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exporter.go
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exporter.go
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package main
import (
"context"
"crypto/tls"
"crypto/x509"
"flag"
"fmt"
"io/ioutil"
"log"
"net"
"net/http"
"os"
"os/signal"
"strconv"
"strings"
"syscall"
"time"
plusclient "github.com/nginxinc/nginx-plus-go-client/client"
"github.com/nginxinc/nginx-prometheus-exporter/client"
"github.com/nginxinc/nginx-prometheus-exporter/collector"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
"github.com/prometheus/common/model"
)
func getEnv(key, defaultValue string) string {
value, ok := os.LookupEnv(key)
if !ok {
return defaultValue
}
return value
}
func getEnvUint(key string, defaultValue uint) uint {
value, ok := os.LookupEnv(key)
if !ok {
return defaultValue
}
i, err := strconv.ParseUint(value, 10, 64)
if err != nil {
log.Fatalf("Environment variable value for %s must be an uint: %v", key, err)
}
return uint(i)
}
func getEnvBool(key string, defaultValue bool) bool {
value, ok := os.LookupEnv(key)
if !ok {
return defaultValue
}
b, err := strconv.ParseBool(value)
if err != nil {
log.Fatalf("Environment variable value for %s must be a boolean: %v", key, err)
}
return b
}
func getEnvPositiveDuration(key string, defaultValue time.Duration) positiveDuration {
value, ok := os.LookupEnv(key)
if !ok {
return positiveDuration{defaultValue}
}
posDur, err := parsePositiveDuration(value)
if err != nil {
log.Fatalf("Environment variable value for %s must be a positive duration: %v", key, err)
}
return posDur
}
func getEnvConstLabels(key string, defaultValue map[string]string) constLabel {
value, ok := os.LookupEnv(key)
if !ok {
return constLabel{defaultValue}
}
cLabel, err := parseConstLabels(value)
if err != nil {
log.Fatalf("Environment variable value for %s must be a const label or a list of const labels: %v", key, err)
}
return cLabel
}
// positiveDuration is a wrapper of time.Duration to ensure only positive values are accepted
type positiveDuration struct{ time.Duration }
func (pd *positiveDuration) Set(s string) error {
dur, err := parsePositiveDuration(s)
if err != nil {
return err
}
pd.Duration = dur.Duration
return nil
}
func parsePositiveDuration(s string) (positiveDuration, error) {
dur, err := time.ParseDuration(s)
if err != nil {
return positiveDuration{}, err
}
if dur < 0 {
return positiveDuration{}, fmt.Errorf("negative duration %v is not valid", dur)
}
return positiveDuration{dur}, nil
}
func createPositiveDurationFlag(name string, value positiveDuration, usage string) *positiveDuration {
flag.Var(&value, name, usage)
return &value
}
type constLabel struct{ labels map[string]string }
func (cl *constLabel) Set(s string) error {
labelList, err := parseConstLabels(s)
if err != nil {
return err
}
cl.labels = labelList.labels
return nil
}
func (cl *constLabel) String() string {
return fmt.Sprint(cl.labels)
}
func parseConstLabels(labels string) (constLabel, error) {
if labels == "" {
return constLabel{}, nil
}
constLabels := make(map[string]string)
labelList := strings.Split(labels, ",")
for _, l := range labelList {
dat := strings.Split(l, "=")
if len(dat) != 2 {
return constLabel{}, fmt.Errorf("const label %s has wrong format. Example valid input 'labelName=labelValue'", l)
}
labelName := model.LabelName(dat[0])
if !labelName.IsValid() {
return constLabel{}, fmt.Errorf("const label %s has wrong format. %s contains invalid characters", l, labelName)
}
labelValue := model.LabelValue(dat[1])
if !labelValue.IsValid() {
return constLabel{}, fmt.Errorf("const label %s has wrong format. %s contains invalid characters", l, labelValue)
}
constLabels[dat[0]] = dat[1]
}
return constLabel{labels: constLabels}, nil
}
func createConstLabelsFlag(name string, value constLabel, usage string) *constLabel {
flag.Var(&value, name, usage)
return &value
}
func createClientWithRetries(getClient func() (interface{}, error), retries uint, retryInterval time.Duration) (interface{}, error) {
var err error
var nginxClient interface{}
for i := 0; i <= int(retries); i++ {
nginxClient, err = getClient()
if err == nil {
return nginxClient, nil
}
if i < int(retries) {
log.Printf("Could not create Nginx Client. Retrying in %v...", retryInterval)
time.Sleep(retryInterval)
}
}
return nil, err
}
func parseUnixSocketAddress(address string) (string, string, error) {
addressParts := strings.Split(address, ":")
addressPartsLength := len(addressParts)
if addressPartsLength > 3 || addressPartsLength < 1 {
