[chrono-systemd-time] is a library which parses timestamps following the [systemd.time] specifications into [chrono] types.
Put this in your Cargo.toml:
toml
[dependencies]
chrono-systemd-time = "0.1"
The supported timestamp formats are any defined by the systemd.time specifications, with a few exceptions: * time units must accompany all time span values. * time zone suffixes are not supported. * weekday prefixes are not supported.
The format of a timestamp may be either a time, a time span, or a combination of a time +/- a time span. * When only a time is given, the parsed time is returned. * When only a time span is given, the time span is added or subtracted from the current time (now). * When a combination of a time and a time span is given, the time span is added or subtracted from the parsed time.
Examples of parsing valid timestamps, assuming now is 2018-06-21 01:02:03: ```rust,ignore parsetimestamptz("2018-08-20 09:11:12.123", Utc) == "2018-08-20T09:11:12.000123Z" parsetimestamptz("2018-08-20 09:11:12", Utc) == "2018-08-20T09:11:12Z" parsetimestamptz("18-08-20 09:11:12 +2m", Utc) == "2018-08-20T09:13:12Z" parsetimestamptz("2018-08-20 + 1h2m3s", Utc) == "2018-08-20T01:02:03Z" parsetimestamptz("18-08-20 - 1h 2m 3s", Utc) == "2018-08-19T22:57:57Z" parsetimestamptz("09:11:12 -1day", Utc) == "2018-06-20T09:11:12Z" parsetimestamptz("09:11:12.123", Utc) == "2018-06-21T09:11:12.000123Z" parsetimestamptz("11:12", Utc) == "2018-06-21T11:12:00Z" parsetimestamptz("now", Utc) == "2018-06-21T01:02:03.203918151Z" parsetimestamptz("today", Utc) == "2018-06-21T00:00:00Z" parsetimestamptz("yesterday -2days", Utc) == "2018-06-18T00:00:00Z" parsetimestamptz("tomorrow +1week", Utc) == "2018-06-29T00:00:00Z"
parse_timestamp_tz("epoch +1529578800s", Utc) == "2018-06-21T11:00:00Z"
parse_timestamp_tz("@1529578800s", Utc) == "2018-06-21T11:00:00Z"
parse_timestamp_tz("now +4h50m", Utc) == "2018-06-21T05:52:03.203918151Z"
parse_timestamp_tz("4h50m left", Utc) == "2018-06-21T05:52:03.203918151Z"
parse_timestamp_tz("+4h50m", Utc) == "2018-06-21T05:52:03.203918151Z"
parse_timestamp_tz("now -3s", Utc) == "2018-06-21T01:02:00.203918151Z"
parse_timestamp_tz("3s ago", Utc) == "2018-06-21T01:02:00.203918151Z"
parse_timestamp_tz("-3s", Utc) == "2018-06-21T01:02:00.203918151Z"
```
The syntax of a time consists of a set of keywords and strftime formats:
* "now", "epoch"
* "today", "yesterday", "tomorrow"
* "%y-%m-%d %H:%M:%S", "%Y-%m-%d %H:%M:%S"
* "%y-%m-%d %H:%M", "%Y-%m-%d %H:%M"
* "%y-%m-%d", "%Y-%m-%d"
* "%H:%M:%S"
* "%H:%M"
Strftime timestamps with a seconds component may also include a microsecond component, separated by a '.'.
* When the date is omitted, today is assumed.
* When the time is omitted, 00:00:00 is assumed.
Examples of valid times (assuming now is 2018-06-21 01:02:03):
rust,ignore
    "2018-08-20 09:11:12.123" == "2018-08-20T09:11:12.000123"
        "2018-08-20 09:11:12" == "2018-08-20T09:11:12"
          "18-08-20 09:11:12" == "2018-08-20T09:11:12"
                 "2018-08-20" == "2018-08-20T00:00:00"
                   "18-08-20" == "2018-08-20T00:00:00"
                   "09:11:12" == "2018-06-21T09:11:12"
               "09:11:12.123" == "2018-06-21T09:11:12.000123"
                      "11:12" == "2018-06-21T11:12:00"
                        "now" == "2018-06-21T01:02:03.203918151"
                      "epoch" == "1970-01-01T00:00:00"
                      "today" == "2018-06-21T00:00:00"
                  "yesterday" == "2018-06-20T00:00:00"
                   "tomorrow" == "2018-06-22T00:00:00"
A time span is made up of a combination of time units, with the following time units understood:
* "usec", "us", "µs"
* "msec", "ms"
* "seconds", "second", "sec", "s"
* "minutes", "minute", "min", "m"
* "hours", "hour", "hr", "h"
* "days", "day", "d"
* "weeks", "week", "w"
* "months", "month", "M" (defined as 30.44 days)
* "years", "year", "y" (defined as 365.25 days)
All components of a time span are added together.
Examples of valid time spans:
rust,ignore
          "3hours" == Duration::hours(3)
           "2d 5h" == Duration::days(2) + Duration::hours(5)
    "1y 10 months" == Duration::years(1) + Duration::months(10)
          "30m22s" == Duration::minutes(30) + Duration::seconds(22)
       "10m 2s 5m" == Duration::minutes(15) + Duration::seconds(2)
        "10d 2 5m" == Duration::days(10) + Duration::minutes(25)