Normalizing Response Duration in Log Plugin (#1860)

* Current stage of the log files. Test need to be done as well as formatting of times.

* Finished testing. All altered classes test pass along with my additions

* Updated the replacer package to print the units as well. May take out.

* Changed the time units to be within the rules. Fixed the test as well.

* Fixed some tests, updated the readme, fixed the replacer class.

* Updates of standardizing only to seconds in response duration. Need to revert README.

* Reverted readme.

* Added a small test in new replacer.

* Changed replacer to inline the strconv for duration.

plugin/pkg/replacer/replacer.go

@@ -55,7 +55,7 @@ func New(r *dns.Msg, rr *dnstest.Recorder, emptyValue string) Replacer {
 		}
 		rep.replacements["{rcode}"] = rcode
 		rep.replacements["{rsize}"] = strconv.Itoa(rr.Len)
-		rep.replacements["{duration}"] = time.Since(rr.Start).String()
+		rep.replacements["{duration}"] = strconv.FormatFloat(time.Since(rr.Start).Seconds(), 'f', -1, 64) + "s"
 		if rr.Msg != nil {
 			rep.replacements[headerReplacer+"rflags}"] = flagsToString(rr.Msg.MsgHdr)
 		}

plugin/pkg/replacer/replacer_test.go

 package replacer
 
 import (
+	"strings"
 	"testing"
 
 	"github.com/coredns/coredns/plugin/pkg/dnstest"
@@ -30,6 +31,9 @@ func TestNewReplacer(t *testing.T) {
 		if v.replacements["{size}"] != "29" { // size of request
 			t.Errorf("Expected size to be 29, got %q", v.replacements["{size}"])
 		}
+		if !strings.Contains(v.replacements["{duration}"], "s") {
+			t.Errorf("Expected units of time to be in seconds")
+		}
 
 	default:
 		t.Fatal("Return Value from New Replacer expected pass type assertion into a replacer type\n")