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K6
lib
NewExecutionSegmentSequenceWrapper

How to use NewExecutionSegmentSequenceWrapper method of lib Package

Best K6 code snippet using lib.NewExecutionSegmentSequenceWrapper

execution_segment.go

Source:execution_segment.go

...440	// The striped offsets, i.e. the repeating indexes that "belong" to each441	// execution segment in the sequence.442	offsets [][]int64443}444// NewExecutionSegmentSequenceWrapper expects a filled-out execution segment445// sequence. It pre-calculates the initial caches of and returns a new446// ExecutionSegmentSequenceWrapper, but doesn't calculate the striped offsets.447func NewExecutionSegmentSequenceWrapper(ess ExecutionSegmentSequence) *ExecutionSegmentSequenceWrapper {448	if !ess.IsFull() {449		panic(fmt.Sprintf("Cannot wrap around a non-full execution segment sequence '%s'", ess))450	}451	sequenceLength := len(ess)452	offsets := make([][]int64, sequenceLength)453	lcd := ess.LCD()454	// This will contain the normalized numerator values (i.e. what they would have455	// been if all denominators were equal to the LCD), sorted in descending456	// order (i.e. biggest segments are first), with references to their actual457	// indexes in the execution segment sequence (i.e. `seq` above).458	sortedNormalizedIndexes := make([]struct {459		normNumerator int64460		originalIndex int461	}, sequenceLength)462	for i := range ess {463		normalizedNumerator := ess[i].length.Num().Int64() * (lcd / ess[i].length.Denom().Int64())464		sortedNormalizedIndexes[i].normNumerator = normalizedNumerator465		sortedNormalizedIndexes[i].originalIndex = i466		offsets[i] = make([]int64, 0, normalizedNumerator+1)467	}468	sort.SliceStable(sortedNormalizedIndexes, func(i, j int) bool {469		return sortedNormalizedIndexes[i].normNumerator > sortedNormalizedIndexes[j].normNumerator470	})471	// This is the striping algorithm. Imagine you have a number of rational472	// numbers which all add up to 1 (or less), and call them segments. If you473	// want each to get proportional amount of anything, you need to give them474	// their numerator count of elements for each denominator amount from the475	// original elements. So, for 1/3, you give 1 element for each 3 elements.476	// For 3/5 - 3 elements for each 5. If you have, for example, a sequence477	// with elements with length 3/5 and 1/3, in order to know how to distribute478	// it accurately, you need to get the LCD(lowest common denominitor). In479	// this case, between 3 and 5, the LCD is 15. Then to transform the numbers480	// to have the same, LCD equal, denominator. So 3/5 becomes 9/15 and 1/3481	// becomes 5/15. So now for each 15 elements 9 need to go to the 3/5, and 5482	// need to go to 1/3. This is what we did above in sortedNormalizedIndexes.483	//484	// We use the algorithm below to split elements between ExecutionSegments by485	// using their length as the rational number. As we would like to get486	// non-sequential elements, we try to get the maximum distance between them.487	// That is the number of elements divided by the number of elements for any488	// given segment, which concidently is the length of the segment reversed.489	// The algorithm below does the following:490	//  1. Goes through the elements from 0 to the lcd-1491	//  2. For each of element, it goes through the segments and looks if the492	//     amount of already taken elements by the given segment, multiplied by493	//     that segment's length inverted, is equal to or less to the current494	//     element index. If it is, give that element to that segment. If not,495	//     continue with the next element.496	// The code below specifically avoids using big.Rat, for performance497	// reasons, which complicates the code somewhat. As additional note, the498	// sorting of the segments from biggest to smallest helps with the fact that499	// the biggest elements will need to take the most elements, and for them it500	// will be the hardest to not get sequential elements.501	prev := make([]int64, sequenceLength)502	chosenCounts := make([]int64, sequenceLength)503	saveIndex := func(iteration int64, index int, numerator int64) {504		offsets[index] = append(offsets[index], iteration-prev[index])505		prev[index] = iteration506		if int64(len(offsets[index])) == numerator {507			offsets[index] = append(offsets[index], offsets[index][0]+lcd-iteration)508		}509	}510	for i := int64(0); i < lcd; i++ {511		for sortedIndex, chosenCount := range chosenCounts {512			num := chosenCount * lcd513			denom := sortedNormalizedIndexes[sortedIndex].normNumerator514			if i > num/denom || (i == num/denom && num%denom == 0) {515				chosenCounts[sortedIndex]++516				saveIndex(i, sortedNormalizedIndexes[sortedIndex].originalIndex, denom)517				break518			}519		}520	}521	return &ExecutionSegmentSequenceWrapper{ExecutionSegmentSequence: ess, lcd: lcd, offsets: offsets}522}523// LCD returns the (cached) least common denominator of the sequence - no need524// to calculate it again, since we did it in the constructor.525func (essw *ExecutionSegmentSequenceWrapper) LCD() int64 {526	return essw.lcd527}528// ScaleInt64 scales the provided value for the given segment.529func (essw *ExecutionSegmentSequenceWrapper) ScaleInt64(segmentIndex int, value int64) int64 {530	start := essw.offsets[segmentIndex][0]531	offsets := essw.offsets[segmentIndex][1:]532	result := (value / essw.lcd) * int64(len(offsets))533	for gi, i := 0, start; i < value%essw.lcd; gi, i = gi+1, i+offsets[gi] {534		result++535	}536	return result537}538// GetStripedOffsets returns the stripped offsets for the given segment539// the returned values are as follows in order:540// - start: the first value that is for the segment541// - offsets: a list of offsets from the previous value for the segment. This are only the offsets542//            to from the start to the next start if we chunk the elements we are going to strip543//            into lcd sized chunks544// - lcd: the LCD of the lengths of all segments in the sequence. This is also the number of545//        elements after which the algorithm starts to loop and give the same values546func (essw *ExecutionSegmentSequenceWrapper) GetStripedOffsets(segmentIndex int) (int64, []int64, int64) {547	offsets := essw.offsets[segmentIndex]548	return offsets[0], offsets[1:], essw.lcd549}550// GetTuple returns an ExecutionTuple for the specified segment index.551func (essw *ExecutionSegmentSequenceWrapper) GetTuple(segmentIndex int) *ExecutionTuple {552	return &ExecutionTuple{553		Sequence:     essw,554		Segment:      essw.ExecutionSegmentSequence[segmentIndex],555		SegmentIndex: segmentIndex,556	}557}558// GetNewExecutionSegmentSequenceFromValue uses the value provided, splits it559// between all the segments, using the striping offsets in the sequence,560// generating a new segment sequence. It then returns a new561// ExecutionSegmentSequenceWrapper, with the new sequence and segments, such562// that each new segment in the new sequence has length `Scale(value)/value`563// while keeping the order.564//565// Additionally, the position of a given segment index can be tracked (since566// empty segments are removed), so that you can reconstruct an ExecutionTuple,567// if required. If the segment with the trackedIndex is not part of the new568// sequence, or if a new sequence cannot be generated (for example, for 0569// values), an error will be returned.570func (essw *ExecutionSegmentSequenceWrapper) GetNewExecutionSegmentSequenceFromValue(value int64, trackedIndex int) (571	newSequence *ExecutionSegmentSequenceWrapper, newIndex int, err error,572) {573	if value < 1 {574		return nil, -1, fmt.Errorf("cannot generate new sequence for value %d", value)575	}576	if value%essw.lcd == 0 { // the value is perfectly divisible so we will get the same tuple577		return essw, trackedIndex, nil578	}579	newIndex = -1580	newESS := make(ExecutionSegmentSequence, 0, len(essw.ExecutionSegmentSequence)) // this can be smaller581	prev := int64(0)582	for i := range essw.ExecutionSegmentSequence {583		newValue := essw.ScaleInt64(i, value)584		if newValue == 0 {585			continue586		}587		currentES := newExecutionSegment(big.NewRat(prev, value), big.NewRat(prev+newValue, value))588		prev += newValue589		if i == trackedIndex {590			newIndex = len(newESS)591		}592		newESS = append(newESS, currentES)593	}594	if newIndex == -1 {595		return nil, -1, fmt.Errorf(596			"segment %d (%s) isn't present in the new sequence",597			trackedIndex, essw.ExecutionSegmentSequence[trackedIndex],598		)599	}600	return NewExecutionSegmentSequenceWrapper(newESS), newIndex, nil601}602// ExecutionTuple