co-log-core: Composable Contravariant Comonadic Logging Library

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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:

co-log: Composable Contravariant Combinatorial Comonadic Configurable Convenient Logging

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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Properties

Versions	0.0.0, 0.1.0, 0.1.1, 0.2.0.0, 0.2.1.0, 0.2.1.1, 0.2.1.1, 0.3.0.0, 0.3.1.0, 0.3.2.0, 0.3.2.1, 0.3.2.2
Change log	CHANGELOG.md
Dependencies	base (>=4.10.1.0 && <4.15) [details]
License	MPL-2.0
Copyright	2018-2020 Kowainik
Author	Dmitrii Kovanikov
Maintainer	Kowainik <xrom.xkov@gmail.com>
Category	Logging, Contravariant, Comonad
Home page	https://github.com/kowainik/co-log
Bug tracker	https://github.com/kowainik/co-log/issues
Source repo	head: git clone https://github.com/kowainik/co-log.git
Uploaded	by shersh at 2020-04-18T20:11:39Z

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Colog
- Colog.Core

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co-log-core-0.2.1.1.tar.gz [browse] (Cabal source package)
Package description (as included in the package)

Maintainer's Corner

Package maintainers

vrom911, alaendle

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Readme for co-log-core-0.2.1.1

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co-log


`co-log-core`
`co-log`
`co-log-polysemy`

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: Composable Contravariant Combinatorial Comonadic Configurable Convenient Logging

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:

tutorials/Concurrent.hs

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`