Time unitsedit

Whenever durations need to be specified, eg for a timeout parameter, the duration can be specified as a whole number representing time in milliseconds, or as a time value like 2d for 2 days.

NEST uses a Time type to strongly type this and there are several ways to construct one.


The most straight forward way to construct a Time is through its constructor

var unitString = new Time("2d");
var unitComposed = new Time(2, Nest.TimeUnit.Day);
var unitTimeSpan = new Time(TimeSpan.FromDays(2));
var unitMilliseconds = new Time(1000 * 60 * 60 * 24 * 2);

When serializing Time constructed from

  • a string
  • milliseconds (as a double)
  • composition of factor and interval
  • a TimeSpan

the expression will be serialized to a time unit string composed of the factor and interval e.g. 2d


The Milliseconds property on Time is calculated even when not using the constructor that takes a double


Implicit conversionedit

There are implicit conversions from string, TimeSpan and double to an instance of Time, making them easier to work with

Time oneAndHalfYear = "1.5y";
Time fourteenDays = TimeSpan.FromDays(14);
Time twoDays = 1000*60*60*24*2;


Equality and Comparisonedit

Milliseconds are calculated even when values are not passed as double milliseconds

Time fourteenDays = TimeSpan.FromDays(14);

When dealing with years or months however, whose millsecond value cannot be calculated accurately, Milliseconds will be -1. This is because they are not fixed durations. For example

  • 30 vs. 31 vs. 28 vs. 29 days in a month
  • 365 vs. 366 days in a year
Time oneAndHalfYear = "1.5y";

This allows you to do comparisons on the expressions

Time twoDays = 1000*60*60*24*2;

(oneAndHalfYear > fourteenDays).Should().BeTrue();
(oneAndHalfYear >= fourteenDays).Should().BeTrue();
(twoDays != null).Should().BeTrue();
(twoDays >= new Time("2d")).Should().BeTrue();

(twoDays < fourteenDays).Should().BeTrue();
(twoDays <= fourteenDays).Should().BeTrue();
(twoDays <= new Time("2d")).Should().BeTrue();

And assert equality

twoDays.Should().Be(new Time("2d"));
(twoDays == new Time("2d")).Should().BeTrue();
(twoDays != new Time("2.1d")).Should().BeTrue();
(new Time("2.1d") == new Time(TimeSpan.FromDays(2.1))).Should().BeTrue();

Equality has down to 1/10 nanosecond precision

Time oneNanosecond = new Time(1, Nest.TimeUnit.Nanoseconds);
Time onePointNoughtNineNanoseconds = "1.09nanos";
Time onePointOneNanoseconds = "1.1nanos";

(oneNanosecond == onePointNoughtNineNanoseconds).Should().BeTrue();
(oneNanosecond == onePointOneNanoseconds).Should().BeFalse();

Special Time valuesedit

Elasticsearch has two special values that can sometimes be passed where a Time is accepted

  • 0 represented as Time.Zero
  • -1 represented as Time.MinusOne

The following are all equal to Time.MinusOne

new Time("-1").Should().Be(Time.MinusOne);
new Time(-1).Should().Be(Time.MinusOne);
((Time) (-1)).Should().Be(Time.MinusOne);
((Time) "-1").Should().Be(Time.MinusOne);
((Time) (-1)).Should().Be((Time) "-1");

Similarly, the following are all equal to Time.Zero

new Time("0").Should().Be(Time.Zero);
new Time(0).Should().Be(Time.Zero);
((Time) 0).Should().Be(Time.Zero);
((Time) "0").Should().Be(Time.Zero);
((Time) 0).Should().Be((Time) "0");

Special Time values 0 and -1 can be compared against other Time values although admittedly, this is a tad nonsensical.

var twoDays = new Time(2, Nest.TimeUnit.Day);

If there is a need to construct a time of -1ms or 0ms, use the constructor that accepts a factor and time unit, or specify a string with ms time units

(new Time(-1, Nest.TimeUnit.Millisecond) == new Time("-1ms")).Should().BeTrue();
(new Time(0, Nest.TimeUnit.Millisecond) == new Time("0ms")).Should().BeTrue();

Units of Timeedit

Where Units of Time can be specified as a union of either a DateInterval or Time, a DateInterval or Time may be passed which will be implicity converted to a Union<DateInterval, Time>, the serialized form of which represents the initial value passed

Expect("month").WhenSerializing<Union<DateInterval, Time>>(DateInterval.Month);
Expect("day").WhenSerializing<Union<DateInterval, Time>>(DateInterval.Day);
Expect("hour").WhenSerializing<Union<DateInterval, Time>>(DateInterval.Hour);
Expect("minute").WhenSerializing<Union<DateInterval, Time>>(DateInterval.Minute);
Expect("quarter").WhenSerializing<Union<DateInterval, Time>>(DateInterval.Quarter);
Expect("second").WhenSerializing<Union<DateInterval, Time>>(DateInterval.Second);
Expect("week").WhenSerializing<Union<DateInterval, Time>>(DateInterval.Week);
Expect("year").WhenSerializing<Union<DateInterval, Time>>(DateInterval.Year);

Expect("2d").WhenSerializing<Union<DateInterval, Time>>((Time)"2d");
Expect("11664m").WhenSerializing<Union<DateInterval, Time>>((Time)TimeSpan.FromDays(8.1));