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Scrape admin requests #52

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Scrape admin requests #52

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192 changes: 182 additions & 10 deletions main.go
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,8 +2,10 @@ package main

import (
"bufio"
"bytes"
"flag"
"fmt"
"io"
"math"
"net"
"net/http"
Expand All @@ -26,10 +28,11 @@ const (
)

type Exporter struct {
server string
timeout time.Duration
server_stats bool
logger log.Logger
server string
timeout time.Duration
server_stats bool
admin_requests bool
logger log.Logger

up *prometheus.Desc
startTime *prometheus.Desc
Expand Down Expand Up @@ -84,15 +87,21 @@ type Exporter struct {
serverMemcachedTimeout *prometheus.Desc
serverMemcachedSoftTKO *prometheus.Desc
serverMemcachedHardTKO *prometheus.Desc
adminRequestVersion *prometheus.Desc
adminRequestConfigAge *prometheus.Desc
adminRequestConfigFile *prometheus.Desc
adminRequestHostId *prometheus.Desc
adminRequestConfigMD5Digest *prometheus.Desc
}

// NewExporter returns an initialized exporter.
func NewExporter(server string, timeout time.Duration, server_stats bool, logger log.Logger) *Exporter {
func NewExporter(server string, timeout time.Duration, server_stats bool, admin_requests bool, logger log.Logger) *Exporter {
return &Exporter{
server: server,
timeout: timeout,
server_stats: server_stats,
logger: logger,
server: server,
timeout: timeout,
server_stats: server_stats,
admin_requests: admin_requests,
logger: logger,

up: prometheus.NewDesc(
prometheus.BuildFQName(namespace, "", "up"),
Expand Down Expand Up @@ -413,6 +422,36 @@ func NewExporter(server string, timeout time.Duration, server_stats bool, logger
[]string{"server"},
nil,
),
adminRequestVersion: prometheus.NewDesc(
prometheus.BuildFQName(namespace, "", "admin_request_version"),
"Version string of the build (same string as returned by version).",
[]string{"version"},
nil,
),
adminRequestConfigAge: prometheus.NewDesc(
prometheus.BuildFQName(namespace, "", "admin_request_config_age"),
"How long, in seconds, since last config reload.",
nil,
nil,
),
adminRequestConfigFile: prometheus.NewDesc(
prometheus.BuildFQName(namespace, "", "admin_request_config_file"),
"Config file location (error if configured from string).",
[]string{"file"},
nil,
),
adminRequestHostId: prometheus.NewDesc(
prometheus.BuildFQName(namespace, "", "admin_request_host_id"),
"Hostid of this mcrouter instance, an unsigned 32-bit integer in decimal.",
[]string{"host_id"},
nil,
),
adminRequestConfigMD5Digest: prometheus.NewDesc(
prometheus.BuildFQName(namespace, "", "admin_request_config_md5_digest"),
"Current config's md5 hash. Note that this only specifies the main config file's md5 and ignores any additional tracked files.",
[]string{"hash"},
nil,
),
}
}

Expand Down Expand Up @@ -473,6 +512,14 @@ func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
ch <- e.serverMemcachedSoftTKO
ch <- e.serverMemcachedHardTKO
}

if e.admin_requests {
ch <- e.adminRequestVersion
ch <- e.adminRequestConfigAge
ch <- e.adminRequestConfigFile
ch <- e.adminRequestHostId
ch <- e.adminRequestConfigMD5Digest
}
}

// Collect fetches the statistics from the configured mcrouter server, and
Expand Down Expand Up @@ -632,6 +679,65 @@ func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
e.serverMemcachedHardTKO, prometheus.GaugeValue, e.parse(metrics, "hard_tko"), server)
}
}

if e.admin_requests {
version, err := getAdminRequest(conn, "__mcrouter__.version")
if err != nil {
ch <- prometheus.MustNewConstMetric(e.up, prometheus.GaugeValue, 0)
level.Error(e.logger).Log("msg", "Failed to collect version", "err", err)
return
}

ch <- prometheus.MustNewConstMetric(
e.adminRequestVersion, prometheus.GaugeValue, 1, string(version))

configAgeStr, err := getAdminRequest(conn, "__mcrouter__.config_age")
if err != nil {
ch <- prometheus.MustNewConstMetric(e.up, prometheus.GaugeValue, 0)
level.Error(e.logger).Log("msg", "Failed to collect config age", "err", err)
return
}

