Default to upstream to self (#2436)

* Default to upstream to self

This is a backwards incompatible change.

This is a massive (cleanup) PR where we default to resolving external
names by the coredns process itself, instead of directly forwarding them
to some upstream.

This ignores any arguments `upstream` may have had and makes it depend
on proxy/forward configuration in the Corefile. This allows resolved
upstream names to be cached and we have better healthchecking of the
upstreams. It also means there is only one way to resolve names, by
either using the proxy or forward plugin.

The proxy/forward lookup.go functions have been removed. This also
lessen the dependency on proxy, meaning deprecating proxy will become
easier. Some tests have been removed as well, or moved to the top-level
test directory as they now require a full coredns process instead of
just the plugin.

For the etcd plugin, the entire StubZone resolving is *dropped*! This
was a hacky (but working) solution to say the least. If someone cares
deeply it can be brought back (maybe)?

The pkg/upstream is now very small and almost does nothing. Also the
New() function was changed to return a pointer to upstream.Upstream. It
also returns only one parameter, so any stragglers using it will
encounter a compile error.

All documentation has been adapted. This affected the following plugins:
* etcd
* file
* auto
* secondary
* federation
* template
* route53

A followup PR will make any upstream directives with arguments an error,
right now they are ignored.

Signed-off-by: Miek Gieben <miek@miek.nl>

* Fix etcd build - probably still fails unit test

Signed-off-by: Miek Gieben <miek@miek.nl>

* Slightly smarter lookup check in upstream

Signed-off-by: Miek Gieben <miek@miek.nl>

* Compilez

Signed-off-by: Miek Gieben <miek@miek.nl>

1 files changed, 0 insertions, 69 deletions

diff --git a/plugin/forward/forward_test.go b/plugin/forward/forward_test.go
deleted file mode 100644
index dfdde933f..000000000
--- a/plugin/forward/forward_test.go
+++ /dev/null
@@ -1,69 +0,0 @@
-package forward
-
-import (
-	"testing"
-
-	"github.com/coredns/coredns/plugin/pkg/dnstest"
-	"github.com/coredns/coredns/plugin/pkg/transport"
-	"github.com/coredns/coredns/plugin/test"
-	"github.com/coredns/coredns/request"
-
-	"github.com/miekg/dns"
-)
-
-func TestForward(t *testing.T) {
-	s := dnstest.NewServer(func(w dns.ResponseWriter, r *dns.Msg) {
-		ret := new(dns.Msg)
-		ret.SetReply(r)
-		ret.Answer = append(ret.Answer, test.A("example.org. IN A 127.0.0.1"))
-		w.WriteMsg(ret)
-	})
-	defer s.Close()
-
-	p := NewProxy(s.Addr, transport.DNS)
-	f := New()
-	f.SetProxy(p)
-	defer f.Close()
-
-	state := request.Request{W: &test.ResponseWriter{}, Req: new(dns.Msg)}
-	state.Req.SetQuestion("example.org.", dns.TypeA)
-	resp, err := f.Forward(state)
-	if err != nil {
-		t.Fatal("Expected to receive reply, but didn't")
-	}
-	// expect answer section with A record in it
-	if len(resp.Answer) == 0 {
-		t.Fatalf("Expected to at least one RR in the answer section, got none: %s", resp)
-	}
-	if resp.Answer[0].Header().Rrtype != dns.TypeA {
-		t.Errorf("Expected RR to A, got: %d", resp.Answer[0].Header().Rrtype)
-	}
-	if resp.Answer[0].(*dns.A).A.String() != "127.0.0.1" {
-		t.Errorf("Expected 127.0.0.1, got: %s", resp.Answer[0].(*dns.A).A.String())
-	}
-}
-
-func TestForwardRefused(t *testing.T) {
-	s := dnstest.NewServer(func(w dns.ResponseWriter, r *dns.Msg) {
-		ret := new(dns.Msg)
-		ret.SetReply(r)
-		ret.Rcode = dns.RcodeRefused
-		w.WriteMsg(ret)
-	})
-	defer s.Close()
-
-	p := NewProxy(s.Addr, transport.DNS)
-	f := New()
-	f.SetProxy(p)
-	defer f.Close()
-
-	state := request.Request{W: &test.ResponseWriter{}, Req: new(dns.Msg)}
-	state.Req.SetQuestion("example.org.", dns.TypeA)
-	resp, err := f.Forward(state)
-	if err != nil {
-		t.Fatal("Expected to receive reply, but didn't")
-	}
-	if resp.Rcode != dns.RcodeRefused {
-		t.Errorf("Expected rcode to be %d, got %d", dns.RcodeRefused, resp.Rcode)
-	}
-}