Caution
This project has been archived. Successor project: kunitsucom/ilog.go
rec.go is a lightweight and no dependencies simple JSON (NDJSON, JSONLines, JSONL) logger for Go.
To provide a JSON logger with a simple interface, easy setup, and no dependencies.
- Simple and easy-to-use interface
- Anyone can start using rec.go by just reading the README for a minute.
- Lightweight
- Benchmark comparison rec.go with major logger libraries.
- excerpt:
Output of log entries with common JSON log format and 1
errorfield:logger time/op delta rec.go 2.25µs ± 7% - zap 8.24µs ±10% +266.51% zerolog 7.76µs ± 6% +245.24% logger alloc/op bytes delta rec.go 208B ± 0% - zap 392B ± 0% +88.65% zerolog 336B ± 0% +61.54% logger allocs/op times delta rec.go 1.00 ± 0% - zap 4.00 ± 0% +300.00% zerolog 4.00 ± 0% +300.00%
- excerpt:
- Benchmark comparison rec.go with major logger libraries.
- No dependencies
- Take a look at this clean
go.mod. - rec.go will never corrupt your
go.modandgo.sum.
- Take a look at this clean
Use default logger (go.dev/play)
package main
import (
"io"
"os"
"time"
"golang.org/x/xerrors"
"github.com/kunitsuinc/rec.go"
)
func main() {
t := time.Minute
err := xerrors.Errorf("error: %w", io.EOF)
wrap := xerrors.Errorf("wrap: %w", err)
// Use default logger
rec.L().Info(
"default logger",
rec.DurationFormat("duration", t),
rec.Error(wrap),
rec.ErrorStacktrace(wrap),
)
}output:
$ go run main.go
{"timestamp":"2009-11-10T23:00:00Z","severity":"INFO","caller":"sandbox1448316521/prog.go:17","message":"default logger","duration":"1m0s","error":"wrap: error: EOF","errorStacktrace":"wrap:\n main.main\n /tmp/sandbox1448316521/prog.go:15\n - error:\n main.main\n /tmp/sandbox1448316521/prog.go:14\n - EOF"}Setup logger using default config (go.dev/play)
package main
import (
"io"
"os"
"time"
"golang.org/x/xerrors"
"github.com/kunitsuinc/rec.go"
)
func main() {
// Setup logger using default config
logger := rec.Must(rec.New(os.Stderr))
t := time.Minute
err := xerrors.Errorf("error: %w", io.EOF)
wrap := xerrors.Errorf("wrap: %w", err)
logger.Info(
"logger generated from default config",
rec.DurationFormat("duration", t),
rec.Error(wrap),
rec.ErrorStacktrace(wrap),
)
}output:
$ go run main.go
{"timestamp":"2009-11-10T23:00:00Z","severity":"INFO","caller":"sandbox1333751707/prog.go:20","message":"logger generated from default config","duration":"1m0s","error":"wrap: error: EOF","errorStacktrace":"wrap:\n main.main\n /tmp/sandbox1333751707/prog.go:18\n - error:\n main.main\n /tmp/sandbox1333751707/prog.go:17\n - EOF"}Setup logger using rec.Option (go.dev/play)
package main
import (
"io"
"os"
"time"
"golang.org/x/xerrors"
"github.com/kunitsuinc/rec.go"
)
func main() {
// Setup logger using rec.Option (Functional options)
logger := rec.Must(rec.New(os.Stderr, rec.WithTimestampFieldKey("time"), rec.WithUseHostnameField(true), rec.WithHostnameFieldKey("host")))
t := time.Minute
err := xerrors.Errorf("error: %w", io.EOF)
wrap := xerrors.Errorf("wrap: %w", err)
logger.Info(
"logger generated from rec.Option",
rec.DurationFormat("duration", t),
rec.Error(wrap),
rec.ErrorStacktrace(wrap),
)
}output:
$ go run main.go
{"time":"2009-11-10T23:00:00Z","severity":"INFO","host":"f054dfbe1788","caller":"sandbox480936273/prog.go:20","message":"logger generated from rec.Option","duration":"1m0s","error":"wrap: error: EOF","errorStacktrace":"wrap:\n main.main\n /tmp/sandbox480936273/prog.go:18\n - error:\n main.main\n /tmp/sandbox480936273/prog.go:17\n - EOF"}Setup logger using rec.Config (go.dev/play)
package main
import (
"io"
"os"
"time"
"golang.org/x/xerrors"
"github.com/kunitsuinc/rec.go"
)
func main() {
config := &rec.Config{
// "timestamp":"...",
