
-                println!("{}{}{}", prefix, pretty, suffix);
+                let pretty = serde_json::to_string_pretty(&json).unwrap();
+
+                let colorized = if force_color {
+                    pretty.to_colored_json(ColorMode::On).unwrap()
+                } else {
+                    pretty.to_colored_json_auto().unwrap()
+                };
+
+                let prefix = conditionally_colorize_keywords(&line[..start], force_color);
+                let suffix = conditionally_colorize_keywords(&line[end..], force_color);
+                println!("{}{}{}", prefix, colorized, suffix);
                 continue;
             }
         }
-        // If no valid JSON found, print as-is
-        println!("{}", line);
-    }
 
+        // If no valid JSON found or parsing fails, print unchanged
+        println!("{}", conditionally_colorize_keywords(&line, force_color));
+    }
     Ok(())
 }