All minutes are 60 seconds long. Leap seconds are "smeared" so that no leap
second table is needed for interpretation, using a 24-hour linear
smear.
The range is from 0001-01-01T00:00:00Z to 9999-12-31T23:59:59.999999999Z. By
restricting to that range, we ensure that we can convert to and from RFC
3339 date strings.
Examples
Example 1: Compute Timestamp from POSIX time().
Timestamp timestamp;
timestamp.set_seconds(time(NULL));
timestamp.set_nanos(0);
Example 2: Compute Timestamp from POSIX gettimeofday().
struct timeval tv;
gettimeofday(&tv, NULL);
Timestamp timestamp;
timestamp.set_seconds(tv.tv_sec);
timestamp.set_nanos(tv.tv_usec * 1000);
Example 3: Compute Timestamp from Win32 GetSystemTimeAsFileTime().
FILETIME ft;
GetSystemTimeAsFileTime(&ft);
UINT64 ticks = (((UINT64)ft.dwHighDateTime) << 32) | ft.dwLowDateTime;
A Windows tick is 100 nanoseconds. Windows epoch 1601-01-01T00:00:00Z
is 11644473600 seconds before Unix epoch 1970-01-01T00:00:00Z.
Timestamp timestamp;
timestamp.set_seconds((INT64) ((ticks / 10000000) - 11644473600LL));
timestamp.set_nanos((INT32) ((ticks % 10000000) * 100));
Example 4: Compute Timestamp from Java System.currentTimeMillis().
long millis = System.currentTimeMillis();
Timestamp timestamp = Timestamp.newBuilder().setSeconds(millis / 1000)
.setNanos((int) ((millis % 1000) * 1000000)).build();
Example 5: Compute Timestamp from Java Instant.now().
Instant now = Instant.now();
Timestamp timestamp =
Timestamp.newBuilder().setSeconds(now.getEpochSecond())
.setNanos(now.getNano()).build();
Example 6: Compute Timestamp from current time in Python.
timestamp = Timestamp()
timestamp.GetCurrentTime()
JSON Mapping
In JSON format, the Timestamp type is encoded as a string in the
RFC 3339 format. That is, the
format is "{year}-{month}-{day}T{hour}:{min}:{sec}[.{frac_sec}]Z"
where {year} is always expressed using four digits while {month}, {day},
{hour}, {min}, and {sec} are zero-padded to two digits each. The fractional
seconds, which can go up to 9 digits (i.e. up to 1 nanosecond resolution),
are optional. The "Z" suffix indicates the timezone ("UTC"); the timezone
is required. A proto3 JSON serializer should always use UTC (as indicated by
"Z") when printing the Timestamp type and a proto3 JSON parser should be
able to accept both UTC and other timezones (as indicated by an offset).
For example, "2017-01-15T01:30:15.01Z" encodes 15.01 seconds past
01:30 UTC on January 15, 2017.
In JavaScript, one can convert a Date object to this format using the
standard
toISOString()
method. In Python, a standard datetime.datetime object can be converted
to this format using
strftime with
the time format spec '%Y-%m-%dT%H:%M:%S.%fZ'. Likewise, in Java, one can use
the Joda Time's ISODateTimeFormat.dateTime() to obtain a formatter capable of generating timestamps in this format.