Log Processor

A small Rust command-line program that scans a log file in parallel and prints lines containing a target keyword.

The current implementation is tuned for Linux-style system logs. By default it opens /var/log/messages, splits the file into chunks, scans those chunks across multiple threads, and reports every line containing ERROR.

Features

• Reads large log files using offset-based file reads.
• Splits work across multiple threads.
• Avoids splitting log lines in the middle of a chunk.
• Prints matching lines and a total match count.
• Uses anyhow for top-level error context.

Requirements

• Rust toolchain with Cargo.
• A Unix-like operating system.
• Read access to the configured log file.

The code currently uses std::os::unix::fs::FileExt, so it is not portable to Windows without changes.

Getting Started

Clone the repository and build it:

cargo build

Run the program:

cargo run

If /var/log/messages is not readable by your user, run against a file you can read by changing these constants in src/main.rs:

const LOG_FILE_PATH: &str = "/var/log/messages";
const TARGET_KEYWORD: &str = "ERROR";

Example Output

ERROR Lines
May 14 12:00:00 host service[123]: ERROR failed to process request
------------------------------
Log File Size (bytes): 1048576
Total occurrences of 'ERROR': 1

Development

Run the test suite:

cargo test

Check formatting:

cargo fmt --check

Run Clippy:

cargo clippy