/
logger.go
62 lines (55 loc) · 1.8 KB
/
logger.go
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package llog
import (
"io"
"log"
"strings"
)
type llogWriter struct {
fn LogFunc
kv KV
filters []func(string) (string, error)
}
// Write implements the io.Writer interface
func (lw *llogWriter) Write(b []byte) (int, error) {
msg := strings.TrimSpace(string(b))
for _, fn := range lw.filters {
m, err := fn(msg)
if err != nil {
return 0, err
}
// ignore if there's no message left
if m == "" {
// pretend we still wrote everything
return len(b), nil
}
msg = m
}
// TODO: what should we do with multi-line messages
lw.fn(msg, lw.kv)
return len(b), nil
}
// NewLogger returns an instance of log.Logger that uses llog to log the
// messages under the sent level with the passed KV. Multiple filter functions
// can be passed. If an error is returned from the filter function, it's sent
// to the caller of the Write method. If an empty string is returned then the
// message is ignored.
func NewLogger(lvl Level, kv KV, filters ...func(string) (string, error)) *log.Logger {
return newErrorLogger(logFuncFromLevel(lvl), kv, filters)
}
func newErrorLogger(fn LogFunc, kv KV, filters []func(string) (string, error)) *log.Logger {
return log.New(newWriter(fn, kv, filters...), "", 0)
}
// NewWriter returns an io.Writer that uses llog to log the sent writes with the
// sent log level. Multiple filter functions can be passed. If an error is
// returned from the filter function, it's sent to the caller of the Write
// method. If an empty string is returned then the message is ignored.
func NewWriter(lvl Level, kv KV, filters ...func(string) (string, error)) io.Writer {
return newWriter(logFuncFromLevel(lvl), kv, filters...)
}
func newWriter(fn LogFunc, kv KV, filters ...func(string) (string, error)) io.Writer {
return &llogWriter{
fn: fn,
kv: kv,
filters: filters,
}
}