Go's time doesn't work under the docker image from scratch

Question

Go code:

package main

import (
    "fmt"
    "time"
)

func main() {
    var local,_ = time.LoadLocation("Asia/Shanghai")
    fmt.Println(time.Now())
    fmt.Println(time.Now().In(local))
}

Dockerfile:

FROM scratch
COPY ./main /main
CMD [ "/main" ]

build.sh:

rm -rf main
CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o main  . 
docker build -t hello-go .
docker run hello-go

All the file are in one folder named hello-go. When I run my Go code in my osx. It works.

➜  hello-go go run main.go
2017-12-13 21:50:53.482933 +0800 CST m=+0.000350077
2017-12-13 21:50:53.483007 +0800 CST

When i build the docker image and start it. one error like this:

➜  hello-go ./build.sh
Sending build context to Docker daemon  1.937MB
Step 1/3 : FROM scratch
 --->
Step 2/3 : COPY ./main /main
 ---> 80da783f6c5d
Step 3/3 : CMD /main
 ---> Running in 85cb022b3ce2
 ---> 485ddd3a08dd
Removing intermediate container 85cb022b3ce2
Successfully built 485ddd3a08dd
Successfully tagged hello-go:latest
2017-12-13 13:52:59.861173734 +0000 UTC m=+0.000252335
panic: time: missing Location in call to Time.In

goroutine 1 [running]:
time.Time.In(0xbe846a0ef355744e, 0x4d607, 0x539b80, 0x0, 0x0, 0x0, 0xc420037f70)
        /usr/local/go/src/time/time.go:1073 +0xc0
main.main()
        /Users/liujichun/Desktop/workspace/docker/hello-go/main.go:11 +0xee
➜  hello-go

I know the scratch image is empty. What should i do to make it.

This post should point you in the right direction - https://www.goinggo.net/2013/08/using-time-timezones-and-location-in-go.html — johnharris85, Dec 13 '17 at 14:17
Were do you expect the timezone information come from if you build your image from scratch? — Volker, Dec 13 '17 at 14:21
From the image environment variable or write in the golang code. — JICHUN, Dec 13 '17 at 14:27
I just want a minimum image to run go binary file. Empty is best. — JICHUN, Dec 13 '17 at 14:31
You need to add the TZ data file. If the app uses TLS, you will also need to include root certs. — Charlie Tumahai, Dec 13 '17 at 14:40
OK, it's a good idea. Now I should find a way to reduce the TZ data file size. — JICHUN, Dec 13 '17 at 15:11
You can include a subset of the zone info. Perhaps include Asia/Shanghai and UTC only. — Charlie Tumahai, Dec 13 '17 at 16:36

score 5 · Answer 1 · edited Mar 19 '21 at 16:04

I think the proper way to solve this is to import tzdata as the library wants it to be. You can make use of the TZ environment variable.

The solution is indicated in a Dockerfile which I found on GitHub here

To wrap up everything:

FROM golang:alpine AS build
RUN apk update && apk add ca-certificates && apk add tzdata
WORKDIR /app
ADD . .
RUN CGO_ENABLED=0 GOOS=linux go build -o myapp

FROM scratch AS final
COPY --from=build /usr/share/zoneinfo /usr/share/zoneinfo
COPY --from=build /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
COPY --from=build /app/myapp /

ENV TZ Australia/Sydney
ENTRYPOINT ["/myapp"]

score 5 · Answer 2 · answered May 27 '21 at 01:01

5

Starting from Go 1.15, time/tzdata is available, just import the package in your main package.

Reference: https://golang.org/pkg/time/tzdata/

answered May 27 '21 at 01:01

John Takeuchi Hiroki

91
1
4

This solved it for me. – TheQuestioner Dec 23 '21 at 01:42

score 3 · Answer 3 · answered Jun 02 '20 at 19:38

3

Docker FROM alphine

RUN apk --no-cache add tzdata

see answer in: https://stackoverflow.com/a/62159987/4143613

answered Jun 02 '20 at 19:38

erajuan

2,224
20
31

Using alpine opens your container up to more attack vectors and is a heavy-handed approach. Using scratch is not only fine, but a good idea if you're going for security or performance. If you want access to platform-independent timezones, the above answer to use tz is honestly better. – Jyosua Oct 19 '20 at 02:27

score 2 · Accepted Answer · answered Mar 03 '20 at 09:37

2

Using this library https://godoc.org/4d63.com/tz

Their example (see tz.LoadLocation):

t := time.Date(2009, time.November, 10, 23, 0, 0, 0, time.UTC)
fmt.Println(t)

syd, _ := tz.LoadLocation("Australia/Sydney")
fmt.Println(t.In(syd))

// Output:

// 2009-11-10 23:00:00 +0000 UTC
// 2009-11-11 10:00:00 +1100 AEDT

answered Mar 03 '20 at 09:37

luismartingil

1,029
11
16

This is no longer necessary (as of Go 1.15). You only need to import "time/tzdata" (prefix it with underscore) to get an embedded time zone database. – Mani Dec 20 '22 at 23:13

Go's time doesn't work under the docker image from scratch

4 Answers4