Added minimal-responses plugin (#4417)
* Added minimal-responses plugin Signed-off-by: Soumya Ghosh Dastidar <gdsoumya@gmail.com> * Removed unnecessary comments * Updated tests Signed-off-by: Soumya Ghosh Dastidar <gdsoumya@gmail.com> * Reformated imports Signed-off-by: Soumya Ghosh Dastidar <gdsoumya@gmail.com> * Updated package name Signed-off-by: Soumya Ghosh Dastidar <gdsoumya@gmail.com> * Removed unnecessary comments Co-authored-by: Miek Gieben <miek@miek.nl> * Added changes Signed-off-by: Soumya Ghosh Dastidar <gdsoumya@gmail.com> * updated Signed-off-by: Soumya Ghosh Dastidar <gdsoumya@gmail.com> * Updated comment for NextOrFailure Signed-off-by: Soumya Ghosh Dastidar <gdsoumya@gmail.com> * Updated to test.Case for testing Signed-off-by: Soumya Ghosh Dastidar <gdsoumya@gmail.com> * Formated imports using goimports Signed-off-by: Soumya Ghosh Dastidar <gdsoumya@gmail.com> Co-authored-by: Miek Gieben <miek@miek.nl>
This commit is contained in:
Soumya Ghosh Dastidar
GitHub
parent
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commit
7651e6c4de
9 changed files with 289 additions and 1 deletions
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@ -37,6 +37,7 @@ var Directives = []string{
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"rewrite",
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"dnssec",
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"autopath",
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"minimal",
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"template",
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"transfer",
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"hosts",
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@ -36,6 +36,7 @@ import (
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_ "github.com/coredns/coredns/plugin/loop"
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_ "github.com/coredns/coredns/plugin/metadata"
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_ "github.com/coredns/coredns/plugin/metrics"
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_ "github.com/coredns/coredns/plugin/minimal"
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_ "github.com/coredns/coredns/plugin/nsid"
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_ "github.com/coredns/coredns/plugin/pprof"
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_ "github.com/coredns/coredns/plugin/ready"
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@ -46,6 +46,7 @@ cache:cache
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rewrite:rewrite
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dnssec:dnssec
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autopath:autopath
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minimal:minimal
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template:template
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transfer:transfer
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hosts:hosts
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36
plugin/minimal/README.md
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36
plugin/minimal/README.md
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@ -0,0 +1,36 @@
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# minimal
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## Name
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*minimal* - minimizes size of the DNS response message whenever possible.
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## Description
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The *minimal* plugin tries to minimize the size of the response. Depending on the response type it
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removes resource records from the AUTHORITY and ADDITIONAL sections.
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Specifically this plugin looks at successful responses (this excludes negative responses, i.e.
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nodata or name error). If the successful response isn't a delegation only the RRs in the answer
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section are written to the client.
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## Syntax
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~~~ txt
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minimal
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~~~
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## Examples
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Enable minimal responses:
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~~~ corefile
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example.org {
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whoami
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forward . 8.8.8.8
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minimal
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}
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~~~
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## See Also
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[BIND 9 Configuration Reference](https://bind9.readthedocs.io/en/latest/reference.html#boolean-options)
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54
plugin/minimal/minimal.go
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54
plugin/minimal/minimal.go
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@ -0,0 +1,54 @@
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package minimal
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import (
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"context"
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"fmt"
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"time"
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"github.com/coredns/coredns/plugin"
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"github.com/coredns/coredns/plugin/pkg/nonwriter"
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"github.com/coredns/coredns/plugin/pkg/response"
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"github.com/miekg/dns"
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)
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// minimalHandler implements the plugin.Handler interface.
