Make CoreDNS a server type plugin for Caddy (#220)

* Make CoreDNS a server type plugin for Caddy

Remove code we don't need and port all middleware over. Fix all tests
and rework the documentation.

Also make `go generate` build a caddy binary which we then copy into
our directory. This means `go build`-builds remain working as-is.

And new etc instances in each etcd test for better isolation.
Fix more tests and rework test.Server with the newer support Caddy offers.

Fix Makefile to support new mode of operation.

1 files changed, 143 insertions, 0 deletions

diff --git a/middleware/file/setup.go b/middleware/file/setup.go
new file mode 100644
index 000000000..8b44650ee
--- /dev/null
+++ b/middleware/file/setup.go
@@ -0,0 +1,143 @@
+package file
+
+import (
+	"fmt"
+	"net"
+	"os"
+
+	"github.com/miekg/coredns/core/dnsserver"
+	"github.com/miekg/coredns/middleware"
+
+	"github.com/mholt/caddy"
+)
+
+func init() {
+	caddy.RegisterPlugin("file", caddy.Plugin{
+		ServerType: "dns",
+		Action:     setup,
+	})
+}
+
+func setup(c *caddy.Controller) error {
+	zones, err := fileParse(c)
+	if err != nil {
+		return err
+	}
+
+	// Add startup functions to notify the master(s).
+	for _, n := range zones.Names {
+		c.OnStartup(func() error {
+			zones.Z[n].StartupOnce.Do(func() {
+				if len(zones.Z[n].TransferTo) > 0 {
+					zones.Z[n].Notify()
+				}
+				zones.Z[n].Reload(nil)
+			})
+			return nil
+		})
+	}
+
+	dnsserver.GetConfig(c).AddMiddleware(func(next dnsserver.Handler) dnsserver.Handler {
+		return File{Next: next, Zones: zones}
+	})
+
+	return nil
+}
+
+func fileParse(c *caddy.Controller) (Zones, error) {
+	z := make(map[string]*Zone)
+	names := []string{}
+	origins := []string{}
+
+	for c.Next() {
+		if c.Val() == "file" {
+			// file db.file [zones...]
+			if !c.NextArg() {
+				return Zones{}, c.ArgErr()
+			}
+			fileName := c.Val()
+
+			origins = make([]string, len(c.ServerBlockKeys))
+			copy(origins, c.ServerBlockKeys)
+			args := c.RemainingArgs()
+			if len(args) > 0 {
+				origins = args
+			}
+
+			reader, err := os.Open(fileName)
+			if err != nil {
+				// bail out
+				return Zones{}, err
+			}
+
+			for i, _ := range origins {
+				origins[i] = middleware.Host(origins[i]).Normalize()
+				zone, err := Parse(reader, origins[i], fileName)
+				if err == nil {
+					z[origins[i]] = zone
+				} else {
+					return Zones{}, err
+				}
+				names = append(names, origins[i])
+			}
+
+			noReload := false
+			for c.NextBlock() {
+				t, _, e := TransferParse(c)
+				if e != nil {
+					return Zones{}, e
+				}
+				switch c.Val() {
+				case "no_reload":
+					noReload = true
+				}
+				// discard from, here, maybe check and show log when we do?
+				for _, origin := range origins {
+					if t != nil {
+						z[origin].TransferTo = append(z[origin].TransferTo, t...)
+					}
+					z[origin].NoReload = noReload
+				}
+			}
+		}
+	}
+	return Zones{Z: z, Names: names}, nil
+}
+
+// TransferParse parses transfer statements: 'transfer to [address...]'.
+// Exported so secondary can use this as well.
+func TransferParse(c *caddy.Controller) (tos, froms []string, err error) {
+	what := c.Val()
+	if !c.NextArg() {
+		return nil, nil, c.ArgErr()
+	}
+	value := c.Val()
+	switch what {
+	case "transfer":
+		if value == "to" {
+			tos = c.RemainingArgs()
+			for i, _ := range tos {
+				if tos[i] != "*" {
+					if x := net.ParseIP(tos[i]); x == nil {
+						return nil, nil, fmt.Errorf("must specify an IP addres: `%s'", tos[i])
+					}
+					tos[i] = middleware.Addr(tos[i]).Normalize()
+				}
+			}
+		}
+		if value == "from" {
+			froms = c.RemainingArgs()
+			for i, _ := range froms {
+				if froms[i] != "*" {
+					if x := net.ParseIP(froms[i]); x == nil {
+						return nil, nil, fmt.Errorf("must specify an IP addres: `%s'", froms[i])
+					}
+					froms[i] = middleware.Addr(froms[i]).Normalize()
+				} else {
+					return nil, nil, fmt.Errorf("can't use '*' in transfer from")
+				}
+			}
+		}
+	}
+	return
+}