44 lines
1.6 KiB
TypeScript
44 lines
1.6 KiB
TypeScript
// every timestamp in this file is a number which contains an unix-timestamp-in-millisecond format,
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// like returned by `new Date().getTime()`. this is needed because the "math"
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// has to be done on integer numbers.
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// the way loki handles logs-range-queries is that if you specify start & end,
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// one of those will be included, but the other will not. this allows us to
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// make it easy to split ranges.
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// for example, if the time-range is 100<>150,
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// we can split it into:
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// - 100<>120
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// - 120<>140
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// - 140<>150
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// and no log-line will be skipped or duplicated
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// (NOTE: we do these calculations in milliseconds. at the end, Loki receives
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// nanoseconds, but it will be OK, because it's simply a matter to adding `000000`,
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// to the end, so if we do it right in milliseconds, it should be OK in
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// nanoseconds too
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export function splitTimeRange(
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startTime: number,
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endTime: number,
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idealRangeDuration: number
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): Array<[number, number]> {
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if (endTime - startTime <= idealRangeDuration) {
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return [[startTime, endTime]];
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}
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const result: Array<[number, number]> = [];
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// we walk backward, because we need want the potentially smaller "last" chunk
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// to be at the oldest timestamp.
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for (let chunkEndTime = endTime; chunkEndTime > startTime; chunkEndTime -= idealRangeDuration) {
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// when we get close to the start of the time range, we need to be sure not
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// to cross over the startTime
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const chunkStartTime = Math.max(chunkEndTime - idealRangeDuration, startTime);
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result.push([chunkStartTime, chunkEndTime]);
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}
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// because we walked backwards, we need to reverse the array
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result.reverse();
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return result;
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}
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