return "", "", fmt.Errorf("address for unix domain socket has wrong format")
}
unixSocketPath := addressParts[1]
requestPath := ""
if addressPartsLength == 3 {
requestPath = addressParts[2]
}
return unixSocketPath, requestPath, nil
}
func getListener(listenAddress string) (net.Listener, error) {
var listener net.Listener
var err error
if strings.HasPrefix(listenAddress, "unix:") {
path, _, pathError := parseUnixSocketAddress(listenAddress)
if pathError != nil {
return listener, fmt.Errorf("parsing unix domain socket listen address %s failed: %v", listenAddress, pathError)
}
listener, err = net.ListenUnix("unix", &net.UnixAddr{Name: path, Net: "unix"})
} else {
listener, err = net.Listen("tcp", listenAddress)
}
if err != nil {
return listener, err
}
log.Printf("Listening on %s", listenAddress)
return listener, nil
}
var (
// Set during go build
version string
gitCommit string
// Defaults values
defaultListenAddress = getEnv("LISTEN_ADDRESS", ":9113")
defaultMetricsPath = getEnv("TELEMETRY_PATH", "/metrics")
defaultNginxPlus = getEnvBool("NGINX_PLUS", false)
defaultScrapeURI = getEnv("SCRAPE_URI", "http://127.0.0.1:8080/stub_status")
defaultSslVerify = getEnvBool("SSL_VERIFY", true)
defaultSslCaCert = getEnv("SSL_CA_CERT", "")
defaultSslClientCert = getEnv("SSL_CLIENT_CERT", "")
defaultSslClientKey = getEnv("SSL_CLIENT_KEY", "")
defaultTimeout = getEnvPositiveDuration("TIMEOUT", time.Second*5)
defaultNginxRetries = getEnvUint("NGINX_RETRIES", 0)
defaultNginxRetryInterval = getEnvPositiveDuration("NGINX_RETRY_INTERVAL", time.Second*5)
defaultConstLabels = getEnvConstLabels("CONST_LABELS", map[string]string{})
// Command-line flags
listenAddr = flag.String("web.listen-address",
defaultListenAddress,
"An address or unix domain socket path to listen on for web interface and telemetry. The default value can be overwritten by LISTEN_ADDRESS environment variable.")
metricsPath = flag.String("web.telemetry-path",
defaultMetricsPath,
"A path under which to expose metrics. The default value can be overwritten by TELEMETRY_PATH environment variable.")
nginxPlus = flag.Bool("nginx.plus",
defaultNginxPlus,
"Start the exporter for NGINX Plus. By default, the exporter is started for NGINX. The default value can be overwritten by NGINX_PLUS environment variable.")
scrapeURI = flag.String("nginx.scrape-uri",
defaultScrapeURI,
`A URI or unix domain socket path for scraping NGINX or NGINX Plus metrics.
For NGINX, the stub_status page must be available through the URI. For NGINX Plus -- the API. The default value can be overwritten by SCRAPE_URI environment variable.`)
sslVerify = flag.Bool("nginx.ssl-verify",
defaultSslVerify,
"Perform SSL certificate verification. The default value can be overwritten by SSL_VERIFY environment variable.")
sslCaCert = flag.String("nginx.ssl-ca-cert",
defaultSslCaCert,
"Path to the PEM encoded CA certificate file used to validate the servers SSL certificate. The default value can be overwritten by SSL_CA_CERT environment variable.")
sslClientCert = flag.String("nginx.ssl-client-cert",
defaultSslClientCert,
"Path to the PEM encoded client certificate file to use when connecting to the server. The default value can be overwritten by SSL_CLIENT_CERT environment variable.")
sslClientKey = flag.String("nginx.ssl-client-key",
defaultSslClientKey,
"Path to the PEM encoded client certificate key file to use when connecting to the server. The default value can be overwritten by SSL_CLIENT_KEY environment variable.")
nginxRetries = flag.Uint("nginx.retries",
defaultNginxRetries,
"A number of retries the exporter will make on start to connect to the NGINX stub_status page/NGINX Plus API before exiting with an error. The default value can be overwritten by NGINX_RETRIES environment variable.")
// Custom command-line flags
timeout = createPositiveDurationFlag("nginx.timeout",
defaultTimeout,
"A timeout for scraping metrics from NGINX or NGINX Plus. The default value can be overwritten by TIMEOUT environment variable.")
nginxRetryInterval = createPositiveDurationFlag("nginx.retry-interval",
defaultNginxRetryInterval,
"An interval between retries to connect to the NGINX stub_status page/NGINX Plus API on start. The default value can be overwritten by NGINX_RETRY_INTERVAL environment variable.")
constLabels = createConstLabelsFlag("prometheus.const-labels",
defaultConstLabels,
"A comma separated list of constant labels that will be used in every metric. Format is label1=value1,label2=value2... The default value can be overwritten by CONST_LABELS environment variable.")
