func()

in pkg/pool/pool.go [637:722]
61 lines of code
19 McCabe index (conditional complexity)

func (p *pool) getPDDeviation() int {
	deviationPrefix := 0

	var isWarmIPTargetDefined, isMinIPTargetDefined, isWarmPrefixTargetDefined bool

	// if DesiredSize is 0, it means PD pool is in draining state, then set targets to 0
	if p.warmPoolConfig.DesiredSize == 0 {
		p.warmPoolConfig.WarmIPTarget = 0
		p.warmPoolConfig.MinIPTarget = 0
		p.warmPoolConfig.WarmPrefixTarget = 0
	} else {
		// PD pool is active, check if target values are valid. If so, set defined flag to true
		if p.warmPoolConfig.WarmIPTarget > 0 {
			isWarmIPTargetDefined = true
		}
		if p.warmPoolConfig.MinIPTarget > 0 {
			isMinIPTargetDefined = true
		}
		if p.warmPoolConfig.WarmPrefixTarget > 0 {
			isWarmPrefixTargetDefined = true
		}

		// set target to default values if not defined
		if !isWarmIPTargetDefined {
			if isMinIPTargetDefined || !isWarmPrefixTargetDefined {
				p.warmPoolConfig.WarmIPTarget = config.IPv4PDDefaultWarmIPTargetSize
			}
		}
		if !isMinIPTargetDefined {
			if isWarmIPTargetDefined || !isWarmPrefixTargetDefined {
				p.warmPoolConfig.MinIPTarget = config.IPv4PDDefaultMinIPTargetSize
			}
		}
	}

	numExistingWarmResources := numResourcesFromMap(p.warmResources)
	freePrefixes := findFreeGroup(p.warmResources, NumIPv4AddrPerPrefix)

	// if neither WarmIPTarget nor MinIPTarget defined but WarmPrefixTarget is defined, return deviation needed for warm prefix target
	if !isWarmIPTargetDefined && !isMinIPTargetDefined && isWarmPrefixTargetDefined {
		deviationPrefix = p.warmPoolConfig.WarmPrefixTarget - len(freePrefixes) - utils.CeilDivision(p.pendingCreate, NumIPv4AddrPerPrefix)

		if deviationPrefix != 0 {
			p.log.Info("calculating IP deviation for prefix pool to satisfy warm prefix target", "warm prefix target",
				p.warmPoolConfig.WarmPrefixTarget, "numFreePrefix", len(freePrefixes), "p.pendingCreate", p.pendingCreate,
				"p.pendingDelete", p.pendingDelete, "deviation", deviationPrefix*NumIPv4AddrPerPrefix)
		}

		return deviationPrefix * NumIPv4AddrPerPrefix
	}

	// total resources in pool include used resources, warm resources, pendingCreate (to avoid duplicate request), and coolDownQueue
	numTotalResources := len(p.usedResources) + p.pendingCreate + numExistingWarmResources + len(p.coolDownQueue)
	// number of existing prefixes
	numCurrPrefix := utils.CeilDivision(numTotalResources, 16)

	// number of total resources required to meet WarmIPTarget
	numTotalResForWarmIPTarget := len(p.usedResources) + p.warmPoolConfig.WarmIPTarget
	// number of total prefixes required to meet WarmIPTarget
	numPrefixForWarmIPTarget := utils.CeilDivision(numTotalResForWarmIPTarget, 16)
	// number of prefixes to meet MinIPTarget
	numPrefixForMinIPTarget := utils.CeilDivision(p.warmPoolConfig.MinIPTarget, 16)

	if numPrefixForWarmIPTarget >= numPrefixForMinIPTarget {
		// difference is the number of prefixes to create or delete
		deviationPrefix = numPrefixForWarmIPTarget - numCurrPrefix
	} else {
		// difference is the number of prefixes to create in order to meet MinIPTarget
		deviationPrefix = numPrefixForMinIPTarget - numCurrPrefix
	}

	// if we need to delete prefixes, should check if any prefix is free to be deleted since they can be fragmented. If not, reset deviation
	if deviationPrefix < 0 && len(freePrefixes) == 0 {
		deviationPrefix = 0
	}

	if deviationPrefix != 0 {
		p.log.V(1).Info("calculating IP deviation for prefix pool", "warmPoolConfig", p.warmPoolConfig,
			"used resources", len(p.usedResources), "existing warm resources", numExistingWarmResources, "pendingCreate", p.pendingCreate,
			"pendingDelete", p.pendingDelete, "numTotalResources", numTotalResources, "numCurrPrefix", numCurrPrefix,
			"numTotalResForWarmIPTarget", numTotalResForWarmIPTarget, "numPrefixForWarmIPTarget", numPrefixForWarmIPTarget,
			"numPrefixForMinIPTarget", numPrefixForMinIPTarget, "deviation", deviationPrefix*NumIPv4AddrPerPrefix)
	}

	return deviationPrefix * NumIPv4AddrPerPrefix
}