log: improve rounding logic for log rolling directives (#3367)

* For `roll_size` and `roll_keep_for` directives, round up instead of down. For example, if a user wants to be able to look back on 36 hours of logs, but you must round to a 24-hour multiple, then it's better to round up to 48 hours (which includes the desired 36 hours) instead of down to 24 hours. * `roll_size` had an off-by-one error that caused the size to be as much as 1 MB larger than requested. For example, requests of `1MB` and `1.1MB` both became 2 MB. Now `1MB` means 1 MB, and `1.1MB` is rounded up to 2 MB.

Jeremy Lin committed May 7, 2020 at 12:06 UTC bf8c3c25c1631360133137e8e9d30ca158c6cb73

1 file changed +15 -4

modules/logging/filewriter.go

+15 -4

@@ -17,6 +17,7 @@ package logging

17 import (

18 "fmt"

19 "io"

20 + "math"

21 "os"

22 "path/filepath"

23 "strconv"

@@ -138,8 +139,15 @@ func (fw FileWriter) OpenWriter() (io.WriteCloser, error) {

139 // roll_keep_for <days>

140 // }

141 //

141 -// The roll_size value will be rounded down to number of megabytes (MiB).

142 -// The roll_keep_for duration will be rounded down to number of days.

142 +// The roll_size value has megabyte resolution.

143 +// Fractional values are rounded up to the next whole megabyte (MiB).

144 +//

145 +// The roll_keep_for duration has day resolution.

146 +// Fractional values are rounded up to the next whole number of days.

147 +//

148 +// If any of the roll_size, roll_keep, or roll_keep_for subdirectives are

149 +// omitted or set to a zero value, then Caddy's default value for that

150 +// subdirective is used.

151 func (fw *FileWriter) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {

152 for d.Next() {

153 if !d.NextArg() {

@@ -168,7 +176,7 @@ func (fw *FileWriter) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {

176 if err != nil {

177 return d.Errf("parsing size: %v", err)

178 }

171 - fw.RollSizeMB = int(size)/1024/1024 + 1

179 + fw.RollSizeMB = int(math.Ceil(float64(size) / humanize.MiByte))

180

181 case "roll_keep":

182 var keepStr string

@@ -190,7 +198,10 @@ func (fw *FileWriter) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {

198 if err != nil {

199 return d.Errf("parsing roll_keep_for duration: %v", err)

200 }

193 - fw.RollKeepDays = int(keepFor.Hours()) / 24

201 + if keepFor < 0 {

202 + return d.Errf("negative roll_keep_for duration: %v", keepFor)

203 + }

204 + fw.RollKeepDays = int(math.Ceil(keepFor.Hours() / 24))

205 }

206 }

207 }