Ensure tags use the correct escape codes.

Similar to measurement names, some characters were being escaped
incorrectly.

tsdb/points.go

@@ -96,6 +96,12 @@ var (
 		',': []byte(`\,`),
 		' ': []byte(`\ `),
 	}
+
+	tagEscapeCodes = map[byte][]byte{
+		',': []byte(`\,`),
+		' ': []byte(`\ `),
+		'=': []byte(`\=`),
+	}
 )
 
 func init() {
@@ -846,6 +852,20 @@ func unescapeMeasurement(in []byte) []byte {
 	return in
 }
 
+func escapeTag(in []byte) []byte {
+	for b, esc := range tagEscapeCodes {
+		in = bytes.Replace(in, []byte{b}, esc, -1)
+	}
+	return in
+}
+
+func unescapeTag(in []byte) []byte {
+	for b, esc := range tagEscapeCodes {
+		in = bytes.Replace(in, esc, []byte{b}, -1)
+	}
+	return in
+}
+
 func escape(in []byte) []byte {
 	for b, esc := range escapeCodes {
 		in = bytes.Replace(in, []byte{b}, esc, -1)
@@ -956,7 +976,7 @@ func (p *point) Tags() Tags {
 			i, key = scanTo(p.key, i, '=')
 			i, value = scanTagValue(p.key, i+1)
 
-			tags[string(unescape(key))] = string(unescape(value))
+			tags[string(unescapeTag(key))] = string(unescapeTag(value))
 
 			i += 1
 		}
@@ -1061,9 +1081,9 @@ func (t Tags) HashKey() []byte {
 
 	escaped := Tags{}
 	for k, v := range t {
-		ek := escapeString(k)
-		ev := escapeString(v)
-		escaped[ek] = ev
+		ek := escapeTag([]byte(k))
+		ev := escapeTag([]byte(v))
+		escaped[string(ek)] = string(ev)
 	}
 
 	// Extract keys and determine final size.

tsdb/points_test.go

@@ -758,6 +758,21 @@ func TestParsePointQuotedMeasurement(t *testing.T) {
 	)
 }
 
+func TestParsePointQuotedTags(t *testing.T) {
+	test(t, `cpu,"host"="serverA",region=us-east value=1.0 1000000000`,
+		tsdb.NewPoint(
+			"cpu",
+			tsdb.Tags{
+				`"host"`: `"serverA"`,
+				"region": "us-east",
+			},
+			tsdb.Fields{
+				"value": 1.0,
+			},
+			time.Unix(1, 0)),
+	)
+}
+
 func TestParsePointEscapedStringsAndCommas(t *testing.T) {
 	// non-escaped comma and quotes
 	test(t, `cpu,host=serverA,region=us-east value="{Hello\"{,}\" World}" 1000000000`,