https://github.com/ipfs/go-log
A logging library used by go-ipfs
https://github.com/ipfs/go-log
Last synced: about 1 year ago
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A logging library used by go-ipfs
- Host: GitHub
- URL: https://github.com/ipfs/go-log
- Owner: ipfs
- License: mit
- Created: 2015-09-15T00:04:46.000Z (over 10 years ago)
- Default Branch: master
- Last Pushed: 2025-03-29T08:32:14.000Z (about 1 year ago)
- Last Synced: 2025-04-14T00:59:39.954Z (about 1 year ago)
- Language: Go
- Homepage:
- Size: 400 KB
- Stars: 62
- Watchers: 23
- Forks: 49
- Open Issues: 13
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# go-log
[](https://protocol.ai)
[](https://ipfs.io/)
[](https://pkg.go.dev/github.com/ipfs/go-log/v2)
> The logging library used by go-ipfs
go-log wraps [zap](https://github.com/uber-go/zap) to provide a logging facade. go-log manages logging
instances and allows for their levels to be controlled individually.
## Install
```sh
go get github.com/ipfs/go-log
```
## Usage
Once the package is imported under the name `logging`, an instance of `EventLogger` can be created like so:
```go
var log = logging.Logger("subsystem name")
```
It can then be used to emit log messages in plain printf-style messages at seven standard levels:
Levels may be set for all loggers:
```go
lvl, err := logging.LevelFromString("error")
if err != nil {
panic(err)
}
logging.SetAllLoggers(lvl)
```
or individually:
```go
err := logging.SetLogLevel("net:pubsub", "info")
if err != nil {
panic(err)
}
```
or by regular expression:
```go
err := logging.SetLogLevelRegex("net:.*", "info")
if err != nil {
panic(err)
}
```
### Environment Variables
This package can be configured through various environment variables.
#### `GOLOG_LOG_LEVEL`
Specifies the log-level, both globally and on a per-subsystem basis.
For example, the following will set the global minimum log level to `error`, but reduce the minimum
log level for `subsystem1` to `info` and reduce the minimum log level for `subsystem2` to debug.
```bash
export GOLOG_LOG_LEVEL="error,subsystem1=info,subsystem2=debug"
```
`IPFS_LOGGING` is a deprecated alias for this environment variable.
#### `GOLOG_FILE`
Specifies that logs should be written to the specified file. If this option is _not_ specified, logs are written to standard error.
```bash
export GOLOG_FILE="/path/to/my/file.log"
```
#### `GOLOG_OUTPUT`
Specifies where logging output should be written. Can take one or more of the following values, combined with `+`:
- `stdout` -- write logs to standard out.
- `stderr` -- write logs to standard error.
- `file` -- write logs to the file specified by `GOLOG_FILE`
For example, if you want to log to both a file and standard error:
```bash
export GOLOG_FILE="/path/to/my/file.log"
export GOLOG_OUTPUT="stderr+file"
```
Setting _only_ `GOLOG_FILE` will prevent logs from being written to standard error.
#### `GOLOG_LOG_FMT`
Specifies the log message format. It supports the following values:
- `color` -- human readable, colorized (ANSI) output
- `nocolor` -- human readable, plain-text output.
- `json` -- structured JSON.
For example, to log structured JSON (for easier parsing):
```bash
export GOLOG_LOG_FMT="json"
```
The logging format defaults to `color` when the output is a terminal, and `nocolor` otherwise.
`IPFS_LOGGING_FMT` is a deprecated alias for this environment variable.
#### `GOLOG_LOG_LABELS`
Specifies a set of labels that should be added to all log messages as comma-separated key-value
pairs. For example, the following add `{"app": "example_app", "dc": "sjc-1"}` to every log entry.
```bash
export GOLOG_LOG_LABELS="app=example_app,dc=sjc-1"
```
## Contribute
Feel free to join in. All welcome. Open an [issue](https://github.com/ipfs/go-log/issues)!
This repository falls under the IPFS [Code of Conduct](https://github.com/ipfs/community/blob/master/code-of-conduct.md).
### Want to hack on IPFS?
[](https://github.com/ipfs/community/blob/master/CONTRIBUTING.md)
## License
MIT