telegraf/plugins/memcached/memcached.go

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package memcached
import (
"bufio"
"bytes"
"fmt"
"net"
"strconv"
"time"
"github.com/influxdb/telegraf/plugins"
)
// Memcached is a memcached plugin
type Memcached struct {
Servers []string
}
var sampleConfig = `
# An array of address to gather stats about. Specify an ip on hostname
# with optional port. ie localhost, 10.0.0.1:11211, etc.
#
# If no servers are specified, then localhost is used as the host.
servers = ["localhost"]
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`
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var defaultTimeout = 5 * time.Second
// The list of metrics tha should be calculated
var sendAsIs = []string{
"get_hits",
"get_misses",
"evictions",
"limit_maxbytes",
"bytes",
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}
// SampleConfig returns sample configuration message
func (m *Memcached) SampleConfig() string {
return sampleConfig
}
// Description returns description of Memcached plugin
func (m *Memcached) Description() string {
return "Read metrics from one or many memcached servers"
}
// Gather reads stats from all configured servers accumulates stats
func (m *Memcached) Gather(acc plugins.Accumulator) error {
if len(m.Servers) == 0 {
return m.gatherServer(":11211", acc)
}
for _, serverAddress := range m.Servers {
if err := m.gatherServer(serverAddress, acc); err != nil {
return err
}
}
return nil
}
func (m *Memcached) gatherServer(address string, acc plugins.Accumulator) error {
_, _, err := net.SplitHostPort(address)
if err != nil {
address = address + ":11211"
}
// Connect
conn, err := net.DialTimeout("tcp", address, defaultTimeout)
if err != nil {
return err
}
defer conn.Close()
// Extend connection
conn.SetDeadline(time.Now().Add(defaultTimeout))
// Read and write buffer
rw := bufio.NewReadWriter(bufio.NewReader(conn), bufio.NewWriter(conn))
// Send command
if _, err = fmt.Fprint(rw, "stats\r\n"); err != nil {
return err
}
if err = rw.Flush(); err != nil {
return err
}
// Read response
values := make(map[string]string)
for {
// Read line
line, _, errRead := rw.Reader.ReadLine()
if errRead != nil {
return errRead
}
// Done
if bytes.Equal(line, []byte("END")) {
break
}
// Read values
s := bytes.SplitN(line, []byte(" "), 3)
if len(s) != 3 || !bytes.Equal(s[0], []byte("STAT")) {
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return fmt.Errorf("unexpected line in stats response: %q", line)
}
// Save values
values[string(s[1])] = string(s[2])
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}
// Add server address as a tag
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tags := map[string]string{"server": address}
// Process values
for _, key := range sendAsIs {
if value, ok := values[key]; ok {
// Mostly it is the number
if iValue, errParse := strconv.ParseInt(value, 10, 64); errParse != nil {
acc.Add(key, value, tags)
} else {
acc.Add(key, iValue, tags)
}
}
}
return nil
}
func init() {
plugins.Add("memcached", func() plugins.Plugin {
return &Memcached{}
})
}