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type minimalHandler struct {
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Next plugin.Handler
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}
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func (m *minimalHandler) Name() string { return "minimal" }
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func (m *minimalHandler) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
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nw := nonwriter.New(w)
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rcode, err := plugin.NextOrFailure(m.Name(), m.Next, ctx, nw, r)
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if err != nil {
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return rcode, err
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}
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ty, _ := response.Typify(nw.Msg, time.Now().UTC())
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cl := response.Classify(ty)
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// if response is Denial or Error pass through also if the type is Delegation pass through
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if cl == response.Denial || cl == response.Error || ty == response.Delegation {
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w.WriteMsg(nw.Msg)
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return 0, nil
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}
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if ty != response.NoError {
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w.WriteMsg(nw.Msg)
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return 0, plugin.Error("minimal", fmt.Errorf("unhandled response type %q for %q", ty, nw.Msg.Question[0].Name))
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}
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// copy over the original Msg params, deep copy not required as RRs are not modified
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d := &dns.Msg{
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MsgHdr: nw.Msg.MsgHdr,
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Compress: nw.Msg.Compress,
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Question: nw.Msg.Question,
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Answer: nw.Msg.Answer,
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Ns: nil,
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Extra: nil,
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}
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w.WriteMsg(d)
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return 0, nil
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}
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152
plugin/minimal/minimal_test.go
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152
plugin/minimal/minimal_test.go
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@ -0,0 +1,152 @@
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package minimal
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import (
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"context"
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"testing"
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"github.com/coredns/coredns/plugin"
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"github.com/coredns/coredns/plugin/pkg/dnstest"
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"github.com/coredns/coredns/plugin/test"
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"github.com/miekg/dns"
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)
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// testHandler implements plugin.Handler and will be used to create a stub handler for the test
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type testHandler struct {
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Response *test.Case
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Next plugin.Handler
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}
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func (t *testHandler) Name() string { return "test-handler" }
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func (t *testHandler) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
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d := new(dns.Msg)
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d.SetReply(r)
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if t.Response != nil {
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d.Answer = t.Response.Answer
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d.Ns = t.Response.Ns
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d.Extra = t.Response.Extra
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d.Rcode = t.Response.Rcode
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}
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w.WriteMsg(d)
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return 0, nil
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}
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func TestMinimizeResponse(t *testing.T) {
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baseAnswer := []dns.RR{
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test.A("example.com. 293 IN A 142.250.76.46"),
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}
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baseNs := []dns.RR{
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test.NS("example.com. 157127 IN NS ns2.example.com."),
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test.NS("example.com. 157127 IN NS ns1.example.com."),
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test.NS("example.com. 157127 IN NS ns3.example.com."),
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test.NS("example.com. 157127 IN NS ns4.example.com."),
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}
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baseExtra := []dns.RR{
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test.A("ns2.example.com. 316273 IN A 216.239.34.10"),
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test.AAAA("ns2.example.com. 157127 IN AAAA 2001:4860:4802:34::a"),
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test.A("ns3.example.com. 316274 IN A 216.239.36.10"),
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test.AAAA("ns3.example.com. 157127 IN AAAA 2001:4860:4802:36::a"),
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test.A("ns1.example.com. 165555 IN A 216.239.32.10"),
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test.AAAA("ns1.example.com. 165555 IN AAAA 2001:4860:4802:32::a"),
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test.A("ns4.example.com. 190188 IN A 216.239.38.10"),
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test.AAAA("ns4.example.com. 157127 IN AAAA 2001:4860:4802:38::a"),
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}
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tests := []struct {
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active bool
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original test.Case
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minimal test.Case
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}{
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{ // minimization possible NoError case
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original: test.Case{
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Answer: baseAnswer,
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Ns: nil,
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Extra: baseExtra,
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Rcode: 0,
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},
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minimal: test.Case{
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Answer: baseAnswer,
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Ns: nil,
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Extra: nil,
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Rcode: 0,
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},
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},
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{ // delegate response case
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original: test.Case{
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Answer: nil,
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Ns: baseNs,
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Extra: baseExtra,
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Rcode: 0,
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},
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minimal: test.Case{
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Answer: nil,
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Ns: baseNs,
