If you use Logtail to collect logs, you must specify time formats based on the time strings in raw logs. Logtail extracts a time string from a raw log and parses the string into a UNIX timestamp. This topic describes the time formats that are commonly used in logs and provides examples of the time formats.
Commonly used time formats in logs
The following table describes the time formats that are supported by Logtail.
By default, the timestamp of a log in Simple Log Service is accurate to the second. You need to only specify a time format that is accurate to the second.
If the value of the time field in raw logs has a higher time precision, such as the millisecond, microsecond, or nanosecond, and you want to retain the time precision for the logs in Simple Log Service, see Extract timestamps that are accurate to the nanosecond from logs that are collected by using Logtail.
You need to only specify a time format for the time part in a time string. You do not need to specify a time format for other parts such as a time zone.
If Logtail is installed on a Linux server, Logtail supports all time formats that are supported by the strftime function. If the time string in a log can be formatted by the strftime function, the time string can be parsed and used by Logtail.
Time format | Description | Example |
%a | The abbreviated name of the day of the week. | Fri |
%A | The full name of the day of the week. | Friday |
%b | The abbreviated name of the month. | Jan |
%B | The full name of the month. | January |
%d | The day of the month. The value is in the decimal format. Valid values: 01 to 31. | 07, 31 |
%f | The decimal part of the second, including the millisecond, microsecond, and nanosecond. | 123 |
%h | The abbreviated name of the month. The format is equivalent to %b. | Jan |
%H | The hour. The 24-hour clock is used. | 22 |
%I | The hour. The 12-hour clock is used. | 11 |
%m | The month. The value is in the decimal format. Valid values: 01 to 12. | 08 |
%M | The minute. The value is in the decimal format. Valid values: 00 to 59. | 59 |
%n | The line feed. | Line feed |
%p | The abbreviation that indicates the morning or afternoon. Valid values: AM and PM. | AM or PM |
%r | The time. The 12-hour clock is used. The format is equivalent to %I:%M:%S %p. | 11:59:59 AM |
%R | The time. Hours and minutes are included. The format is equivalent to %H:%M. | 23:59 |
%S | The second. The value is in the decimal format. Valid values: 00 to 59. | 59 |
%t | The tab character. | None |
%y | The two-digit number of the year. The value is in the decimal format. Valid values: 00 to 99. | 04 or 98 |
%Y | The four-digit number of the year. The value is in the decimal format. | 2004 or 1998 |
%C | The two-digit number of the century. The value is in the decimal format. Valid values: 00 to 99. | 16 |
%e | The day of the month. The value is in the decimal format. Valid values: 1 to 31. Prefix a single-digit number with a space. | 7 or 31 |
%j | The day of the year. The value is in the decimal format. Valid values: 001 to 366. | 365 |
%u | The day of the week. The value is in the decimal format. Valid values: 1 to 7. The value 1 indicates Monday. | 2 |
%U | The week of the year. Sunday is the first day of each week. Valid values: 00 to 53. | 23 |
%V | The week of the year. Monday is the first day of each week. Valid values: 01 to 53. If a week on which January 1 falls has four or more days in January, the week is considered the first week of the year. Otherwise, the following week is considered the first week of the year. | 24 |
%w | The day of the week. The value is in the decimal format. Valid values: 0 to 6. The value 0 indicates Sunday. | 5 |
%W | The week of the year. Monday is the first day of each week. Valid values: 00 to 53. | 23 |
%c | The date and time that follows the ISO 8601 standard. | Tue Nov 20 14:12:58 2020 |
%x | The date that follows the ISO 8601 standard. | 08/19/2020 |
%X | The time that follows the ISO 8601 standard. | 11:59:59 |
%s | The UNIX timestamp. | 1476187251 |
Examples
The following table describes common time standards and time expressions, and provides corresponding examples.
Example | Time expression | Time standard |
2017-12-11 15:05:07 | %Y-%m-%d %H:%M:%S | Custom |
2017-12-11 15:05:07.123 | %Y-%m-%d %H:%M:%S.%f | Custom |
[2017-12-11 15:05:07.012] | [%Y-%m-%d %H:%M:%S] | Custom |
02 Jan 06 15:04 MST | %d %b %y %H:%M | RFC822 |
02 Jan 06 15:04 -0700 | %d %b %y %H:%M | RFC822Z |
Monday, 02-Jan-06 15:04:05 MST | %A, %d-%b-%y %H:%M:%S | RFC850 |
Mon, 02 Jan 2006 15:04:05 MST | %A, %d %b %Y %H:%M:%S | RFC1123 |
2006-01-02T15:04:05Z07:00 | %Y-%m-%dT%H:%M:%S | RFC3339 |
2006-01-02T15:04:05.999999999Z07:00 | %Y-%m-%dT%H:%M:%S | RFC3339Nano |
1637843406 | %s | Custom |
1637843406123 | %s | Custom (Simple Log Service considers second as the precision of the time.) |