Unleash/unleash-client-go

package strategies

import (
    "github.com/Unleash/unleash-client-go/v3/context"
    "github.com/Unleash/unleash-client-go/v3/strategy"
)

type stickiness string

const (
    defaultStickiness stickiness = "default"
    randomStickiness  stickiness = "random"
)

type flexibleRolloutStrategy struct {
    random *rng
}

// NewFlexibleRolloutStrategy creates a new instance of the flexible rollout strategy.
func NewFlexibleRolloutStrategy() *flexibleRolloutStrategy {
    s := &flexibleRolloutStrategy{
        random: newRng(),
    }
    return s
}

func (s flexibleRolloutStrategy) Name() string {
    return "flexibleRollout"
}

func (s flexibleRolloutStrategy) resolveStickiness(st stickiness, ctx context.Context) string {
    switch st {
    case defaultStickiness:
        return coalesce(ctx.UserId, ctx.SessionId, s.random.string())
    case randomStickiness:
        return s.random.string()
    default:
        return ctx.Field(string(st))
    }
}

func (s flexibleRolloutStrategy) IsEnabled(params map[string]interface{}, ctx *context.Context) bool {
    groupID := ""
    if gID, found := params[strategy.ParamGroupId]; found {
        groupID = gID.(string)
    }

    rollout, found := params[strategy.ParamRollout]
    if !found {
        return false
    }

    percentage, ok := parameterAsFloat64(rollout)
    if !ok {
        return false
    }

    sticky := coalesce(params[strategy.ParamStickiness].(string), string(defaultStickiness))
    stickinessID := s.resolveStickiness(stickiness(sticky), *ctx)

    if stickinessID == "" {
        return false
    }

    normalizedID := normalizedValue(stickinessID, groupID)
    return percentage > 0 && float64(normalizedID) <= percentage
}