NewMemcached makes a new Memcached.
(cfg MemcachedConfig, client MemcachedClient, name string, reg prometheus.Registerer, logger log.Logger)
| 51 | |
| 52 | // NewMemcached makes a new Memcached. |
| 53 | func NewMemcached(cfg MemcachedConfig, client MemcachedClient, name string, reg prometheus.Registerer, logger log.Logger) *Memcached { |
| 54 | c := &Memcached{ |
| 55 | cfg: cfg, |
| 56 | memcache: client, |
| 57 | name: name, |
| 58 | logger: logger, |
| 59 | requestDuration: instr.NewHistogramCollector( |
| 60 | promauto.With(reg).NewHistogramVec(prometheus.HistogramOpts{ |
| 61 | Namespace: "cortex", |
| 62 | Name: "memcache_request_duration_seconds", |
| 63 | Help: "Total time spent in seconds doing memcache requests.", |
| 64 | // Memcached requests are very quick: smallest bucket is 16us, biggest is 1s |
| 65 | Buckets: prometheus.ExponentialBuckets(0.000016, 4, 8), |
| 66 | ConstLabels: prometheus.Labels{"name": name}, |
| 67 | }, []string{"method", "status_code"}), |
| 68 | ), |
| 69 | } |
| 70 | |
| 71 | if cfg.BatchSize == 0 || cfg.Parallelism == 0 { |
| 72 | return c |
| 73 | } |
| 74 | |
| 75 | c.inputCh = make(chan *work) |
| 76 | c.quit = make(chan struct{}) |
| 77 | c.wg.Add(cfg.Parallelism) |
| 78 | |
| 79 | for i := 0; i < cfg.Parallelism; i++ { |
| 80 | go func() { |
| 81 | defer c.wg.Done() |
| 82 | for { |
| 83 | select { |
| 84 | case <-c.quit: |
| 85 | return |
| 86 | case input := <-c.inputCh: |
| 87 | res := &result{ |
| 88 | batchID: input.batchID, |
| 89 | } |
| 90 | res.found, res.bufs, res.missed = c.fetch(input.ctx, input.keys) |
| 91 | // No-one will be reading from resultCh if we were asked to quit |
| 92 | // during the fetch, so check again before writing to it. |
| 93 | select { |
| 94 | case <-c.quit: |
| 95 | return |
| 96 | case input.resultCh <- res: |
| 97 | } |
| 98 | } |
| 99 | } |
| 100 | }() |
| 101 | } |
| 102 | |
| 103 | return c |
| 104 | } |
| 105 | |
| 106 | type work struct { |
| 107 | keys []string |