Adding x509_cert input plugin (#3768)

plugins/inputs/x509_cert/x509_cert.go

@@ -0,0 +1,163 @@
+// Package x509_cert reports metrics from an SSL certificate.
+package x509_cert
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/pem"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"net/url"
+	"strings"
+	"time"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/internal"
+	_tls "github.com/influxdata/telegraf/internal/tls"
+	"github.com/influxdata/telegraf/plugins/inputs"
+)
+
+const sampleConfig = `
+  ## List certificate sources
+  sources = ["/etc/ssl/certs/ssl-cert-snakeoil.pem", "tcp://example.org:443"]
+
+  ## Timeout for SSL connection
+  # timeout = 5s
+
+  ## Optional TLS Config
+  # tls_ca = "/etc/telegraf/ca.pem"
+  # tls_cert = "/etc/telegraf/cert.pem"
+  # tls_key = "/etc/telegraf/key.pem"
+
+  ## Use TLS but skip chain & host verification
+  # insecure_skip_verify = false
+`
+const description = "Reads metrics from a SSL certificate"
+
+// X509Cert holds the configuration of the plugin.
+type X509Cert struct {
+	Sources []string          `toml:"sources"`
+	Timeout internal.Duration `toml:"timeout"`
+	_tls.ClientConfig
+}
+
+// Description returns description of the plugin.
+func (c *X509Cert) Description() string {
+	return description
+}
+
+// SampleConfig returns configuration sample for the plugin.
+func (c *X509Cert) SampleConfig() string {
+	return sampleConfig
+}
+
+func (c *X509Cert) getCert(location string, timeout time.Duration) ([]*x509.Certificate, error) {
+	if strings.HasPrefix(location, "/") {
+		location = "file://" + location
+	}
+
+	u, err := url.Parse(location)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse cert location - %s\n", err.Error())
+	}
+
+	switch u.Scheme {
+	case "https":
+		u.Scheme = "tcp"
+		fallthrough
+	case "udp", "udp4", "udp6":
+		fallthrough
+	case "tcp", "tcp4", "tcp6":
+		tlsCfg, err := c.ClientConfig.TLSConfig()
+		if err != nil {
+			return nil, err
+		}
+
+		ipConn, err := net.DialTimeout(u.Scheme, u.Host, timeout)
+		if err != nil {
+			return nil, err
+		}
+		defer ipConn.Close()
+
+		conn := tls.Client(ipConn, tlsCfg)
+		defer conn.Close()
+
+		hsErr := conn.Handshake()
+		if hsErr != nil {
+			return nil, hsErr
+		}
+
+		certs := conn.ConnectionState().PeerCertificates
+
+		return certs, nil
+	case "file":
+		content, err := ioutil.ReadFile(u.Path)
+		if err != nil {
+			return nil, err
+		}
+
+		block, _ := pem.Decode(content)
+		if block == nil {
+			return nil, fmt.Errorf("failed to parse certificate PEM")
+		}
+
+		cert, err := x509.ParseCertificate(block.Bytes)
+		if err != nil {
+			return nil, err
+		}
+
+		return []*x509.Certificate{cert}, nil
+	default:
+		return nil, fmt.Errorf("unsuported scheme '%s' in location %s\n", u.Scheme, location)
+	}
+}
+
+func getFields(cert *x509.Certificate, now time.Time) map[string]interface{} {
+	age := int(now.Sub(cert.NotBefore).Seconds())
+	expiry := int(cert.NotAfter.Sub(now).Seconds())
+	startdate := cert.NotBefore.Unix()
+	enddate := cert.NotAfter.Unix()
+
+	fields := map[string]interface{}{
+		"age":       age,
+		"expiry":    expiry,
+		"startdate": startdate,
+		"enddate":   enddate,
+	}
+
+	return fields
+}
+
+// Gather adds metrics into the accumulator.
+func (c *X509Cert) Gather(acc telegraf.Accumulator) error {
+	now := time.Now()
+
+	for _, location := range c.Sources {
+		certs, err := c.getCert(location, c.Timeout.Duration*time.Second)
+		if err != nil {
+			return fmt.Errorf("cannot get SSL cert '%s': %s", location, err.Error())
+		}
+
+		tags := map[string]string{
+			"source": location,
+		}
+
+		for _, cert := range certs {
+			fields := getFields(cert, now)
+
+			acc.AddFields("x509_cert", fields, tags)
+		}
+	}
+
+	return nil
+}
+
+func init() {
+	inputs.Add("x509_cert", func() telegraf.Input {
+		return &X509Cert{
+			Sources: []string{},
+			Timeout: internal.Duration{Duration: 5},
+		}
+	})
+}