Use Cloudwatch options in the struct itself, which is cleaner
Eric Feliksik
6 years ago
| 30 | 30 | // |
| 31 | 31 | // To regularly report metrics to CloudWatch, use the WriteLoop helper method. |
| 32 | 32 | type CloudWatch struct { |
| 33 | mtx sync.RWMutex | |
| 34 | sem chan struct{} | |
| 35 | namespace string | |
| 36 | svc cloudwatchiface.CloudWatchAPI | |
| 37 | counters *lv.Space | |
| 38 | gauges *lv.Space | |
| 39 | histograms *lv.Space | |
| 40 | *cwoptions | |
| 41 | } | |
| 42 | ||
| 43 | type cwoptions struct { | |
| 33 | mtx sync.RWMutex | |
| 34 | sem chan struct{} | |
| 35 | namespace string | |
| 36 | svc cloudwatchiface.CloudWatchAPI | |
| 37 | counters *lv.Space | |
| 38 | gauges *lv.Space | |
| 39 | histograms *lv.Space | |
| 44 | 40 | percentiles Percentiles |
| 45 | 41 | logger log.Logger |
| 46 | 42 | numConcurrentRequests int |
| 47 | 43 | } |
| 48 | 44 | |
| 49 | type option func(*cwoptions) | |
| 50 | ||
| 51 | func (s *cwoptions) apply(opt option) { | |
| 45 | type option func(*CloudWatch) | |
| 46 | ||
| 47 | func (s *CloudWatch) apply(opt option) { | |
| 52 | 48 | if opt != nil { |
| 53 | 49 | opt(s) |
| 54 | 50 | } |
| 55 | 51 | } |
| 56 | 52 | |
| 57 | 53 | func WithLogger(logger log.Logger) option { |
| 58 | return func(o *cwoptions) { | |
| 59 | o.logger = logger | |
| 54 | return func(c *CloudWatch) { | |
| 55 | c.logger = logger | |
| 60 | 56 | } |
| 61 | 57 | } |
| 62 | 58 | |
| 63 | 59 | func WithPercentiles(p Percentiles) option { |
| 64 | return func(o *cwoptions) { | |
| 60 | return func(c *CloudWatch) { | |
| 65 | 61 | validated := Percentiles{} |
| 66 | 62 | for _, entry := range p { |
| 67 | 63 | if entry.f < 0 || entry.f > 1 { |
| 69 | 65 | } |
| 70 | 66 | validated = append(validated, entry) |
| 71 | 67 | } |
| 72 | o.percentiles = validated | |
| 68 | c.percentiles = validated | |
| 73 | 69 | } |
| 74 | 70 | } |
| 75 | 71 | |
| 76 | 72 | func WithConcurrentRequests(n int) option { |
| 77 | return func(o *cwoptions) { | |
| 73 | return func(c *CloudWatch) { | |
| 78 | 74 | if n > maxConcurrentRequests { |
| 79 | 75 | n = maxConcurrentRequests |
| 80 | 76 | } |
| 81 | o.numConcurrentRequests = n | |
| 77 | c.numConcurrentRequests = n | |
| 82 | 78 | } |
| 83 | 79 | } |
| 84 | 80 | |
| 87 | 83 | // Callers must ensure that regular calls to Send are performed, either |
| 88 | 84 | // manually or with one of the helper methods. |
| 89 | 85 | func New(namespace string, svc cloudwatchiface.CloudWatchAPI, options ...option) *CloudWatch { |
| 90 | useOptions := &cwoptions{ | |
| 86 | cw := &CloudWatch{ | |
| 87 | sem: nil, // set below | |
| 88 | namespace: namespace, | |
| 89 | svc: svc, | |
| 90 | counters: lv.NewSpace(), | |
| 91 | gauges: lv.NewSpace(), | |
| 92 | histograms: lv.NewSpace(), | |
| 91 | 93 | numConcurrentRequests: 10, |
| 92 | 94 | logger: log.NewLogfmtLogger(os.Stderr), |
| 93 | 95 | percentiles: Percentiles{ |
| 98 | 100 | }, |
| 99 | 101 | } |
| 100 | 102 | |
| 101 | for _, opt := range options { | |
| 102 | useOptions.apply(opt) | |
| 103 | } | |
| 104 | ||
| 105 | return &CloudWatch{ | |
| 106 | sem: make(chan struct{}, useOptions.numConcurrentRequests), | |
| 107 | namespace: namespace, | |
| 108 | svc: svc, | |
| 109 | counters: lv.NewSpace(), | |
| 110 | gauges: lv.NewSpace(), | |
| 111 | histograms: lv.NewSpace(), | |
| 112 | cwoptions: useOptions, | |
| 113 | } | |
| 103 | for _, optFunc := range options { | |
| 104 | optFunc(cw) | |
| 105 | } | |
| 106 | ||
| 107 | cw.sem = make(chan struct{}, cw.numConcurrentRequests) | |
| 108 | ||
| 109 | return cw | |
| 114 | 110 | } |
| 115 | 111 | |
| 116 | 112 | // NewCounter returns a counter. Observations are aggregated and emitted once |