120 lines
3.0 KiB
Go
120 lines
3.0 KiB
Go
package doormen
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import (
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"encoding/json"
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"errors"
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"fmt"
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"strconv"
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"time"
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"github.com/didiercrunch/doorman/shared"
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"gopkg.in/mgo.v2/bson"
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)
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const epsilon float64 = 0.0001
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type DoormanValue struct {
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Name string `json:"name" bson:"name"`
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Probability float64 `json:"probability" bson:"probability"`
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}
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type DoormanId struct {
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Id bson.ObjectId `json:"id,omitempty" bson:"_id"`
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Name string `json:"name" bson:"name"`
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}
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func (wId *DoormanId) AsJson() string {
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if wId.Id == "" {
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return `{}`
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}
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return fmt.Sprintf(`{"%v":"%v"}`, wId.Id.Hex(), wId.Name)
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}
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type DoormanDefinition struct {
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Id bson.ObjectId `json:"id,omitempty" bson:"_id"`
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Name string `json:"name" bson:"name"`
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Values []*DoormanValue `json:"values" bson:"values"`
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}
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func NewDoormanDefinition(name string) *DoormanDefinition {
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return &DoormanDefinition{Id: bson.NewObjectId(), Name: name}
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}
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// a way to quickly create doormen in tests. do not use in real code. will
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// panic if a doorman is wrongly specify
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func QuickNewDoormanDefinition(name string, probs ...float64) *DoormanDefinition {
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ret := NewDoormanDefinition(name)
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for i, prob := range probs {
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ret.Values = append(ret.Values, &DoormanValue{"T" + strconv.Itoa(i), prob})
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}
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if err := ret.Validate(); err != nil {
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panic(err)
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}
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return ret
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}
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func (dmd *DoormanDefinition) ValidateDoormanValueNames() error {
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m := make(map[string]bool)
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for _, w := range dmd.Values {
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if name := w.Name; name == "" {
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return errors.New("doorman value cannot be empty")
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} else {
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m[name] = true
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}
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}
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if len(m) != len(dmd.Values) {
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return errors.New("doorman value names must be unique within a doorman")
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}
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return nil
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}
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func (dmd *DoormanDefinition) ValidateDoormanValueProbabilities() error {
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var sum float64 = 0
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for _, w := range dmd.Values {
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if p := w.Probability; p < 0-epsilon || p > 1+epsilon {
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return errors.New(fmt.Sprintf("doorman value %v is out of range", p))
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} else {
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sum += p
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}
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}
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if sum < 1-epsilon || sum > 1+epsilon {
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return errors.New("the sum of the probability must be 1.0")
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}
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return nil
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}
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func (dmd *DoormanDefinition) Validate() (err error) {
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switch {
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case dmd.Name == "":
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err = errors.New("name cannot be empty")
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case len(dmd.Values) < 2:
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err = errors.New("need at least 2 values")
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case dmd.ValidateDoormanValueNames() != nil:
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err = dmd.ValidateDoormanValueNames()
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case dmd.ValidateDoormanValueProbabilities() != nil:
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err = dmd.ValidateDoormanValueProbabilities()
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}
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return
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}
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func (dmd *DoormanDefinition) CanBeUpdatedBy(dmd2 *DoormanDefinition) error {
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if dmd.Name != dmd2.Name {
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return errors.New("cannot change doorman name")
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}
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if len(dmd.Values) != len(dmd2.Values) {
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return errors.New("cannot change the number of cases in doorman")
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}
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return nil
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}
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func (dmd *DoormanDefinition) AsDoormanUpdatePayload() ([]byte, error) {
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wu := &shared.DoormanUpdater{Id: dmd.Id.Hex()}
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wu.Timestamp = time.Now().Unix()
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wu.Probabilities = make([]float64, len(dmd.Values))
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for i, value := range dmd.Values {
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wu.Probabilities[i] = value.Probability
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}
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return json.Marshal(wu)
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}
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