co-log-core: Composable Contravariant Comonadic Logging Library

[ comonad, contravariant, library, logging, mpl ] [ Propose Tags ]

This package provides core types and functions to work with the LogAction data type which is both simple and powerful.

newtype LogAction m msg = LogAction
    { unLogAction :: msg -> m ()
    }

The ideas behind this package are described in the following blog post:

See the following packages for different implementations based on co-log-core:

  • co-log: taggless final implementations.

  • co-log-polysemy: extensible effects implementation based on polysemy.


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Versions [RSS] 0.0.0, 0.1.0, 0.1.1, 0.2.0.0, 0.2.1.0, 0.2.1.1, 0.3.0.0, 0.3.1.0
Change log CHANGELOG.md
Dependencies base (>=4.10.1.0 && <4.16) [details]
License MPL-2.0
Copyright 2018-2020 Kowainik, 2021 Co-Log
Author Dmitrii Kovanikov
Maintainer Kowainik <xrom.xkov@gmail.com>
Category Logging, Contravariant, Comonad
Home page https://github.com/co-log/co-log-core
Bug tracker https://github.com/co-log/co-log-core/issues
Source repo head: git clone https://github.com/co-log/co-log-core.git
Uploaded by shersh at 2021-10-29T02:56:34Z
Distributions NixOS:0.3.1.0
Downloads 4974 total (132 in the last 30 days)
Rating 2.25 (votes: 2) [estimated by Bayesian average]
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Readme for co-log-core-0.3.0.0

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co-log

Co-logo

GitHub CI Build status Windows build MPL-2.0 license

co-log-core Hackage Stackage LTS Stackage Nightly
co-log Hackage Stackage LTS Stackage Nightly
co-log-polysemy Hackage Stackage LTS Stackage Nightly

co-log is a composable and configurable logging framework. It combines all the benefits of Haskell idioms to provide a reasonable and convenient interface. Though it uses some advanced concepts in its core, we are striving to provide beginner-friendly API. The library also contains complete documentation with a lot of beginner-friendly examples, explanations and tutorials to guide users. The combination of a pragmatic approach to logging and fundamental Haskell abstractions allows us to create a highly composable and configurable logging framework.

If you're interested in how different Haskell typeclasses are used to implement core functions of co-log, you can read the following blog post which goes into detail about internal implementation specifics:

co-log is also modular on the level of packages. We care a lot about a low dependency footprint so you can build your logging only on top of the minimal required interface for your use-case. This repository contains the following packages:

  • co-log-core: lightweight package with basic data types and general idea which depends only on base.
  • co-log: taggless final implementation of logging library based on co-log-core.
  • co-log-polysemy: implementation of logging library based on co-log-core and the polysemy extensible effects library.
  • co-log-benchmark: benchmarks of the co-log library.

To provide a more user-friendly introduction to the library, we've created the tutorial series which introduces the main concepts behind co-log smoothly:

co-log also cares about concurrent logging. For this purpose we have the concurrent-playground executable where we experiment with different multithreading scenarios to test the library's behavior. You can find it here:

Benchmarks

co-log is compared with basic functions like putStrLn. Since IO overhead is big enough, every benchmark dumps 10K messages to output. If a benchmark's name doesn't contain Message then this benchmark simply dumps the string "message" to output, otherwise it works with the Message data type from the co-log library.

To run benchmarks, use the following command:

cabal v2-run co-log-bench
Benchmarks Time for 10K messages
Prelude.putStrLn 5.117ms
Text.putStrLn 9.220ms
ByteString.putStrLn 2.971ms
mempty 1.181ms
logStringStdout 5.107ms
logPrint 5.248ms
logTextStdout 5.351ms
logByteStringStdout 2.933ms
logByteStringStderr 17.482ms
ByteString > (stdout <> stderr) 17.715ms
Message > format > stdout 9.188ms
Message > format > ByteString > stdout 3.524ms
Message{callstack} > format > stdout 9.139ms
Message{callstack:5} > format > stdout 9.464ms
Message{callstack:50} > format > stdout 9.439ms
Message{Time,ThreadId} > format > stdout 54.160ms
Message{Time,ThreadId} > format > ByteString > stdout 54.137ms