Port of File::RotateLogs from Perl to Go.

import (
  "net/http"

  apachelog "github.com/lestrrat/go-apache-logformat"
  rotatelogs "github.com/lestrrat/go-file-rotatelogs"
)

func main() {
  mux := http.NewServeMux()
  mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) { ... })

  logf := rotatelogs.New(
    "/path/to/access_log.%Y%m%d%H%M",
    rotatelogs.WithLinkName("/path/to/access_log"),
    rotatelogs.WithMaxAge(24 * time.Hour),
    rotatelogs.WithRotationTime(time.Hour),
  )

  http.ListenAndServe(":8080", apachelog.Wrap(mux, logf))
}

When you integrate this to to you app, it automatically write to logs that are rotated from within the app: No more disk-full alerts because you forgot to setup logrotate!

To install, simply issue a go get:

go get github.com/lestrrat/go-file-rotatelogs

It's normally expected that this library is used with some other logging service, such as the built-in log library, or loggers such as github.com/lestrrat/go-apache-logformat.

import(
  "log"
  "github.com/lestrrat/go-file-rotatelogs"
)
  
func main() {
  rl := rotatelogs.NewRotateLogs("/path/to/access_log.%Y%m%d%H%M")

  log.SetOutput(rl)

  /* elsewhere ... */
  log.Printf("Hello, World!")
}

The pattern used to generate actual log file names. You should use patterns using the strftime (3) format. For example:

  rotatelogs.New("/var/log/myapp/log.%Y%m%d")

You may specify an object that implements the roatatelogs.Clock interface. When this option is supplied, it's used to determine the current time to base all of the calculations on. For example, if you want to base your calculations in UTC, you may specify rotatelogs.UTC

  rotatelogs.New(
    "/var/log/myapp/log.%Y%m%d",
    rotatelogs.WithClock(rotatelogs.UTC),
  )

Path where a symlink for the actual log file is placed. This allows you to always check at the same location for log files even if the logs were rotated

  rotatelogs.New(
    "/var/log/myapp/log.%Y%m%d",
    rotatelogs.WithLinkName("/var/log/myapp/current"),
  )

  // Else where
  $ tail -f /var/log/myapp/current

If not provided, no link will be written.

Interval between file rotation. By default logs are rotated every 86400 seconds. Note: Remember to use time.Duration values.

  // Rotate every hour
  rotatelogs.New(
    "/var/log/myapp/log.%Y%m%d",
    rotatelogs.WithRotationTime(time.Hour),
  )

Time to wait until old logs are purged. By default no logs are purged, which certainly isn't what you want. Note: Remember to use time.Duration values.

  // Purge logs older than 1 hour
  rotatelogs.New(
    "/var/log/myapp/log.%Y%m%d",
    rotatelogs.WithMaxAge(time.Hour),
  )