proxy

type Balancer interface {
	Next(*zinc.Context) (*Target, error)
}

type Config struct {
	// Target is one absolute upstream URL.
	Target   string
	Targets  []*Target
	Balancer Balancer
	// Director runs after hop-by-hop and inbound forwarding headers are removed.
	Director       func(*http.Request)
	ModifyResponse func(*http.Response) error
	ErrorHandler   func(http.ResponseWriter, *http.Request, error)
	Retries        int
	RetryFilter    func(*zinc.Context, error) bool
	// Rewrite maps an upstream path, after the target's own path is added,
	// to the path to send instead. A path ending in "*" matches a prefix,
	// and a "*" in the target is replaced by the rest of the path. When
	// several rules match, an exact rule wins over every "*" rule, and among
	// "*" rules the longest prefix wins. The order is fixed when New runs.
	Rewrite map[string]string
	// RegexRewrite holds regular-expression path rules, tried when no
	// Rewrite rule matches; the target may use $1-style references. A map
	// has no order, so New puts the rules in one: the longest pattern
	// source is tried first, then patterns in lexical order, and the first
	// match wins. New panics when two rules have the same pattern source.
	RegexRewrite map[*regexp.Regexp]string
	Transport    http.RoundTripper
}

type Target struct {
	Name string
	URL  *url.URL
}