Rust: Custom Logger with time-stamp, file name and line number

Rust language has a built-in support for logging.  The default logger logs the log level, module name and log message which are not sufficient for troubleshooting. Fortunately,  Rust log crate does allow overriding with a custom logger.

I wanted to log the current time-stamp,  module name, function name and line number and posted a question on Reddit on how do log these information. Based on the answers, Rust does have support for module, line and file name but no support for function name. 

To implement the Custom Logger, I looked at the default logger implementation in in log crate and realized that LogRecord does support file-name and line number but while logging, it does not use it.

 pub fn log(level: u32, loc: &'static LogLocation, args: &fmt::Arguments) {  
    // Test the literal string from args against the current filter, if there  
    // is one.  
    match unsafe { FILTER.as_ref() } {  
      Some(filter) if !filter.is_match(args.to_string().as_slice()) => return,  
      _ => {}  
    // Completely remove the local logger from TLS in case anyone attempts to  
    // frob the slot while we're doing the logging. This will destroy any logger  
    // set during logging.  
    let mut logger = LOCAL_LOGGER.with(|s| {  
    }).unwrap_or_else(|| {  
      box DefaultLogger { handle: io::stderr() } as Box<Logger + Send>  
    logger.log(&LogRecord {  
      level: LogLevel(level),  
      args: args,  
      file: loc.file,  
      module_path: loc.module_path,  
      line: loc.line,  

To support the logging of function name, there is a pending RFC/Pull Request, hope that gets implemented before Rust 1.0.

For time being, let manage without function name and implement our custom logger.

 #[phase(plugin, link)]extern crate log;  
 #[phase(plugin, link)]extern crate time;  
 /// import  
 use log::{Logger,LogRecord,LogLevel,LogLocation, set_logger};  
 use std::io::{ LineBufferedWriter, stdio, stderr} ;  
 /// Custom Logger  
 struct CustomLogger {  
    handle: LineBufferedWriter<stdio::StdWriter>,  
 /// Implements Logger trait for Custom Logger which support logging timestamp, file name and line number  
 /// in addition to log level, module path and message.  
 impl Logger for CustomLogger {  
    fn log(&mut self, record: &LogRecord) {  
      match writeln!(&mut self.handle,  
             "{}:{}:{}:{}:{} {}",  
             time::strftime("%Y-%m-%d %H:%M:%S %Z", &time::now()).unwrap(),  
             record.args) {  
        Err(e) => panic!("failed to log: {}", e),  
        Ok(()) => {}  
 fn main() {  
       log::set_logger(box CustomLogger { handle: stderr() } );  
   debug!("Debug message");  
   warn!("Warn message");  
   error!("Error message");  

Here is output:
 RUST_LOG=debug ./target/custom-logger  
 2014-12-17 09:23:48 :DEBUG:custom-logger:/projects/rust/custom-logger/src/ Debug message  
 2014-12-17 09:23:48 :WARN:custom-logger:/projects/rust/custom-logger/src/ Warn message  
 2014-12-17 09:23:48 :ERROR:custom-logger:/projects/rust/custom-logger/src/ Error message  

NOTE:  I notice it doesn't print the timezone and leave an empty space.

Once I figure out the timezone issue and logging function name , it will look like below which is much better than file with being repeated.

RUST_LOG=debug ./target/custom-logger  
 2014-12-17 09:23:48 EST:DEBUG:custom-logger::main::32 Debug message  
 2014-12-17 09:23:48 EST:WARN:custom-logger::main:33 Warn message  
 2014-12-17 09:23:48 EST:ERROR:custom-logger::main:34 Error message  


karthireva said...

Thanks for sharing article like this. The way

you have stated everything above is quite

awesome. Keep blogging like this. Thanks a lot.

PHP Training in Chennai

karthireva said...

Truely a very good article on how to handle the future technology. After reading your post,thanks for taking the time to discuss this content.

Dot Net Training in Chennai ECR

Akshaysri said...

I just see the post i am so happy the post of information's.So I have really enjoyed and reading your blogs for these posts.Any way I’ll be subscribing to your feed and I hope you post again soon.
GMAT coaching chennai

Stepherd said...

Being new to the blogging world I feel like there is still so much to learn. Your tips helped to clarify a few things for me as well as giving..

Manpower Consultancy in Chennai

Sathya G said...

I have seen that all will say the same thing repeatedly. But in your blog, I had a chance to get some useful and unique information. I would like to suggest your blog in my dude circle. please keep on updates. hope it might be much useful for us. keep on updating.
SEO Training in Chennai

Thamarai Ravi said...