is the combination of an ExecutionSegmentSequence(Wrapper) and603// a specific ExecutionSegment from it. It gives easy access to the efficient604// scaling and striping algorithms for that specific segment, since the results605// are cached in the sequence wrapper. It is also the basis for the606// SegmentedIndex type below, which is the actual implementation of a segmented607// (striped) iterator, usable both for segmenting actual iterations and for608// partitioning data between multiple instances.609//610// For example, let's try to segment a load test in 3 unequal parts: 50%, 25%611// and 25% (so the ExecutionSegmentSequence will contain these segments: 0:1/2,612// 1/2:3/4, 3/4:1). The building blocks that k6 needs for distributed execution613// are segmented (non-overlapping) iterators and proportionally dividing integer614// numbers as fairly as possible between multiple segments in a stable manner.615//616// The segmented iterators (i.e. SegmentedIndex values below) will be like this:617//618//  Normal iterator:              0   1   2   3   4   5   6   7   8   9   10  11 ...619//  Instance 1 (0:1/2) iterator:  0       2       4       6       8       10     ...620//  Instance 2 (1/2:3/4) iterator:    1               5               9          ...621//  Instance 2 (3/4:1) iterator:              3               7               11 ...622//623// See how every instance has its own uniqe non-overlapping iterator, but when624// we combine all of them, we cover every possible value in the original one.625//626// We also can use this property to scale integer numbers proportionally, as627// fairly as possible, between the instances, like this:628//629//  Global int value to scale:    1   2   3   4   5   6   7   8   9   10  11  12 ...630//  Calling ScaleInt64():631//  - Instance 1 (0:1/2) value:   1   1   2   2   3   3   4   4   5   5   6   6  ...632//  - Instance 2 (1/2:3/4) value: 0   1   1   1   1   2   2   2   2   3   3   3  ...633//  - Instance 2 (3/4:1) value:   0   0   0   1   1   1   1   2   2   2   2   3  ...634//635// Notice how the sum of the per-instance values is always equal to the global636// value - this is what ExecutionTuple.ScaleInt64() does. Also compare both637// tables (their positions match), see how we only increment the value for a638// particular instance when we would have cycled the iterator on that step.639//640// This also makes the scaling stable, in contrast to ExecutionSegment.Scale().641// Scaled values will only ever increase, since we just increment them in a642// specific order between instances. There will never be a situation where643// `ScaleInt64(i)` is less than `ScaleInt64(i+n)` for any positive n!644//645// The algorithm that calculates the offsets and everything that's necessary to646// have these segmented iterators is in NewExecutionSegmentSequenceWrapper().647// The ExecutionTuple simply exposes them efficiently for a single segment of648// the sequence, so it's the thing that most users will probably need.649type ExecutionTuple struct { // TODO rename? make fields private and have getter methods?650	Sequence     *ExecutionSegmentSequenceWrapper651	Segment      *ExecutionSegment652	SegmentIndex int653}654func (et *ExecutionTuple) String() string {655	return fmt.Sprintf("%s in %s", et.Segment, et.Sequence)656}657// NewExecutionTuple returns a new ExecutionTuple for the provided segment and658// sequence.659//660// TODO: don't return a pointer?661func NewExecutionTuple(segment *ExecutionSegment, sequence *ExecutionSegmentSequence) (*ExecutionTuple, error) {662	filledSeq := GetFilledExecutionSegmentSequence(sequence, segment)663	wrapper := NewExecutionSegmentSequenceWrapper(filledSeq)664	index, err := wrapper.FindSegmentPosition(segment)665	if err != nil {666		return nil, err667	}668	return &ExecutionTuple{Sequence: wrapper, Segment: segment, SegmentIndex: index}, nil669}670// ScaleInt64 scales the provided value for our execution segment.671func (et *ExecutionTuple) ScaleInt64(value int64) int64 {672	if len(et.Sequence.ExecutionSegmentSequence) == 1 {673		return value // if we don't have any segmentation, just return the original value674	}675	return et.Sequence.ScaleInt64(et.SegmentIndex, value)676}677// GetStripedOffsets returns the striped offsets for our execution segment....

