https://github.com/src-d/go-log
Log is a generic logging library based on logrus
https://github.com/src-d/go-log
golang logging
Last synced: about 2 months ago
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Log is a generic logging library based on logrus
- Host: GitHub
- URL: https://github.com/src-d/go-log
- Owner: src-d
- License: apache-2.0
- Created: 2018-04-23T14:11:12.000Z (about 7 years ago)
- Default Branch: master
- Last Pushed: 2019-10-23T17:47:01.000Z (over 5 years ago)
- Last Synced: 2025-05-05T05:05:33.657Z (about 2 months ago)
- Topics: golang, logging
- Language: Go
- Homepage: https://godoc.org/gopkg.in/src-d/go-log.v1
- Size: 43 KB
- Stars: 11
- Watchers: 4
- Forks: 10
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# go-log [](https://godoc.org/github.com/src-d/go-log) [](https://travis-ci.org/src-d/go-log) [](https://ci.appveyor.com/project/mcuadros/go-log) [](https://codecov.io/github/src-d/go-log) [](https://goreportcard.com/report/github.com/src-d/go-log)
Log is a generic logging library based on logrus (this may change in the
future), that minimize the exposure of src-d projects to logrus or any other
logging library, as well defines the standard for configuration and usage of the
logging libraries in the organization.
Installation
------------
The recommended way to install *go-log* is:
```
go get -u gopkg.in/src-d/go-log.v1/...
```
Configuration
-------------
The configuration should be done always using environment variables. The list
of available variables is:
- `LOG_LEVEL`: Reporting level, values are "info", "debug", "warning" or "error".
- `LOG_FORMAT`: Format of the log lines, values are "text", "json" or "fluentd", by default "text" is used. unless a terminal can't be detected, in this case, "json" is used instead.
- `LOG_FIELDS`: Fields in JSON or fluentd format to be included in all the loggers.
- `LOG_FORCE_FORMAT`: If true the fact of being in a terminal or not is ignored.
> By default the logging is disabled if go-log is being executed in tests.
Usage
-----
### Basic usage
The most basic form of logging is made using the `Infof`, `Debugf`, `Warningf`
and `Errorf` functions at the top level of the packages.
```go
log.Infof("The answer to life, the universe and everything is %d", 42)
// INFO The answer to life, the universe and everything is 42
```
These functions use the `DefaultLogger` a logger lazy instanced when this method
are called. This logger reads the configuration from the environment variables.
### Logger instantiation
If you prefer to keep a reference to the `Logger`, in your packages or structs
to have more control over it (for example for tests). A default `Logger`, can
be instantiated using the `New` method.
```go
logger := log.New(nil)
logger.Infof("The answer to life, the universe and everything is %d", 42)
// INFO The answer to life, the universe and everything is 42
```
Also, a new `Logger` can be created from other `Logger` in order to have
contextual information, using the method `Logger.New`
```go
logger := log.New(nil)
authorLogger := logger.New(log.Field{"author": "Douglas Adams"})
bookLogger.Infof("The Hitchhiker's Guide to the Galaxy")
bookLogger.Infof("Life, the Universe and Everything")
// INFO The Hitchhiker's Guide to the Galaxy author=Douglas Adams
// INFO Life, the Universe and Everything author=Douglas Adams
```
Or if you just want to add contextual information `Logger.New` to one log line
you can use the `Logger.With` method.
```go
logger := log.New(nil)
authorLogger := logger.New(log.Field{"author": "Douglas Adams"})
bookLogger.With(log.Fields{"isbn": "0-330-25864-8"}).Infof("The Hitchhiker's Guide to the Galaxy")
bookLogger.With(log.Fields{"isbn": "0-345-39182-9"}).Infof("Life, the Universe and Everything")
// INFO The Hitchhiker's Guide to the Galaxy author=Douglas Adams isbn=0-330-25864-8
// INFO Life, the Universe and Everything author=Douglas Adams isbn=0-345-39182-9
```
### Logging errors
In `go-log` the errors are logged using the function `Logger.Errorf`:
```go
logger, _ := log.New()
_, err := http.Get("https://en.wikipedia.org/wiki/Douglas_Adams")
if err != nil {
logger.Errorf(err, "unable to retrieve page")
}
```
License
-------
Apache License Version 2.0, see [LICENSE](LICENSE)