Thank you for sharing such a nice and interesting blog with us. I have seen that all will say the same thing repeatedly. But in your blog, I had a chance to get some useful and unique information. I would like to suggest your blog in my dude circle.
SEO Company in Chennai

amala amala said...

Finding the time and actual effort to create a superb article like this is great thing. I’ll learn many new stuff right here! Good luck for the next post buddy..
Jobs in Noida
Jobs in Pune

aashisiva said...

I must thank you for the efforts you have put in penning this site. I am hoping to check out the same high-grade content by you later on as well. In truth, your creative writing abilities has inspired me to get my own, personal blog now..
SEO Training in Chennai
Selenium Training in Chennai
Web Designing Training in Chennai

Anonymous said...

Really Good blog post.provided a helpful information.keep updating...
Digital marketing company in Chennai

mahalyasree said...

It’s the best time to make some plans for the future and it is time to be happy. I’ve read this post and if I could I want to suggest you few interesting things or suggestions.You can write next articles referring to this article. I desire to read even more things about it..
Office Interior Designers in Bangalore
Office Interior Designers in Hyderabad

Nishanth Kannan said...

Thanks for your wonderful information..
SAP Basis Training in Chennai

Tamil said...

Wonderful blog and very useful.Thanks for sharing this valuable information...
SAP Basis Training in Chennai

Search Optimization said...

Its an awesome article. written in very creative way and it also conveys useful information.

Selenium Training in Chennai

Optimizing Search said...

Its really an Excellent post. I just stumbled upon your blog and wanted to say that I have really enjoyed reading your blog. posts. I hope you post again soon.

Selenium Training in Chennai

Atom Steels said... is an online platform that allows people to find offers and the greatest deals in and around OMR. It is the directory of the business in and around omr. It helps internet users to surf the required deals and offers.

Offers in Chennai

Arushi Chaya said...

Thanks for the informative article.This is one of the best tips in my life. I have in quite some time.Nicely written and great info.I really cannot thank you enough for sharing.

Apartments in Chennai

Afiah B said...

It is amazing and wonderful to visit your site.Thanks for sharing this information,this is useful to me...
Java training in Bangalore | Java training in Jaya nagar

Java training in Bangalore | Java training in Electronic city

Java training in Chennai | Java training institute in Chennai | Java course in Chennai

Java training in USA

john jersy said...

The knowledge of technology you have been sharing thorough this post is very much helpful to develop new idea. here by i also want to share this.
python course in pune
python course in chennai
python course in Bangalore

geetha sridhar said...

This is ansuperior writing service point that doesn't always sink in within the context of the classroom. In the first superior writing service paragraph you either hook the reader's interest or lose it. Of course your teacher, who's getting paid to teach you how to write an good essay, 
Data Science training in Chennai | Data Science Training Institute in Chennai
Data science training in Bangalore | Data Science Training institute in Bangalore
Data science training in pune | Data Science training institute in Pune
Data science online training | online Data Science certification Training-Gangboard
Data Science Interview questions and answers

ais a said...

Good Post! Thank you so much for sharing this pretty post, it was so good to read and useful to improve my knowledge as updated one, keep blogging.
Best Devops training in sholinganallur
Devops training in velachery
Devops training in annanagar
Devops training in tambaram

genga g said...

Great post! I am actually getting ready to across this information, It’s very helpful for this blog.Also great with all of the valuable information you have Keep up the good work you are doing well.

angularjs Training in chennai

angularjs-Training in tambaram

angularjs-Training in sholinganallur

angularjs-Training in velachery

angularjs-Training in pune

angularjs Training in bangalore

tamilsasi said...

Inspiring writings and I greatly admired what you have to say , I hope you continue to provide new ideas for us all and greetings success always for you.
Keep update more information..

Selenium training in bangalore
Selenium training in Chennai
Selenium training in Bangalore
Selenium training in Pune
Selenium Online training
Selenium interview questions and answers

SRI said...

Read all the information that i've given in above article. It'll give u the whole idea about it.
microsoft azure training in bangalore
rpa training in bangalore
best rpa training in bangalore
rpa online training

prasadarao said...

Very nice information, it is valuable and useful to so many people. It gives the beautiful knowledge especially to the technical people.
hardware and networking course in Hyderabad
mobile repairing course in Hyderabad
laptop repairing course in Hyderabad
chip level repairing course in Hyderabad
chip level training in Hyderabad
printer repair service in Hyderabad
laptop repairing institute in hyderabad
mobile repairing institute in hyderabad
laptop repairing course
mobile repairing course
hardware and networking course
chip level repairing course
chip level training
laptop repairing in hyderabad
mobile repairing in hyderabad
laptop repairing
mobile repairing

kingdom said...

