https://github.com/tlinden/yadu
A human readable slog.Handler using YAML to show attrs
https://github.com/tlinden/yadu
color golang log log-level logger slog slog-handler structured-logging yaml
Last synced: 6 months ago
JSON representation
A human readable slog.Handler using YAML to show attrs
- Host: GitHub
- URL: https://github.com/tlinden/yadu
- Owner: TLINDEN
- License: bsd-3-clause
- Created: 2024-01-18T13:59:58.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2024-02-14T12:14:43.000Z (over 2 years ago)
- Last Synced: 2025-09-02T11:57:58.454Z (10 months ago)
- Topics: color, golang, log, log-level, logger, slog, slog-handler, structured-logging, yaml
- Language: Go
- Homepage:
- Size: 35.2 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
[](https://ci.codeberg.org/repos/15686)
[](https://goreportcard.com/report/github.com/tlinden/yadu)
[](https://codeberg.org/scip/yadu/raw/branch/main/LICENSE)
[](https://godoc.org/github.com/tlinden/yadu)
# yadu - a human readable yaml based slog.Handler
## Introduction
Package yadu provides a handler for the log/slog logging framework.
It generates a mixture of text lines containing the timestamp and
log message and a YAML dump of the provided attibutes.
## Log format
The log format generated by yadu looks like this:
```
2023-04-02T10:50.09 EDT LEVEL Message text
foo: value
bar: 12345
```
## Example
```go
logger := slog.New(yadu.NewHandler(os.Stdout, nil))
type body string
type Ammo struct {
Forweapon string
Impact int
Cost int
Range int
}
type Enemy struct {
Alive bool
Health int
Name string
Body body `yaml:"-"` // not printed
Ammo []Ammo
}
e := &Enemy{Alive: true, Health: 10, Name: "Bodo", Body: "body\nbody\n",
Ammo: []Ammo{{Forweapon: "Railgun", Range: 400, Impact: 100, Cost: 100000}},
}
slog.Info("info", "enemy", e, "spawn", 199)
```
Output:
```sh
2024-01-18T02:57.41 CET INFO: info
enemy:
alive: true
health: 10
name: Bodo
ammo:
- forweapon: Railgun
impact: 100
cost: 100000
range: 400
spawn: 199
```
See `example/example.go` for usage.
## Installation
Execute this to add the module to your project:
```sh
go get github.com/tlinden/yadu/v2
```
## Configuration
You can tweak the behavior of the handler as any other handler by using the Options struct:
```go
func removeTime(_ []string, a slog.Attr) slog.Attr {
if a.Key == slog.TimeKey {
return slog.Attr{}
}
return a
}
opts := &yadu.Options{
Level: slog.LevelDebug,
ReplaceAttr: removeTime,
}
```
Pass this object to `yadu.NewHandler()`.
Because you can pass whole structs to the logger which will be dumped
using YAML, there's also a way to exclude fields from being printed:
```go
type User struct {
Id int
User string
Pass string `yaml:"-"`
}
```
If you're already using YAML tags for other purposes you can also just
add a `LogValue()` method to your struct, which will be called by
slog. Refer to the slog documentation how to use it.
You can also modify the time format using `yadu.Options.TimeFormat`.
## Acknowledgements
I wrote most of the code with the help of the [humane slog
handler][humane]. Also helpfull was the [guide to writing `slog` handlers][guide].
+ [humane slog handler][humane]
+ [A Guide to Writing `slog` Handlers][guide]
+ [A Comprehensive Guide to Structured Logging in Go][betterstack]
[humane]: https://github.com/telemachus/humane/tree/main
[guide]: https://github.com/golang/example/tree/master/slog-handler-guide
[betterstack]: https://betterstack.com/community/guides/logging/logging-in-go/
## LICENSE
This module is published under the terms of the BSD 3-Clause
License. Please read the file LICENSE for details.
## Author
Thomas von Dein ``