func main()

in main.go [58:128]
60 lines of code
10 McCabe index (conditional complexity)

func main() {
	kingpin.Parse()

	log.SetLevel(log.InfoLevel)
	if *debug {
		log.SetLevel(log.DebugLevel)
	}

	sessionConfig := aws.Config{}
	if v := os.Getenv("AWS_STS_REGIONAL_ENDPOINTS"); len(v) == 0 {
		sessionConfig.STSRegionalEndpoint = endpoints.RegionalSTSEndpoint
	}

	session, err := session.NewSession(&sessionConfig)
	if err != nil {
		log.Fatal(err)
	}

	if *regionOverride != "" {
		session.Config.Region = regionOverride
	}

	// For STS regional endpoint to be effective config's region must be set.
	if *session.Config.Region == "" {
		defaultRegion := "us-east-1"
		session.Config.Region = &defaultRegion
	}

	if *disableSSLVerification {
		log.Warn("Peer SSL Certificate validation is DISABLED")
		http.DefaultTransport.(*http.Transport).TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
	}

	var credentials *credentials.Credentials
	if *roleArn != "" {
		credentials = stscreds.NewCredentials(session, *roleArn, func(p *stscreds.AssumeRoleProvider) {
			p.RoleSessionName = roleSessionName()
		})
	} else {
		credentials = session.Config.Credentials
	}

	signer := v4.NewSigner(credentials, func(s *v4.Signer) {
		if *logSinging || *debug {
			s.Logger = awsLoggerAdapter{}
			s.Debug = aws.LogDebugWithSigning
		}
	})
	client := &http.Client{
		CheckRedirect: func(req *http.Request, via []*http.Request) error {
			return http.ErrUseLastResponse
		},
	}

	log.WithFields(log.Fields{"StripHeaders": *strip}).Infof("Stripping headers %s", *strip)
	log.WithFields(log.Fields{"port": *port}).Infof("Listening on %s", *port)

	log.Fatal(
		http.ListenAndServe(*port, &handler.Handler{
			ProxyClient: &handler.ProxyClient{
				Signer:              signer,
				Client:              client,
				StripRequestHeaders: *strip,
				SigningNameOverride: *signingNameOverride,
				HostOverride:        *hostOverride,
				RegionOverride:      *regionOverride,
				LogFailedRequest:    *logFailedResponse,
			},
		}),
	)
}