Support detailed TLS config for connecting to InfluxDB

CHANGELOG.md

@@ -74,6 +74,7 @@ With #144 you can now join streams with differing group by dimensions.
 - [#249](https://github.com/influxdata/kapacitor/issues/249): Can now use InfluxQL functions directly instead of via the MapReduce method. Example `stream.from().count()`.
 - [#233](https://github.com/influxdata/kapacitor/issues/233): BREAKING: Now you can use multiple InfluxDB clusters. The config changes to make this possible are breaking. See notes above for changes.
 - [#302](https://github.com/influxdata/kapacitor/issues/302): Can now use .Time in alert message.
+- [#239](https://github.com/influxdata/kapacitor/issues/239): Support more detailed TLS config when connecting to an InfluxDB host.
 
 
 ### Bugfixes

etc/kapacitor/kapacitor.conf

@@ -65,6 +65,17 @@ data_dir = "/var/lib/kapacitor"
   username = ""
   password = ""
   timeout = 0
+  # Absolute path to pem encoded CA file.
+  # A CA can be provided without a key/cert pair
+  #   ssl-ca = "/etc/kapacitor/ca.pem"
+  # Absolutes paths to pem encoded key and cert files.
+  #   ssl-cert = "/etc/kapacitor/cert.pem"
+  #   ssl-key = "/etc/kapacitor/key.pem"
+
+  # Do not verify the TLS/SSL certificate.
+  # This is insecure.
+  insecure-skip-verify = false
+
   # Subscriptions use the UDP network protocl.
   # The following options of for the created UDP listeners for each subscription.
   # Number of packets to buffer when reading packets off the socket.

services/influxdb/config.go

@@ -16,12 +16,21 @@ const (
 )
 
 type Config struct {
-	Enabled               bool                `toml:"enabled"`
-	Name                  string              `toml:"name"`
-	Default               bool                `toml:"default"`
-	URLs                  []string            `toml:"urls"`
-	Username              string              `toml:"username"`
-	Password              string              `toml:"password"`
+	Enabled  bool     `toml:"enabled"`
+	Name     string   `toml:"name"`
+	Default  bool     `toml:"default"`
+	URLs     []string `toml:"urls"`
+	Username string   `toml:"username"`
+	Password string   `toml:"password"`
+	// Path to CA file
+	SSLCA string `toml:"ssl-ca"`
+	// Path to host cert file
+	SSLCert string `toml:"ssl-cert"`
+	// Path to cert key file
+	SSLKey string `toml:"ssl-key"`
+	// Use SSL but skip chain & host verification
+	InsecureSkipVerify bool `toml:"insecure-skip-verify"`
+
 	Timeout               toml.Duration       `toml:"timeout"`
 	Subscriptions         map[string][]string `toml:"subscriptions"`
 	ExcludedSubscriptions map[string][]string `toml:"excluded-subscriptions"`
@@ -59,6 +68,10 @@ func (c Config) Validate() error {
 		if err != nil {
 			return err
 		}
+		_, err = getTLSConfig(c.SSLCA, c.SSLCert, c.SSLKey, c.InsecureSkipVerify)
+		if err != nil {
+			return err
+		}
 	}
 	return nil
 }

services/influxdb/service.go

@@ -2,7 +2,11 @@ package influxdb
 
 import (
 	"bytes"
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
 	"fmt"
+	"io/ioutil"
 	"log"
 	"net"
 	"net/url"
@@ -43,13 +47,22 @@ func NewService(configs []Config, defaultInfluxDB int, hostname string, l *log.L
 	var defaultInfluxDBName string
 	for i, c := range configs {
 		urls := make([]client.HTTPConfig, len(c.URLs))
+		tlsConfig, err := getTLSConfig(c.SSLCA, c.SSLCert, c.SSLKey, c.InsecureSkipVerify)
+		if err != nil {
+			// Config should have been validated already
+			panic(err)
+		}
+		if c.InsecureSkipVerify {
+			l.Printf("W! Using InsecureSkipVerify when connecting to InfluxDB @ %v this is insecure!", c.URLs)
+		}
 		for i, u := range c.URLs {
 			urls[i] = client.HTTPConfig{
 				Addr:      u,
 				Username:  c.Username,
 				Password:  c.Password,
 				UserAgent: "Kapacitor",
 				Timeout:   time.Duration(c.Timeout),
+				TLSConfig: tlsConfig,
 			}
 		}
 		subs := make(map[subEntry]bool, len(c.Subscriptions))
@@ -445,3 +458,42 @@ func (s *influxdb) execQuery(cli client.Client, q string) (*client.Response, err
 	}
 	return resp, nil
 }
+
+// getTLSConfig creates a tls.Config object from the given certs, key, and CA files.
+// you must give the full path to the files.
+func getTLSConfig(
+	SSLCA, SSLCert, SSLKey string,
+	InsecureSkipVerify bool,
+) (*tls.Config, error) {
+	t := &tls.Config{
+		InsecureSkipVerify: InsecureSkipVerify,
+	}
+	if SSLCert != "" && SSLKey != "" {
+		cert, err := tls.LoadX509KeyPair(SSLCert, SSLKey)
+		log.Println(SSLCert, SSLKey)
+
+		if err != nil {
+			return nil, fmt.Errorf(
+				"Could not load TLS client key/certificate: %s",
+				err)
+		}
+
+		t.Certificates = []tls.Certificate{cert}
+	} else if SSLCert != "" {
+		return nil, errors.New("Must provide both key and cert files: only cert file provided.")
+	} else if SSLKey != "" {
+		return nil, errors.New("Must provide both key and cert files: only key file provided.")
+	}
+
+	if SSLCA != "" {
+		caCert, err := ioutil.ReadFile(SSLCA)
+		if err != nil {
+			return nil, fmt.Errorf("Could not load TLS CA: %s",
+				err)
+		}
+		caCertPool := x509.NewCertPool()
+		caCertPool.AppendCertsFromPEM(caCert)
+		t.RootCAs = caCertPool
+	}
+	return t, nil
+}