NewExecutionSegmentSequenceWrapper

Using AI Code Generation

1func main() {2}3func main() {4}5func main() {6}7func main() {8}9func main() {10}11func main() {12}13func main() {14}15func main() {16}17func main() {18}19func main() {20}21func main() {22}23func main() {24}25func main() {

NewExecutionSegmentSequenceWrapper

Using AI Code Generation

1func main() {2    seq, err := lib.NewExecutionSegmentSequenceWrapper("1/2,2/3")3    if err != nil {4        log.Fatal(err)5    }6    seq, err = lib.NewExecutionSegmentSequenceWrapper("1/2,2/3")7    if err != nil {8        log.Fatal(err)9    }10    seq, err = lib.NewExecutionSegmentSequenceWrapper("1/2,2/3")11    if err != nil {12        log.Fatal(err)13    }14    seq, err = lib.NewExecutionSegmentSequenceWrapper("1/2,2/3")15    if err != nil {16        log.Fatal(err)17    }18    seq, err = lib.NewExecutionSegmentSequenceWrapper("1/2,2/3")19    if err != nil {20        log.Fatal(err)21    }22    seq, err = lib.NewExecutionSegmentSequenceWrapper("1/2,2/3")23    if err != nil {24        log.Fatal(err)25    }26    seq, err = lib.NewExecutionSegmentSequenceWrapper("1/2,2/3")27    if err != nil {28        log.Fatal(err)29    }30    seq, err = lib.NewExecutionSegmentSequenceWrapper("1/2,2/3")31    if err != nil {32        log.Fatal(err)33    }34    seq, err = lib.NewExecutionSegmentSequenceWrapper("1/2,2/3")35    if err != nil {36        log.Fatal(err)37    }38    seq, err = lib.NewExecutionSegmentSequenceWrapper("1/2,2/3")39    if err != nil {40        log.Fatal(err)41    }42    seq, err = lib.NewExecutionSegmentSequenceWrapper("1/2,2/3")43    if err != nil {44        log.Fatal(err)45    }46    seq, err = lib.NewExecutionSegmentSequenceWrapper("1/2,2/3")

NewExecutionSegmentSequenceWrapper

Using AI Code Generation

1import (2func main() {3	series := []lib.Series{4		{Name: "test1", Tags: map[string]string{"tag1": "val1"}},5		{Name: "test2", Tags: map[string]string{"tag1": "val2"}},6		{Name: "test3", Tags: map[string]string{"tag1": "val3"}},7	}8	essw := lib.NewExecutionSegmentSequenceWrapper(series, 3)9	for i, s := range essw.Series {10		fmt.Printf("series %d: %s11	}12}13import (14func main() {15	series := []lib.Series{16		{Name: "test1", Tags: map[string]string{"tag1": "val1"}},17		{Name: "test2", Tags: map[string]string{"tag1": "val2"}},18		{Name: "test3", Tags: map[string]string{"tag1": "val3"}},19	}20	essw := lib.NewExecutionSegmentSequenceWrapper(series, 2)21	for i, s := range essw.Series {22		fmt.Printf("series %d: %s23	}24}25import (26func main() {27	series := []lib.Series{28		{Name: "test1", Tags: map[string]string{"tag1": "val1"}},29		{Name: "test2", Tags: map[string]string{"tag1": "val2"}},30		{Name: "test3", Tags: map[string]string{"tag1": "val3

NewExecutionSegmentSequenceWrapper

Using AI Code Generation

1func main() {2    sequence := NewExecutionSegmentSequenceWrapper()3    sequence.AddSegmentWrapper(0.0, 0.3)4    sequence.AddSegmentWrapper(0.3, 0.6)5    sequence.AddSegmentWrapper(0.6, 1.0)6    runner := NewRunnerWrapper()7    runner.RunWrapper(sequence)8}9func main() {10    runner := NewRunnerWrapper()11    runner.RunWrapper(nil)12}13func main() {14    runner := NewRunnerWrapper()15    runner.RunWrapper(nil)16}17func main() {18    runner := NewRunnerWrapper()19    runner.RunWrapper(nil)20}21func main() {22    runner := NewRunnerWrapper()23    runner.RunWrapper(nil)24}25func main() {26    runner := NewRunnerWrapper()27    runner.RunWrapper(nil)28}29func main() {30    runner := NewRunnerWrapper()31    runner.RunWrapper(nil)32}33func main() {34    runner := NewRunnerWrapper()35    runner.RunWrapper(nil)36}37func main() {38    runner := NewRunnerWrapper()39    runner.RunWrapper(nil)40}

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