| // Copyright 2017 Google Inc. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| // This file supports generating unique IDs so that multiple test executions |
| // don't interfere with each other, and cleaning up old entities that may |
| // remain if tests exit early. |
| |
| package testutil |
| |
| import ( |
| "fmt" |
| "regexp" |
| "strconv" |
| "sync" |
| "time" |
| ) |
| |
| var startTime = time.Now().UTC() |
| |
| // A UIDSpace manages a set of unique IDs distinguished by a prefix. |
| type UIDSpace struct { |
| Prefix string |
| Sep rune |
| re *regexp.Regexp |
| mu sync.Mutex |
| count int |
| } |
| |
| func NewUIDSpace(prefix string) *UIDSpace { |
| return NewUIDSpaceSep(prefix, '-') |
| } |
| |
| func NewUIDSpaceSep(prefix string, sep rune) *UIDSpace { |
| re := fmt.Sprintf(`^%s%[2]c(\d{4})(\d{2})(\d{2})%[2]c(\d+)%[2]c\d+$`, |
| regexp.QuoteMeta(prefix), sep) |
| return &UIDSpace{ |
| Prefix: prefix, |
| Sep: sep, |
| re: regexp.MustCompile(re), |
| } |
| } |
| |
| // New generates a new unique ID . The ID consists of the UIDSpace's prefix, a |
| // timestamp, and a counter value. All unique IDs generated in the same test |
| // execution will have the same timestamp. |
| // |
| // Aside from the characters in the prefix, IDs contain only letters, numbers |
| // and sep. |
| func (s *UIDSpace) New() string { return s.newID(startTime) } |
| |
| func (s *UIDSpace) newID(t time.Time) string { |
| s.mu.Lock() |
| c := s.count |
| s.count++ |
| s.mu.Unlock() |
| // Write the time as a date followed by nanoseconds from midnight of that date. |
| // That makes it easier to see the approximate time of the ID when it is displayed. |
| y, m, d := t.Date() |
| ns := t.Sub(time.Date(y, m, d, 0, 0, 0, 0, time.UTC)) |
| // Zero-pad the counter for lexical sort order for IDs with the same timestamp. |
| return fmt.Sprintf("%s%c%04d%02d%02d%c%d%c%04d", |
| s.Prefix, s.Sep, y, m, d, s.Sep, ns, s.Sep, c) |
| } |
| |
| // Timestamp extracts the timestamp of uid, which must have been generated by |
| // s. The second return value is true on success, false if there was a problem. |
| func (s *UIDSpace) Timestamp(uid string) (time.Time, bool) { |
| subs := s.re.FindStringSubmatch(uid) |
| if subs == nil { |
| return time.Time{}, false |
| } |
| y, err1 := strconv.Atoi(subs[1]) |
| m, err2 := strconv.Atoi(subs[2]) |
| d, err3 := strconv.Atoi(subs[3]) |
| ns, err4 := strconv.Atoi(subs[4]) |
| if err1 != nil || err2 != nil || err3 != nil || err4 != nil { |
| return time.Time{}, false |
| } |
| return time.Date(y, time.Month(m), d, 0, 0, 0, ns, time.UTC), true |
| } |
| |
| // Older reports whether uid was created by m and has a timestamp older than |
| // the current time by at least d. |
| func (s *UIDSpace) Older(uid string, d time.Duration) bool { |
| ts, ok := s.Timestamp(uid) |
| if !ok { |
| return false |
| } |
| return time.Since(ts) > d |
| } |