Deployment and implementation of Robotic Process Automation are the toughest tasks in the latest technology and one of the most occurred
RPA challenges as well. It affects the whole level of processes. All the processes go through different functionalities like individual and
company hierarchy. It also depends upon different companies on different levels.

BLUEPRISM RPA Training in OMR Chennai

Aaditya said...

Pretty good post. This is a wonderful article, Given so much info in it, keep sharing.

ExcelR Data Science Course in Bangalore

zaintech99 said...

I feel very grateful that I read this. It is very helpful and very informative and I really learned a lot from it.
date analytics certification training courses

Priyanka said...

Attend The Python training in bangalore From ExcelR. Practical Python training in bangalore Sessions With Assured Placement Support From Experienced Faculty. ExcelR Offers The Python training in bangalore.
python training in bangalore

Nithya Sri said...
This comment has been removed by the author.
malaysiaexcelr01 said...

I definitely enjoying every little bit of it and I have you bookmarked to check out new stuff you post.


istiaq ahmed said...

This website and I conceive this internet site is really informative ! Keep on putting up!
Data Science Course in Pune

malaysiaexcelr01 said...

I am looking for and I love to post a comment that "The content of your post is awesome" Great work!

Big Data Course

Unknown said...

I finally found great post here.I will get back here. I just added your blog to my bookmark sites. thanks.Quality posts is the crucial to invite the visitors to visit the web page, that's what this web page is science course in dubai

Unknown said...

I just got to this amazing site not long ago. I was actually captured with the piece of resources you have got here. Big thumbs up for making such wonderful blog page!data science course in dubai

zaintech99 said...

This is also a very good post which I really enjoyed reading. It is not every day that I have the possibility to see something like this..
How to Start A blog 2019

Unknown said...

I feel very grateful that I read this. It is very helpful and very informative and I Python classes in pune really learned a lot from it.

Unknown said...

I just got to this amazing site not long ago. I was actually captured with the piece of resources you have got here. Big thumbs up for making such wonderful blog page!
big data course malaysia

lucy88 said...

This is also a very good post which I really enjoyed reading. It is not every day that I have the possibility to see something like this,
Great website

technewworld said...

Really appreciate this wonderful post that you have provided for us.Great site and a great topic as well i really get amazed to read this. Its really good, Love it.

Data anlytic said...

Great Article… I love to read your articles because your writing style is too good, its is very very helpful for all of us
You will get an introduction to the Python programming language and understand the importance of it. How to download and work with Python along with all the basics of Anaconda will be taught. You will also get a clear idea of downloading the various Python libraries and how to use them.
About ExcelR Solutions and Innodatatics
Do's and Don’ts as a participant
Introduction to Python
Installation of Anaconda Python
Difference between Python2 and Python3
Python Environment
Exception Handling (Error Handling)
Excelr Solutions

Unknown said...

Excellent Blog! I would like to thank for the efforts you have made in writing this post. I am hoping the same best work from you in the future as well. I wanted to thank you for this websites! Thanks for sharing. Great websites!
big data course malaysia

datasciencecourse said...

Such a great and informative article.
You just made my day thanks for sharing this article.

data science course singapore is the best data science course

technewworld said...

Great post i must say and thanks for the information. Education is definitely a sticky subject. it is still among the leading topics of our time. I appreciate your post and looking for more.

datasciencecertification said...

I love your article so much. Good job
ExcelR is a global leader delivering a wide gamut of management and technical training over 40 countries. We are a trusted training delivery partner of 350+ corporate clients and universities across the globe with 28,000+ professionals trained across various courses. With over 20 Franchise partners all over the world, ExcelR helps individuals and organisations by providing courses based on practical knowledge and theoretical concepts.

Excelr Solutions

Unknown said...

I love your article so much. Good job
Participants who complete the assignments and projects will get the eligibility to take the online exam. Thorough preparation is required by the participants to crack the exam. ExcelR's faculty will do the necessary handholding. Mock papers and practice tests will be provided to the eligible participants which help them to successfully clear the examination.

Excelr Solutions

seoexpert said...

Nice Post...I have learn some new information.thanks for sharing.
Click here for ExcelR Business Analytics Course

Priyanka said...

Attend The Data Analytics Course in Bangalore From ExcelR. Practical Data Analytics Course in Bangalore Sessions With Assured Placement Support From Experienced Faculty. ExcelR Offers The Data Analytics Course in Bangalore.
ExcelR Data Analytics Course in Bangalore

Unknown said...

I like you article. if you you want to saw Sufiyana Pyaar Mera Star Bharat Serials Full
Sufiyana Pyaar Mera

ExcelR Pune said...

Really thanks for sharing...This blog is awesome very informative..
ExcelR Machine Learning