go-again/again.go

284 lines
8.2 KiB
Go

package again
import (
"fmt"
"time"
webhooks "git.rootprojects.org/root/go-again/webhooks"
)
type Webhook webhooks.Webhook
type Schedule struct {
ID string `json:"id" db:"id"`
AccessID string `json:"-" db:"access_id"`
Date string `json:"date" db:"date"`
Time string `json:"time" db:"time"`
TZ string `json:"tz" db:"tz"`
NextRunAt time.Time `json:"next_run_at" db:"next_run_at"`
Webhooks []Webhook `json:"webhooks" db"webhooks"`
}
type Schedules []*Schedule
func (s Schedules) Len() int {
return len(s)
}
func (s Schedules) Less(i, j int) bool {
return s[i].NextRunAt.Sub(s[j].NextRunAt) < 0
}
func (s Schedules) Swap(i, j int) {
s[j], s[i] = s[i], s[j]
}
// https://yourbasic.org/golang/time-change-convert-location-timezone/
// https://sebest.github.io/post/create-a-small-docker-image-for-a-golang-binary/
// https://github.com/FKSE/docker-golang-base
// tar cfz zoneinfo.tar.gz /usr/share/zoneinfo
// git clone https://github.com/eggert/tz
// grep '^Rule' -r tz/ | cut -f8-10 | egrep -iv 'Rule|SAVE'
// egrep '\s0:30' -r tz/
func Run() {
// blacklist "", "Local"
// UTC to TZ should always be correct
// TZ to UTC may not be correct
now := time.Now()
fmt.Println("Now", now.Format(time.RFC3339))
loc, err := time.LoadLocation("America/Phoenix")
if nil != err {
panic(err)
}
fmt.Println("Loc", now.In(loc))
/* boundary checks */
for _, st := range [][]int{
[]int{2019, 11, 10, 01, 02, 56, 0},
[]int{2019, 11, 10, 01, 02, 60, 0},
[]int{2019, 11, 10, 01, 60, 59, 0},
[]int{2019, 11, 10, 24, 59, 59, 0},
[]int{2019, 11, 10, 25, 59, 59, 0},
[]int{2019, 11, 10, 23, 59, 59, 0},
[]int{2019, 11, 31, 23, 0, 0, 0},
} {
_, err := Exists(st, "America/Denver")
if nil != err {
fmt.Println(err)
}
}
/* funky times */
tz := "America/Denver"
fmt.Println("funky")
for _, st := range [][]int{
[]int{2019, 3, 10, 01, 59, 00, 0},
[]int{2019, 3, 10, 02, 00, 00, 0},
[]int{2019, 3, 10, 02, 01, 00, 0},
[]int{2019, 3, 10, 02, 59, 00, 0},
[]int{2019, 3, 10, 03, 00, 00, 0},
[]int{2019, 3, 10, 03, 01, 00, 0},
[]int{2019, 11, 03, 0, 59, 00, 0},
[]int{2019, 11, 03, 01, 59, 00, 0},
[]int{2019, 11, 03, 02, 00, 00, 0},
[]int{2019, 11, 03, 02, 01, 00, 0},
[]int{2019, 11, 03, 02, 59, 00, 0},
[]int{2019, 11, 03, 03, 00, 00, 0},
[]int{2019, 11, 03, 03, 01, 00, 0},
[]int{2019, 11, 03, 04, 01, 00, 0},
[]int{2019, 11, 03, 05, 01, 00, 0},
} {
err := IsAmbiguous(st, tz)
if nil != err {
fmt.Println(err)
}
}
}
type ErrNoExist struct {
e string
t []int
z string
}
func (err ErrNoExist) Error() string {
return fmt.Sprintf("E_INVALID_TIME: '%#v' is not a valid timestamp at '%s': %s", err.t, err.z, err.e)
}
// Check if the time is a real time in the given timezone.
//
// For example: 2:30am doesn't happen on 2019 March 10th according
// to America/Denver local time, due to the end of Daylight Savings Time,
// but it does happen in America/Phoenix.
//
// Also rejects times that are parsable and return a valid date object,
// but are not canonical, such as 24:60:75 November 31st, 2020.
