Ensure no field value is null

Fix issue #2420.

CHANGELOG.md

@@ -9,6 +9,7 @@
 - [#2415](https://github.com/influxdb/influxdb/pull/2415): Raft leader ID now set on election after failover. Thanks @xiaost
 - [#2426](https://github.com/influxdb/influxdb/pull/2426): Fix race condition around listener address in openTSDB server.
 - [#2426](https://github.com/influxdb/influxdb/pull/2426): Fix race condition around listener address in Graphite server.
+- [#2429](https://github.com/influxdb/influxdb/pull/2429): Ensure no field value is null.
 
 ### Features
 - [#2410](https://github.com/influxdb/influxdb/pull/2410) Allow configuration of Raft timers

httpd/handler_test.go

@@ -1184,6 +1184,26 @@ func TestHandler_serveWriteSeriesWithNoFields(t *testing.T) {
 	}
 }
 
+func TestHandler_serveWriteSeriesWithNullFields(t *testing.T) {
+	c := test.NewDefaultMessagingClient()
+	defer c.Close()
+	srvr := OpenAuthenticatedServer(c)
+	srvr.CreateDatabase("foo")
+	srvr.CreateRetentionPolicy("foo", influxdb.NewRetentionPolicy("bar"))
+	s := NewAPIServer(srvr)
+	defer s.Close()
+
+	status, body := MustHTTP("POST", s.URL+`/write`, nil, nil, `{"database" : "foo", "retentionPolicy" : "bar", "points": [{"name": "cpu", "fields": {"country": null}}]}`)
+
+	expected := fmt.Sprintf(`{"error":"%s"}`, influxdb.ErrFieldIsNull.Error())
+
+	if status != http.StatusInternalServerError {
+		t.Fatalf("unexpected status: %d", status)
+	} else if body != expected {
+		t.Fatalf("result mismatch:\n\texp=%s\n\tgot=%s\n", expected, body)
+	}
+}
+
 func TestHandler_serveWriteSeriesWithAuthNilUser(t *testing.T) {
 	c := test.NewDefaultMessagingClient()
 	defer c.Close()

influxdb.go

@@ -117,6 +117,9 @@ var (
 	// ErrFieldsRequired is returned when a point does not any fields.
 	ErrFieldsRequired = errors.New("fields required")
 
+	// FieldIsNull is returned when one of a point's field is null.
+	ErrFieldIsNull = errors.New("field value is null")
+
 	// ErrFieldOverflow is returned when too many fields are created on a measurement.
 	ErrFieldOverflow = errors.New("field overflow")
 

server.go

@@ -1766,11 +1766,17 @@ func (s *Server) WriteSeries(database, retentionPolicy string, points []Point) (
 			database, retentionPolicy, len(points))
 	}
 
-	// Make sure every point has at least one field.
+	// Make sure every point is valid.
 	for _, p := range points {
 		if len(p.Fields) == 0 {
 			return 0, ErrFieldsRequired
 		}
+
+		for _, f := range p.Fields {
+			if f == nil {
+				return 0, ErrFieldIsNull
+			}
+		}
 	}
 
 	// If the retention policy is not set, use the default for this database.