)
func main() {
flag.Parse()
log.Printf("Starting NGINX Prometheus Exporter Version=%v GitCommit=%v", version, gitCommit)
registry := prometheus.NewRegistry()
buildInfoMetric := prometheus.NewGauge(
prometheus.GaugeOpts{
Name: "nginxexporter_build_info",
Help: "Exporter build information",
ConstLabels: collector.MergeLabels(
constLabels.labels,
prometheus.Labels{
"version": version,
"gitCommit": gitCommit,
},
),
},
)
buildInfoMetric.Set(1)
registry.MustRegister(buildInfoMetric)
sslConfig := &tls.Config{InsecureSkipVerify: !*sslVerify}
if *sslCaCert != "" {
caCert, err := ioutil.ReadFile(*sslCaCert)
if err != nil {
log.Fatalf("Loading CA cert failed: %v", err)
}
sslCaCertPool := x509.NewCertPool()
ok := sslCaCertPool.AppendCertsFromPEM(caCert)
if !ok {
log.Fatal("Parsing CA cert file failed.")
}
sslConfig.RootCAs = sslCaCertPool
}
if *sslClientCert != "" && *sslClientKey != "" {
clientCert, err := tls.LoadX509KeyPair(*sslClientCert, *sslClientKey)
if err != nil {
log.Fatalf("Loading client certificate failed: %v", err)
}
sslConfig.Certificates = []tls.Certificate{clientCert}
}
transport := &http.Transport{
TLSClientConfig: sslConfig,
}
if strings.HasPrefix(*scrapeURI, "unix:") {
socketPath, requestPath, err := parseUnixSocketAddress(*scrapeURI)
if err != nil {
log.Fatalf("Parsing unix domain socket scrape address %s failed: %v", *scrapeURI, err)
}
transport.DialContext = func(_ context.Context, _, _ string) (net.Conn, error) {
return net.Dial("unix", socketPath)
}
newScrapeURI := "http://unix" + requestPath
scrapeURI = &newScrapeURI
}
userAgent := fmt.Sprintf("NGINX-Prometheus-Exporter/v%v", version)
userAgentRT := &userAgentRoundTripper{
agent: userAgent,
rt: transport,
}
httpClient := &http.Client{
Timeout: timeout.Duration,
Transport: userAgentRT,
}
srv := http.Server{}
signalChan := make(chan os.Signal, 1)
signal.Notify(signalChan, os.Interrupt, syscall.SIGTERM)
go func() {
log.Printf("Signal received: %v. Exiting...", <-signalChan)
err := srv.Close()
if err != nil {
log.Fatalf("Error occurred while closing the server: %v", err)
}
os.Exit(0)
}()
if *nginxPlus {
plusClient, err := createClientWithRetries(func() (interface{}, error) {
return plusclient.NewNginxClient(httpClient, *scrapeURI)
}, *nginxRetries, nginxRetryInterval.Duration)
if err != nil {
log.Fatalf("Could not create Nginx Plus Client: %v", err)
}
registry.MustRegister(collector.NewNginxPlusCollector(plusClient.(*plusclient.NginxClient), "nginxplus", constLabels.labels))
} else {
ossClient, err := createClientWithRetries(func() (interface{}, error) {
return client.NewNginxClient(httpClient, *scrapeURI)
}, *nginxRetries, nginxRetryInterval.Duration)
if err != nil {
log.Fatalf("Could not create Nginx Client: %v", err)
}
registry.MustRegister(collector.NewNginxCollector(ossClient.(*client.NginxClient), "nginx", constLabels.labels))
}
http.Handle(*metricsPath, promhttp.HandlerFor(registry, promhttp.HandlerOpts{}))
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
_, err := fmt.Fprintf(w, `<!DOCTYPE html>
<title>NGINX Exporter</title>
<h1>NGINX Exporter</h1>
<p><a href=%q>Metrics</a></p>`,
*metricsPath)
if err != nil {
log.Printf("Error while sending a response for the '/' path: %v", err)
}
})
listener, err := getListener(*listenAddr)
if err != nil {
log.Fatalf("Could not create listener: %v", err)
}
log.Printf("NGINX Prometheus Exporter has successfully started")
log.Fatal(srv.Serve(listener))
}
type userAgentRoundTripper struct {
agent string
rt http.RoundTripper
}
func (rt *userAgentRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
req = cloneRequest(req)
req.Header.Set("User-Agent", rt.agent)
return rt.rt.RoundTrip(req)
}
func cloneRequest(req *http.Request) *http.Request {
r := new(http.Request)
*r = *req // shallow clone
// deep copy headers
r.Header = make(http.Header, len(req.Header))
for key, values := range req.Header {
newValues := make([]string, len(values))
copy(newValues, values)
r.Header[key] = newValues
}
return r
}