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| package main | |
| import "strconv" | |
| /////// pkg/dynconfig/key.go | |
| type FloatKey struct { | |
| name string | |
| fallback string | |
| } | |
| func (k FloatKey) load(input string) (interface{}, error) { | |
| return strconv.ParseFloat(input, 64) | |
| } | |
| /////// pkg/dynconfig/register.go | |
| type Key interface { | |
| load(input string) (interface{}, error) | |
| } | |
| type register struct { | |
| m map[string]Key | |
| } | |
| func NewRegister() *register { | |
| return ®ister{ | |
| m: make(map[string]Key), | |
| } | |
| } | |
| func (r *register) Float(name string, fallback string) FloatKey { | |
| // check name | |
| // check presence | |
| key := FloatKey{name: name, fallback: fallback} | |
| r.m[name] = &key | |
| return key | |
| } | |
| /////// pkg/dynconfig/dynkeys/keys.go | |
| var Register = NewRegister() | |
| var RolloutProductionInternal = Register.Float("rollout.production.internal", "0.4") | |
| /////// pkg/dynconfig/service.go | |
| type FetchService struct { | |
| store interface { | |
| Load(name string) (string, error) | |
| } | |
| } | |
| func (s *FetchService) get(name string, fallback string) string { | |
| value, _ := s.store.Load(name) | |
| // cache the value, | |
| // fallback for error | |
| // metrics | |
| return value | |
| } | |
| /////// pkg/dynconfig/values.go | |
| func Float(service *FetchService, key FloatKey) FloatValue { | |
| return FloatValue{service, key} | |
| } | |
| type FloatValue struct { | |
| service *FetchService | |
| key FloatKey | |
| } | |
| func (v *FloatValue) Value() float64 { | |
| str := v.service.get(v.key.name, v.key.fallback) | |
| result, err := v.key.load(str) | |
| if err != nil { | |
| result, _ = v.key.load(v.key.fallback) | |
| } | |
| return result.(float64) | |
| } | |
| /////// pkg/some/client.go | |
| type Client struct { | |
| rollout FloatValue | |
| } | |
| func NewClient(dynservice *FetchService) *Client { | |
| return &Client{ | |
| rollout: Float(dynservice, RolloutProductionInternal), | |
| } | |
| } | |
| func (c *Client) Run() { | |
| for { | |
| if c.rollout.Value() > 0.04 { | |
| // ... | |
| } | |
| } | |
| } |
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