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, 124 deletions

diff --git a/plugin/file/cname_test.go b/plugin/file/cname_test.go
deleted file mode 100644
index 10eb7d934..000000000
--- a/plugin/file/cname_test.go
+++ /dev/null
@@ -1,124 +0,0 @@
-package file
-
-import (
-	"context"
-	"strings"
-	"testing"
-
-	"github.com/coredns/coredns/plugin/pkg/dnstest"
-	"github.com/coredns/coredns/plugin/pkg/upstream"
-	"github.com/coredns/coredns/plugin/test"
-
-	"github.com/miekg/dns"
-)
-
-func TestLookupCNAMEChain(t *testing.T) {
-	name := "example.org."
-	zone, err := Parse(strings.NewReader(dbExampleCNAME), name, "stdin", 0)
-	if err != nil {
-		t.Fatalf("Expected no error when reading zone, got %q", err)
-	}
-
-	fm := File{Next: test.ErrorHandler(), Zones: Zones{Z: map[string]*Zone{name: zone}, Names: []string{name}}}
-	ctx := context.TODO()
-
-	for _, tc := range cnameTestCases {
-		m := tc.Msg()
-
-		rec := dnstest.NewRecorder(&test.ResponseWriter{})
-		_, err := fm.ServeDNS(ctx, rec, m)
-		if err != nil {
-			t.Errorf("Expected no error, got %v\n", err)
-			return
-		}
-
-		resp := rec.Msg
-		test.SortAndCheck(t, resp, tc)
-	}
-}
-
-var cnameTestCases = []test.Case{
-	{
-		Qname: "a.example.org.", Qtype: dns.TypeA,
-		Answer: []dns.RR{
-			test.A("a.example.org. 1800	IN	A 127.0.0.1"),
-		},
-	},
-	{
-		Qname: "www3.example.org.", Qtype: dns.TypeCNAME,
-		Answer: []dns.RR{
-			test.CNAME("www3.example.org. 1800	IN	CNAME www2.example.org."),
-		},
-	},
-	{
-		Qname: "dangling.example.org.", Qtype: dns.TypeA,
-		Answer: []dns.RR{
-			test.CNAME("dangling.example.org. 1800	IN	CNAME foo.example.org."),
-		},
-	},
-	{
-		Qname: "www3.example.org.", Qtype: dns.TypeA,
-		Answer: []dns.RR{
-			test.A("a.example.org. 1800	IN	A 127.0.0.1"),
-			test.CNAME("www.example.org. 1800	IN	CNAME a.example.org."),
-			test.CNAME("www1.example.org. 1800	IN	CNAME www.example.org."),
-			test.CNAME("www2.example.org. 1800	IN	CNAME www1.example.org."),
-			test.CNAME("www3.example.org. 1800	IN	CNAME www2.example.org."),
-		},
-	},
-}
-
-func TestLookupCNAMEExternal(t *testing.T) {
-	name := "example.org."
-	zone, err := Parse(strings.NewReader(dbExampleCNAME), name, "stdin", 0)
-	if err != nil {
-		t.Fatalf("Expected no error when reading zone, got %q", err)
-	}
-	zone.Upstream, _ = upstream.New([]string{"8.8.8.8:53"}) // TODO(miek): point to local instance
-
-	fm := File{Next: test.ErrorHandler(), Zones: Zones{Z: map[string]*Zone{name: zone}, Names: []string{name}}}
-	ctx := context.TODO()
-
-	for _, tc := range exernalTestCases {
-		m := tc.Msg()
-
-		rec := dnstest.NewRecorder(&test.ResponseWriter{})
-		_, err := fm.ServeDNS(ctx, rec, m)
-		if err != nil {
-			t.Errorf("Expected no error, got %v\n", err)
-			return
-		}
-
-		resp := rec.Msg
-		test.SortAndCheck(t, resp, tc)
-	}
-}
-
-var exernalTestCases = []test.Case{
-	{
-		Qname: "external.example.org.", Qtype: dns.TypeA,
-		Answer: []dns.RR{
-			test.CNAME("external.example.org. 1800	CNAME	www.example.net."),
-			// magic 303 TTL that says: don't check TTL.
-			test.A("www.example.net.	303	IN	A	93.184.216.34"),
-		},
-	},
-}
-
-const dbExampleCNAME = `
-$TTL    30M
-$ORIGIN example.org.
-@       IN      SOA     linode.atoom.net. miek.miek.nl. (
-                             1282630057 ; Serial
-                             4H         ; Refresh
-                             1H         ; Retry
-                             7D         ; Expire
-                             4H )       ; Negative Cache TTL
-
-a               IN      A       127.0.0.1
-www3            IN      CNAME   www2
-www2            IN      CNAME   www1
-www1            IN      CNAME   www
-www             IN      CNAME   a
-dangling        IN      CNAME   foo
-external        IN      CNAME   www.example.net.`