UseTimestampField: true,
TimestampFieldKey: "timestamp",
TimestampFieldFormat: time.RFC3339Nano,
// "severity":"...",
UseSeverityField: true,
SeverityFieldKey: "severity",
SeverityThreshold: rec.DEFAULT,
UseUppercaseSeverity: true,
// "hostname":"...",
UseHostnameField: true,
HostnameFieldKey: "hostname",
HostnameFieldValue: os.Getenv("HOSTNAME"),
// "caller":"...",
UseCallerField: true,
CallerFieldKey: "caller",
CallerSkip: 4,
UseShortCaller: true,
// "message":"...",
UseMessageField: true,
MessageFieldKey: "message",
// \n
LineSeparator: "\n",
}
// Setup logger using rec.Config
logger := rec.Must(rec.NewWithConfig(os.Stderr, config))
t := time.Minute
err := xerrors.Errorf("error: %w", io.EOF)
wrap := xerrors.Errorf("wrap: %w", err)
logger.Info(
"logger generated from rec.Config",
rec.DurationFormat("duration", t),
rec.Error(wrap),
rec.ErrorStacktrace(wrap),
)
}output:
$ go run main.go
{"timestamp":"2009-11-10T23:00:00Z","severity":"INFO","hostname":"acab9130628a","caller":"sandbox2890955676/prog.go:46","message":"logger generated from rec.Config","duration":"1m0s","error":"wrap: error: EOF","errorStacktrace":"wrap:\n main.main\n /tmp/sandbox2890955676/prog.go:44\n - error:\n main.main\n /tmp/sandbox2890955676/prog.go:43\n - EOF"}Setup buffered logger (go.dev/play)
package main
import (
"bufio"
"io"
"os"
"time"
"golang.org/x/xerrors"
"github.com/kunitsuinc/rec.go"
)
func main() {
// new *bufio.Writer
bufStderr := bufio.NewWriter(os.Stderr)
defer bufStderr.Flush()
// Setup buffered logger
logger := rec.Must(rec.New(bufStderr))
t := time.Minute
err := xerrors.Errorf("error: %w", io.EOF)
wrap := xerrors.Errorf("wrap: %w", err)
logger.Info(
"buffered logger",
rec.DurationFormat("duration", t),
rec.Error(wrap),
rec.ErrorStacktrace(wrap),
)
}output:
$ go run main.go
{"timestamp":"2009-11-10T23:00:00Z","severity":"INFO","caller":"sandbox499319467/prog.go:26","message":"buffered logger","duration":"1m0s","error":"wrap: error: EOF","errorStacktrace":"wrap:\n main.main\n /tmp/sandbox499319467/prog.go:24\n - error:\n main.main\n /tmp/sandbox499319467/prog.go:23\n - EOF"}Setup logger that context fields added (go.dev/play)
package main
import (
"bufio"
"io"
"os"
"time"
"golang.org/x/xerrors"
"github.com/kunitsuinc/rec.go"
)
func main() {
// new *bufio.Writer
bufStderr := bufio.NewWriter(os.Stderr)
defer bufStderr.Flush()
// Setup buffered logger
logger := rec.Must(rec.New(bufStderr))
contextLogger := logger.With(rec.String("name", "myLogger"), rec.Int("id", 100))
t := time.Minute
err := xerrors.Errorf("error: %w", io.EOF)
wrap := xerrors.Errorf("wrap: %w", err)
contextLogger.Info(
"buffered logger",
rec.DurationFormat("duration", t),
rec.Error(wrap),
rec.ErrorStacktrace(wrap),
)
}output:
$ go run main.go
{"timestamp":"2009-11-10T23:00:00Z","severity":"INFO","caller":"sandbox1328679084/prog.go:27","message":"buffered logger","name":"myLogger","id":100,"duration":"1m0s","error":"wrap: error: EOF","errorStacktrace":"wrap:\n main.main\n /tmp/sandbox1328679084/prog.go:25\n - error:\n main.main\n /tmp/sandbox1328679084/prog.go:24\n - EOF"}Replace the logger in the Go standard log package with rec.Logger, and rollback (go.dev/play)
package main
import (
"log"
"os"
"github.com/kunitsuinc/rec.go"
)
func main() {
logger := rec.Must(rec.New(os.Stderr))
// Replace the logger in the Go standard log package with rec.Logger
rollback := rec.ReplaceStdLogger(logger, rec.INFO)
log.Println("replaced")
// To revert back to the original logger, run rollback.
rollback()
log.Println("rollback")
}output:
$ go run main.go
{"timestamp":"2009-11-10T23:00:00Z","severity":"INFO","caller":"sandbox1964866315/prog.go:16","message":"replaced"}
2009/11/10 23:00:00 rollback