Dynamically set reverse_proxy upstreams from custom module

Plugins
8

In this case, the users will be mostly internal - so supporting lots of configs would not make sense in this case as it will be shipped in a Docker image for internal use.

Here is the example ServeHTTP with the Proxy:

type Proxy struct {
	API           string                `json:"api,omitempty"`
	Token         string                `json:"token,omitempty"`

	log *zap.Logger
}

func (p Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
	client, err := consulapi.NewDefaultClient()
	if err != nil {
		p.log.Error("unable to create a new client", zap.Error(err))

		return err
	}

	services, err := client.FindService(r.Host)
	if err != nil {
		p.log.Error("unable to find the service from consul", zap.Error(err), zap.String("service", r.Host))
		return err
	}

	var placeholder string
	for i, s := range services {
        // only working with the first service for now
		if i == 0 {
			a := fmt.Sprintf("http://%s:%d", s.TaggedAddresses.LanIpv4.Address, s.TaggedAddresses.LanIpv4.Port)

			placeholder = a
		}
	}

	caddyhttp.SetVar(r.Context(), "http.consul_proxy.actual_upstream", placeholder)

	if err := next.ServeHTTP(w, r); err != nil {
		p.log.Error("error passing to next handler", zap.Error(err))

		return fmt.Errorf("error passing to next handler. %w", err)
	}

	return nil
}

If I switch the var to http.vars.proxy_upstream I should just be able to return ServeHTTP correct?