coredns/middleware/rewrite/setup.go

package rewrite

import (
	"log"

	"github.com/miekg/coredns/core/dnsserver"
	"github.com/miekg/coredns/middleware"

	"github.com/mholt/caddy"
)

func init() {
	caddy.RegisterPlugin("rewrite", caddy.Plugin{
		ServerType: "dns",
		Action:     setup,
	})
}

func setup(c *caddy.Controller) error {
	rewrites, err := rewriteParse(c)
	if err != nil {
		return middleware.Error("rewrite", err)
	}

	dnsserver.GetConfig(c).AddMiddleware(func(next middleware.Handler) middleware.Handler {
		return Rewrite{Next: next, Rules: rewrites}
	})

	return nil
}

func rewriteParse(c *caddy.Controller) ([]Rule, error) {
	var simpleRules []Rule
	var regexpRules []Rule

	for c.Next() {
		var rule Rule
		/*
			var base = "."
			var err error
			var pattern, to string
			var status int
			var ifs []If
			var ext []string
		*/

		args := c.RemainingArgs()

		switch len(args) {
		case 1:
			/*
				base = args[0]
				fallthrough
			*/
		case 0:
			/*
				for c.NextBlock() {
					switch c.Val() {
					case "r", "regexp":
						if !c.NextArg() {
							return nil, c.ArgErr()
						}
						pattern = c.Val()
					case "to":
						args1 := c.RemainingArgs()
						if len(args1) == 0 {
							return nil, c.ArgErr()
						}
						to = strings.Join(args1, " ")
					case "ext": // TODO(miek): fix or remove
						args1 := c.RemainingArgs()
						if len(args1) == 0 {
							return nil, c.ArgErr()
						}
						ext = args1
					case "if":
						args1 := c.RemainingArgs()
						if len(args1) != 3 {
							return nil, c.ArgErr()
						}
						ifCond, err := NewIf(args1[0], args1[1], args1[2])
						if err != nil {
							return nil, err
						}
						ifs = append(ifs, ifCond)
					case "status": // TODO(miek): fix or remove
						if !c.NextArg() {
							return nil, c.ArgErr()
						}
						status, _ = strconv.Atoi(c.Val())
						if status < 200 || (status > 299 && status < 400) || status > 499 {
							return nil, c.Err("status must be 2xx or 4xx")
						}
					default:
						return nil, c.ArgErr()
					}
				}
				// ensure to or status is specified
				if to == "" && status == 0 {
					return nil, c.ArgErr()
				}
				// TODO(miek): complex rules
				if rule, err = NewComplexRule(base, pattern, to, status, ext, ifs); err != nil {
					return nil, err
				}
				regexpRules = append(regexpRules, rule)
			*/

		// the only unhandled case is 2 and above
		default:
			if _, ok := Fields[args[0]]; ok {
				rule = Fields[args[0]].New(args[1:]...)
				simpleRules = append(simpleRules, rule)
			} else {
				log.Printf("[WARN] %s is not a valid field, ignore %s", args[0], args)
			}
		}
	}

	// put simple rules in front to avoid regexp computation for them
	return append(simpleRules, regexpRules...), nil
}