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

package/prettify-log/Cargo.lock

@@ -33,6 +33,17 @@ dependencies = [
  "wait-timeout",
 ]
 
+[[package]]
+name = "atty"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
+dependencies = [
+ "hermit-abi",
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.4.0"
@@ -122,6 +133,15 @@ dependencies = [
  "windows-targets",
 ]
 
+[[package]]
+name = "hermit-abi"
+version = "0.1.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62b467343b94ba476dcb2500d242dadbb39557df889310ac77c5d99100aaac33"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "itoa"
 version = "1.0.14"
@@ -202,9 +222,11 @@ name = "prettify-log"
 version = "0.1.0"
 dependencies = [
  "assert_cmd",
+ "atty",
  "colored_json",
  "float-cmp",
  "predicates",
+ "regex",
  "serde",
  "serde_json",
  "tempfile",
@@ -363,6 +385,28 @@ dependencies = [
  "wit-bindgen-rt",
 ]
 
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
 [[package]]
 name = "windows-sys"
 version = "0.59.0"

package/prettify-log/Cargo.toml

@@ -4,7 +4,9 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+atty = "0.2.14"
 colored_json = "5.0.0"
+regex = "1.11.1"
 serde = "1.0.217"
 serde_json = "1.0.138"
 

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 == '}' {
+        match ch {
+            '{' => brace_count += 1,
+            '}' => {
                 brace_count -= 1;
                 if brace_count == 0 {
-                // Return the byte-range of the entire JSON block
                     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(())
 }

package/prettify-log/test/fixture/expected-colored.log

@@ -0,0 +1,87 @@
+Debug: respons {
+  "some": "name",
+  "value": 12
+} is received
+{timespan} Info: some log without json
+Error: {
+  "code": 500,
+  "error": "Something went wrong"
+}
+Warning: Invalid data format detected
+{
+  "data": {
+    "id": 1,
+    "name": "test"
+  },
+  "status": "ok"
+}
+User log: {
+  "action": "login",
+  "timestamp": "2025-01-31T12:00:00Z",
+  "user": "john_doe"
+}
+Random text without json
+Debug: Payload sent: {
+  "request": {
+    "body": {
+      "key": "value"
+    },
+    "type": "POST"
+  }
+}
+Another line with no json
+{meta} Log: {"action": "update", "success": true}
+Normal message with {
+  "json": "inside"
+} text
+{
+  "array": [
+    1,
+    2,
+    3
+  ],
+  "nested": {
+    "deep": {
+      "value": "found"
+    }
+  }
+}
+{2025-01-31} Event: {"event": "created", "user": "admin"}
+Plain text that should not be modified
+Info: {
+  "details": "this is a test log",
+  "level": "info"
+}
+{
+  "array": [
+    {
+      "id": 1
+    },
+    {
+      "id": 2
+    },
+    {
+      "id": 3
+    }
+  ]
+}
+An unformatted json log {
+  "name": "example",
+  "valid": true
+}
+Debug: {
+  "data": "test",
+  "items": [
+    {
+      "x": 10,
+      "y": 20
+    }
+  ]
+}
+Non-json message with curly braces {like this}
+{
+  "key1": "value1",
+  "key2": {
+    "subkey": "subvalue"
+  }
+}

package/prettify-log/test/prettify.rs

@@ -34,3 +34,35 @@ fn test_prettify() {
         );
     }
 }
+
+#[test]
+fn test_prettify_colored() {
+    let input_file = "test/fixture/test.log";
+    let expected_output = fs::read_to_string("test/fixture/expected-colored.log")
+        .expect("Failed to read expected.log");
+
+    let mut actual_output_file = NamedTempFile::new().expect("Failed to create temp file");
+
+    let output = Command::new("cargo")
+        .args(&["run", "--quiet", "--", "--color-output"])
+        .stdin(fs::File::open(input_file).expect("Failed to open test.log"))
+        .output()
+        .expect("Failed to run prettify_logs");
+
+    assert!(output.status.success());
+
+    actual_output_file
+        .write_all(&output.stdout)
+        .expect("Failed to write output");
+
+    let actual_output = String::from_utf8_lossy(&output.stdout);
+
+    assert_eq!(actual_output.trim(), expected_output.trim(), "Output does not match expected.log");
+
+    if actual_output.trim() != expected_output.trim() {
+        eprintln!(
+            "Test failed! Actual output saved to: {}",
+            actual_output_file.path().display()
+        );
+    }
+}