configAge, err := strconv.ParseFloat(string(configAgeStr), 64)
if err != nil {
ch <- prometheus.MustNewConstMetric(e.up, prometheus.GaugeValue, 0)
level.Error(e.logger).Log("msg", "Failed to collect config age", "err", err)
return
}

ch <- prometheus.MustNewConstMetric(
e.adminRequestConfigAge, prometheus.GaugeValue, configAge)

configFile, err := getAdminRequest(conn, "__mcrouter__.config_file")
if err != nil {
ch <- prometheus.MustNewConstMetric(e.up, prometheus.GaugeValue, 0)
level.Error(e.logger).Log("msg", "Failed to collect config file", "err", err)
return
}

ch <- prometheus.MustNewConstMetric(
e.adminRequestConfigFile, prometheus.GaugeValue, 1, string(configFile))

hostId, err := getAdminRequest(conn, "__mcrouter__.hostid")
if err != nil {
ch <- prometheus.MustNewConstMetric(e.up, prometheus.GaugeValue, 0)
level.Error(e.logger).Log("msg", "Failed to collect host id", "err", err)
return
}

ch <- prometheus.MustNewConstMetric(
e.adminRequestHostId, prometheus.GaugeValue, 1, string(hostId))

config_md5_digest, err := getAdminRequest(conn, "__mcrouter__.config_md5_digest")
if err != nil {
ch <- prometheus.MustNewConstMetric(e.up, prometheus.GaugeValue, 0)
level.Error(e.logger).Log("msg", "Failed to collect admin config_md5_digest from mcrouter", "err", err)
return
}

ch <- prometheus.MustNewConstMetric(
e.adminRequestConfigMD5Digest, prometheus.GaugeValue, 1, string(config_md5_digest))
}
}

// Parse a string into a 64 bit float suitable for Prometheus
Expand Down Expand Up @@ -779,6 +885,71 @@ func getServerStats(conn net.Conn) (map[string]map[string]string, error) {
return m, nil
}

func getAdminRequest(conn net.Conn, request string) ([]byte, error) {
var value []byte
fmt.Fprintf(conn, "get "+request+"\r\n")
reader := bufio.NewReader(conn)

for {
line, err := reader.ReadString('\n')
if err != nil {
return nil, err
}

if line == "END\r\n" {
break
}

it := new(item)
size, err := scanGetResponseLine(line, it)
if err != nil {
return nil, err
}

it.Value = make([]byte, size+2)
_, err = io.ReadFull(reader, it.Value)
if err != nil {
it.Value = nil
return nil, err
}
if !bytes.HasSuffix(it.Value, []byte("\r\n")) {
it.Value = nil
return nil, fmt.Errorf("memcache: corrupt get result read")
}

value = it.Value[:size]
}

return value, nil
}

func scanGetResponseLine(line string, it *item) (size int, err error) {
pattern := "VALUE %s %d %d\r\n"
dest := []interface{}{&it.Key, &it.Flags, &size}
n, err := fmt.Sscanf(line, pattern, dest...)
if err != nil || n != len(dest) {
return -1, fmt.Errorf("memcache: unexpected line in get response: %q", line)
}
return size, nil
}

type item struct {
// Key is the Item's key (250 bytes maximum).
Key string

// Value is the Item's value.
Value []byte

// Flags are server-opaque flags whose semantics are entirely
// up to the app.
Flags uint32

// Expiration is the cache expiration time, in seconds: either a relative
// time from now (up to 1 month), or an absolute Unix epoch time.
// Zero means the Item has no expiration time.
Expiration int32
}

func main() {
var (
address = flag.String("mcrouter.address", "localhost:5000", "mcrouter server TCP address (tcp4/tcp6) or UNIX socket path")
Expand All @@ -787,6 +958,7 @@ func main() {
listenAddress = flag.String("web.listen-address", ":9442", "Address to listen on for web interface and telemetry.")
metricsPath = flag.String("web.telemetry-path", "/metrics", "Path under which to expose metrics.")
serverMetrics = flag.Bool("mcrouter.server_metrics", false, "Collect per-server metrics.")
adminRequests = flag.Bool("mcrouter.admin_requests", false, "Collect admin requests.")
logLevel = flag.String(promlogflag.LevelFlagName, "info", promlogflag.LevelFlagHelp)
logFormat = flag.String(promlogflag.FormatFlagName, "logfmt", promlogflag.FormatFlagHelp)
)
Expand Down Expand Up @@ -816,7 +988,7 @@ func main() {
level.Info(logger).Log("msg", "Starting mcrouter_exporter", "version", version.Info())
level.Info(logger).Log("msg", "Build context", "build_context", version.BuildContext())

