| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | package memcached |
| 4 | |
| 5 | import ( |
| 6 | "bufio" |
| 7 | "bytes" |
| 8 | "errors" |
| 9 | "strconv" |
| 10 | "strings" |
| 11 | ) |
| 12 | |
| 13 | // https://github.com/memcached/memcached/blob/b1aefcdf8a265f8a5126e8aa107a50988fa1ec35/doc/protocol.txt#L1267 |
| 14 | var statsMetrics = map[string]bool{ |
| 15 | "limit_maxbytes": true, |
| 16 | "bytes": true, |
| 17 | "bytes_read": true, |
| 18 | "bytes_written": true, |
| 19 | "cas_badval": true, |
| 20 | "cas_hits": true, |
| 21 | "cas_misses": true, |
| 22 | "cmd_get": true, |
| 23 | "cmd_set": true, |
| 24 | "cmd_touch": true, |
| 25 | "curr_connections": true, |
| 26 | "curr_items": true, |
| 27 | "decr_hits": true, |
| 28 | "decr_misses": true, |
| 29 | "delete_hits": true, |
| 30 | "delete_misses": true, |
| 31 | "evictions": true, |
| 32 | "get_hits": true, |
| 33 | "get_misses": true, |
| 34 | "incr_hits": true, |
| 35 | "incr_misses": true, |
| 36 | "reclaimed": true, |
| 37 | "rejected_connections": true, |
| 38 | "total_connections": true, |
| 39 | "total_items": true, |
| 40 | "touch_hits": true, |
| 41 | "touch_misses": true, |
| 42 | } |
| 43 | |
| 44 | func (c *Collector) collect() (map[string]int64, error) { |
| 45 | if c.conn == nil { |
| 46 | conn, err := c.establishConn() |
| 47 | if err != nil { |
| 48 | return nil, err |
| 49 | } |
| 50 | c.conn = conn |
| 51 | } |
| 52 | |
| 53 | stats, err := c.conn.queryStats() |
| 54 | if err != nil { |
| 55 | c.conn.disconnect() |
| 56 | c.conn = nil |
| 57 | return nil, err |
| 58 | } |
| 59 | |
| 60 | mx := make(map[string]int64) |
| 61 | |
| 62 | if err := c.collectStats(mx, stats); err != nil { |
| 63 | return nil, err |
| 64 | } |
| 65 | |
| 66 | return mx, nil |
| 67 | } |
| 68 | |
| 69 | func (c *Collector) collectStats(mx map[string]int64, stats []byte) error { |
| 70 | if len(stats) == 0 { |
| 71 | return errors.New("empty stats response") |
| 72 | } |
| 73 | |
| 74 | var n int |
| 75 | sc := bufio.NewScanner(bytes.NewReader(stats)) |
| 76 | |
| 77 | for sc.Scan() { |
| 78 | line := strings.TrimSpace(sc.Text()) |
| 79 | |
| 80 | switch { |
| 81 | case strings.HasPrefix(line, "STAT"): |
| 82 | key, value := getStatKeyValue(line) |
| 83 | if !statsMetrics[key] { |
| 84 | continue |
| 85 | } |
| 86 | if v, err := strconv.ParseInt(value, 10, 64); err == nil { |
| 87 | mx[key] = v |
| 88 | n++ |
| 89 | } |
| 90 | case strings.HasPrefix(line, "ERROR"): |
| 91 | return errors.New("received ERROR response") |
| 92 | } |
| 93 | } |
| 94 | |
| 95 | if n == 0 { |
| 96 | return errors.New("unexpected memcached response") |
| 97 | } |
| 98 | |
| 99 | mx["avail"] = mx["limit_maxbytes"] - mx["bytes"] |
| 100 | |
| 101 | return nil |
| 102 | } |
| 103 | |
| 104 | func (c *Collector) establishConn() (memcachedConn, error) { |
| 105 | conn := c.newMemcachedConn(c.Config) |
| 106 | |
| 107 | if err := conn.connect(); err != nil { |
| 108 | return nil, err |
| 109 | } |
| 110 | |
| 111 | return conn, nil |
| 112 | } |
| 113 | |
| 114 | func getStatKeyValue(line string) (string, string) { |
| 115 | line = strings.TrimPrefix(line, "STAT ") |
| 116 | before, after, ok := strings.Cut(line, " ") |
| 117 | if !ok { |
| 118 | return "", "" |
| 119 | } |
| 120 | return before, after |
| 121 | } |