// (which would be represented as `2020-12-02 02:01:15 +0000 UTC`)
//
// Example of parsable, but non-canonical time:
//
// var loc *time.Location
// loc, _ = time.LoadLocation("America/Denver")
// t := time.Date(2019, time.March, 10, 1, 30, 0, 0, loc)
// fmt.Println(t, "==", t.UTC())
// // 2019-03-10 01:30:00 -0700 MST == 2019-03-10 08:30:00 +0000 UTC
// t = t.Add(time.Duration(1) * time.Hour)
// fmt.Println(t, "==", t.UTC())
// // 2019-03-10 03:30:00 -0600 MDT == 2019-03-10 09:30:00 +0000 UTC
//
// Example of a canonical, but non-parsable time (the 2016 leap second):
//
// fmt.Println(time.Date(2016, time.December, 31, 23, 59, 60, 0, time.UTC))
// "2020-12-02 02:00:00 +0000 UTC" // should be "2016-12-31 23:59:60 +0000 UTC"
//
func Exists(st []int, tzstr string) (*time.Time, error) {
tz, err := time.LoadLocation(tzstr)
if nil != err {
return nil, err
}
m := time.Month(st[1])
t1 := time.Date(st[0], m, st[2], st[3], st[4], st[5], 0, tz)
if st[5] != t1.Second() {
return nil, ErrNoExist{
t: st,
z: tzstr,
e: "invalid second, probably just bad math on your part",
}
}
if st[4] != t1.Minute() {
return nil, ErrNoExist{
t: st,
z: tzstr,
e: "invalid minute, probably just bad math on your part, but perhaps a half-hour daylight savings or summer time",
}
}
if st[3] != t1.Hour() {
return nil, ErrNoExist{
t: st,
z: tzstr,
e: "invalid hour, possibly a Daylight Savings or Summer Time error, or perhaps bad math on your part",
}
}
if st[2] != t1.Day() {
return nil, ErrNoExist{
t: st,
z: tzstr,
e: "invalid day of month, most likely bad math on your part. Remember: 31 28¼ 31 30 31 30 31 31 30 31 30 31",
}
}
if st[1] != int(t1.Month()) {
return nil, ErrNoExist{
t: st,
z: tzstr,
e: "invalid month, most likely bad math on your part. Remember: Decemberween isn't until next year",
}
}
if st[0] != t1.Year() {
return nil, ErrNoExist{
t: st,
z: tzstr,
e: "invalid year, must have reached the end of time...",
}
}
return &t1, nil
}
// Check if the time happens more than once in a given timezone.
//
// For example: 1:30am happens only once on 2019 Nov 3rd according to
// America/Phoenix time but due to the start of Daylight Savings Time,
// it happens twice in America/Denver.
//
// Example of duplicate, non-canonical time:
//
// var loc *time.Location
// loc, _ = time.LoadLocation("America/Denver")
// t = time.Date(2019, time.November, 3, 1, 30, 0, 0, loc)
// fmt.Println(t, "==", t.UTC())
// // 2019-11-03 01:30:00 -0600 MDT == 2019-11-03 07:30:00 +0000 UTC
// t = t.Add(time.Duration(1) * time.Hour)
// fmt.Println(t, "==", t.UTC())
// // 2019-11-03 01:30:00 -0700 MST == 2019-11-03 08:30:00 +0000 UTC
// t = t.Add(time.Duration(1) * time.Hour)
// fmt.Println(t, "==", t.UTC())
// // 2019-11-03 02:30:00 -0700 MST == 2019-11-03 09:30:00 +0000 UTC
//
func IsAmbiguous(st []int, tzstr string) error {
// Does the time exist twice?
// (if I change the time in UTC, do I still get the same time)
// Note: Some timezones change by half or quarter hour
// However, it seems that DST always changes by one or two whole hours
// Oh, and then there's Luthuania...
// Rule LH 2008 max - Oct Sun>=1 2:00 0:30 -
//
// https://en.wikipedia.org/wiki/Daylight_saving_time_by_country
// https://en.wikipedia.org/wiki/Winter_time_(clock_lag)
// https://en.wikipedia.org/wiki/Summer_time_in_Europe
// https://en.wikipedia.org/wiki/Daylight_saving_time_in_the_Americas
// If I change the time iadd or subtract time in UTC, do I see the same difference in TZ?
tz, err := time.LoadLocation(tzstr)
if nil != err {
return err
}
m := time.Month(st[1])
t1 := time.Date(st[0], m, st[2], st[3], st[4], st[5], 0, tz)
u1 := t1.UTC()
// Australia/Lord_Howe has a 30-minute DST
// 60-minute DST is common
// Antarctica/Troll has a 120-minute DST
for _, n := range []int{30, 60, 120} {
t2 := time.Date(st[0], m, st[2], st[3], st[4]+n, st[5], 0, tz)
u2 := t2.UTC()
if u1.Equal(u2) {
return fmt.Errorf("Ambiguous: %s, %s, %+d\n", t1, t2, n)
}
}
return nil
}
/*
//////
////// 9:01 twice
//////
var d = new Date("3/10/2019, 01:59:00");
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
// tzUTC:Sun, 10 Mar 2019 08:59:00 GMT
var d = new Date("3/10/2019, 02:01:00");
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
// tzUTC:Sun, 10 Mar 2019 09:01:00 GMT
var d = new Date("3/10/2019, 02:59:00");
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
// tzUTC:Sun, 10 Mar 2019 09:59:00 GMT
var d = new Date("3/10/2019, 03:01:00");
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
// tzUTC:Sun, 10 Mar 2019 09:01:00 GMT
//////
////// 8:01 never
//////
var d = new Date("11/03/2019, 01:59:00");
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
// tzUTC:Sun, 03 Nov 2019 07:59:00 GMT
var d = new Date("11/03/2019, 02:01:00");
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
// tzUTC:Sun, 03 Nov 2019 09:01:00 GMT
var d = new Date("11/03/2019, 02:59:00");
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
// tzUTC:Sun, 03 Nov 2019 09:59:00 GMT
var d = new Date("11/03/2019, 03:01:00");
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
tzUTC:Sun, 03 Nov 2019 10:01:00 GMT
*/