prometheus.MustRegister(NewExporter(*address, *timeout, *serverMetrics, logger))
prometheus.MustRegister(NewExporter(*address, *timeout, *serverMetrics, *adminRequests, logger))
http.Handle(*metricsPath, promhttp.Handler())
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
//nolint:errcheck
Expand Down
122 changes: 122 additions & 0 deletions main_test.go
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,36 @@ func handleRequestServerStats(conn net.Conn, full bool) {
conn.Close()
}

func handleAdminRequest(conn net.Conn) {
buf := make([]byte, 1024)
n, err := conn.Read(buf)
if err != nil {
fmt.Println("Error reading:", err.Error())
}

var ret []byte

command := string(buf[:n])

switch command {
case "get __mcrouter__.version\r\n":
ret = []byte("VALUE __mcrouter__.version 0 15\r\n40.0.0 mcrouter\r\nEND\r\n")
case "get __mcrouter__.config_age\r\n":
ret = []byte("VALUE __mcrouter__.config_age 0 7\r\n1040469\r\nEND\r\n")
case "get __mcrouter__.config_file\r\n":
ret = []byte("VALUE __mcrouter__.config_file 0 32\r\n/opt/mcrouter/config/config.json\r\nEND\r\n")
case "get __mcrouter__.hostid\r\n":
ret = []byte("VALUE __mcrouter__.hostid 0 10\r\n4079863250\r\nEND\r\n")
case "get __mcrouter__.config_md5_digest\r\n":
ret = []byte("VALUE __mcrouter__.config_md5_digest 0 32\r\n2aa22ce671e9fdf6a7bb762f9a6cb0cc\r\nEND\r\n")
default:
ret = []byte("unknown command\r\nEND\r\n")
}

conn.Write(ret)
conn.Close()
}

func TestStatsParsing(t *testing.T) {
Convey("Given a remote mcrouter stats endpoint", t, func() {
server, client := net.Pipe()
Expand Down Expand Up @@ -138,3 +168,95 @@ func TestServerStatsParsingAfterMcrouterBootstrap(t *testing.T) {

})
}

func TestAdminRequestParsing(t *testing.T) {
Convey("Given a remote mcrouter admin request server version", t, func() {
server, client := net.Pipe()
go func() {
go handleAdminRequest(server)
}()

Convey("When scraped by our client", func() {
data, err := getAdminRequest(client, "__mcrouter__.version")
if err != nil {
t.Fatal(err)
}
Convey("It should parse the version", func() {
expected := []byte("40.0.0 mcrouter")
So(data, ShouldResemble, expected)
})
})
})

Convey("Given a remote mcrouter admin request server config_age", t, func() {
server, client := net.Pipe()
go func() {
go handleAdminRequest(server)
}()

Convey("When scraped by our client", func() {
data, err := getAdminRequest(client, "__mcrouter__.config_age")
if err != nil {
t.Fatal(err)
}
Convey("It should parse the config age", func() {
expected := []byte("1040469")
So(data, ShouldResemble, expected)
})
})
})

Convey("Given a remote mcrouter admin request server config_file", t, func() {
server, client := net.Pipe()
go func() {
go handleAdminRequest(server)
}()

Convey("When scraped by our client", func() {
data, err := getAdminRequest(client, "__mcrouter__.config_file")
if err != nil {
t.Fatal(err)
}
Convey("It should parse the config file", func() {
expected := []byte("/opt/mcrouter/config/config.json")
So(data, ShouldResemble, expected)
})
})
})

Convey("Given a remote mcrouter admin request server hostid", t, func() {
server, client := net.Pipe()
go func() {
go handleAdminRequest(server)
}()

Convey("When scraped by our client", func() {
data, err := getAdminRequest(client, "__mcrouter__.hostid")
if err != nil {
t.Fatal(err)
}
Convey("It should parse the hostid", func() {
expected := []byte("4079863250")
So(data, ShouldResemble, expected)
})
})
})

Convey("Given a remote mcrouter admin request server config_md5_digest", t, func() {
server, client := net.Pipe()
go func() {
go handleAdminRequest(server)
}()

Convey("When scraped by our client", func() {
data, err := getAdminRequest(client, "__mcrouter__.config_md5_digest")
if err != nil {
t.Fatal(err)
}
Convey("It should parse the config_md5_digest", func() {
expected := []byte("2aa22ce671e9fdf6a7bb762f9a6cb0cc")
So(data, ShouldResemble, expected)
})
})
})
}