func NewClient()

in internal/proxy/proxy.go [514:563]
42 lines of code
10 McCabe index (conditional complexity)

func NewClient(ctx context.Context, d cloudsql.Dialer, l cloudsql.Logger, conf *Config, connRefuseNotify func()) (*Client, error) {
	// Check if the caller has configured a dialer.
	// Otherwise, initialize a new one.
	if d == nil {
		dialerOpts, err := conf.DialerOptions(l)
		if err != nil {
			return nil, fmt.Errorf("error initializing dialer: %v", err)
		}
		d, err = cloudsqlconn.NewDialer(ctx, dialerOpts...)
		if err != nil {
			return nil, fmt.Errorf("error initializing dialer: %v", err)
		}
	}

	c := &Client{
		logger:           l,
		dialer:           d,
		connRefuseNotify: connRefuseNotify,
		conf:             conf,
	}

	if conf.FUSEDir != "" {
		return configureFUSE(c, conf)
	}

	for _, inst := range conf.Instances {
		// Initiate refresh operation and warm the cache.
		go func(name string) { _, _ = d.EngineVersion(ctx, name) }(inst.Name)
	}

	var mnts []*socketMount
	pc := newPortConfig(conf.Port)
	for _, inst := range conf.Instances {
		m, err := c.newSocketMount(ctx, conf, pc, inst)
		if err != nil {
			for _, m := range mnts {
				mErr := m.Close()
				if mErr != nil {
					l.Errorf("failed to close mount: %v", mErr)
				}
			}
			return nil, fmt.Errorf("[%v] Unable to mount socket: %v", inst.Name, err)
		}

		l.Infof("[%s] Listening on %s", inst.Name, m.Addr())
		mnts = append(mnts, m)
	}
	c.mnts = mnts
	return c, nil
}