Add config option to skip SSL certs checks

This addresses https://github.com/google/alertmanager-irc-relay/issues/3

Signed-off-by: Luca Bigliardi <shammash@google.com>

config.go

@@ -38,6 +38,7 @@ type Config struct {
 	IRCHost      string       `yaml:"irc_host"`
 	IRCPort      int          `yaml:"irc_port"`
 	IRCUseSSL    bool         `yaml:"irc_use_ssl"`
+	IRCVerifySSL bool         `yaml:"irc_verify_ssl"`
 	IRCChannels  []IRCChannel `yaml:"irc_channels"`
 	MsgTemplate  string       `yaml:"msg_template"`
 	MsgOnce      bool         `yaml:"msg_once_per_alert_group"`
@@ -54,6 +55,7 @@ func LoadConfig(configFile string) (*Config, error) {
 		IRCHost:      "irc.freenode.net",
 		IRCPort:      7000,
 		IRCUseSSL:    true,
+		IRCVerifySSL: true,
 		IRCChannels:  []IRCChannel{IRCChannel{Name: "#airtest"}},
 		MsgOnce:      false,
 		UsePrivmsg:   false,

irc.go

@@ -77,7 +77,10 @@ func NewIRCNotifier(config *Config, alertMsgs chan AlertMsg) (*IRCNotifier, erro
 	ircConfig.Server = strings.Join(
 		[]string{config.IRCHost, strconv.Itoa(config.IRCPort)}, ":")
 	ircConfig.SSL = config.IRCUseSSL
-	ircConfig.SSLConfig = &tls.Config{ServerName: config.IRCHost}
+	ircConfig.SSLConfig = &tls.Config{
+		ServerName:         config.IRCHost,
+		InsecureSkipVerify: !config.IRCVerifySSL,
+	}
 	ircConfig.PingFreq = pingFrequencySecs * time.Second
 	ircConfig.Timeout = connectionTimeoutSecs * time.Second
 	ircConfig.NewNick = func(n string) string { return n + "^" }