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Extra: baseExtra,
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Rcode: 0,
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},
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}, { // negative response case
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original: test.Case{
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Answer: baseAnswer,
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Ns: baseNs,
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Extra: baseExtra,
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Rcode: 2,
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},
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minimal: test.Case{
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Answer: baseAnswer,
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Ns: baseNs,
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Extra: baseExtra,
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Rcode: 2,
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},
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},
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}
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for i, tc := range tests {
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req := new(dns.Msg)
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req.SetQuestion("example.com", dns.TypeA)
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tHandler := &testHandler{
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Response: &tc.original,
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Next: nil,
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}
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o := &minimalHandler{Next: tHandler}
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rec := dnstest.NewRecorder(&test.ResponseWriter{})
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_, err := o.ServeDNS(context.TODO(), rec, req)
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if err != nil {
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t.Errorf("Expected no error, but got %q", err)
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}
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if len(tc.minimal.Answer) != len(rec.Msg.Answer) {
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t.Errorf("Test %d: Expected %d Answer, but got %d", i, len(tc.minimal.Answer), len(req.Answer))
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continue
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}
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if len(tc.minimal.Ns) != len(rec.Msg.Ns) {
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t.Errorf("Test %d: Expected %d Ns, but got %d", i, len(tc.minimal.Ns), len(req.Ns))
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continue
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}
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if len(tc.minimal.Extra) != len(rec.Msg.Extra) {
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t.Errorf("Test %d: Expected %d Extras, but got %d", i, len(tc.minimal.Extra), len(req.Extra))
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continue
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}
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for j, a := range rec.Msg.Answer {
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if tc.minimal.Answer[j].String() != a.String() {
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t.Errorf("Test %d: Expected Answer %d to be %v, but got %v", i, j, tc.minimal.Answer[j], a)
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}
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}
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for j, a := range rec.Msg.Ns {
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if tc.minimal.Ns[j].String() != a.String() {
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t.Errorf("Test %d: Expected NS %d to be %v, but got %v", i, j, tc.minimal.Ns[j], a)
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}
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}
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for j, a := range rec.Msg.Extra {
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if tc.minimal.Extra[j].String() != a.String() {
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t.Errorf("Test %d: Expected Extra %d to be %v, but got %v", i, j, tc.minimal.Extra[j], a)
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}
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}
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}
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}
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24
plugin/minimal/setup.go
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24
plugin/minimal/setup.go
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@ -0,0 +1,24 @@
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package minimal
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import (
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"github.com/coredns/caddy"
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"github.com/coredns/coredns/core/dnsserver"
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"github.com/coredns/coredns/plugin"
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)
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func init() {
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plugin.Register("minimal", setup)
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}
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func setup(c *caddy.Controller) error {
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c.Next()
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if c.NextArg() {
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return plugin.Error("minimal", c.ArgErr())
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}
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dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
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return &minimalHandler{Next: next}
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})
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return nil
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}
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19
plugin/minimal/setup_test.go
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19
plugin/minimal/setup_test.go
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@ -0,0 +1,19 @@
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package minimal
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import (
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"testing"
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"github.com/coredns/caddy"
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)
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func TestSetup(t *testing.T) {
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c := caddy.NewTestController("dns", `minimal-response`)
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if err := setup(c); err != nil {
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t.Fatalf("Expected no errors, but got: %v", err)
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}
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c = caddy.NewTestController("dns", `minimal-response example.org`)
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if err := setup(c); err == nil {
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t.Fatalf("Expected errors, but got: %v", err)
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}
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}
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@ -69,7 +69,7 @@ func (f HandlerFunc) Name() string { return "handlerfunc" }
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// Error returns err with 'plugin/name: ' prefixed to it.
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func Error(name string, err error) error { return fmt.Errorf("%s/%s: %s", "plugin", name, err) }
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// NextOrFailure calls next.ServeDNS when next is not nil, otherwise it will return, a ServerFailure and a nil error.
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// NextOrFailure calls next.ServeDNS when next is not nil, otherwise it will return, a ServerFailure and a `no next plugin found` error.
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func NextOrFailure(name string, next Handler, ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) { // nolint: golint
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if next != nil {
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if span := ot.SpanFromContext(ctx); span != nil {
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