Golang text template - time.Format epoch

[skru...@cloud.upwork.com]

Hello

I have a field in my text template: "start":"{{.Start.Format "Jan 02, 2006 15:04:05 UTC"}}"

But, I want to have output as epoch time. E.g. 148110633400 

Could you please explain how to do this ? Thanks

[Marvin Renich]

* skrutsko via golang-nuts <golan...@googlegroups.com> [161207 08:30]:

Do you mean Unix time (seconds since Jan 1, 1970 UTC)? Try

"{{.Start.Unix}}"

Note that in your Format above, UTC should probably be MST to print the
time zone associated with Start. Also, I presume your code has the
double quotes properly escaped for their context, which does not appear
to be done above (though the context is not clear; a more complete
example would be more helpful).

...Marvin

[Sergey Krutsko]

Thanks Marvin!

that's exactly what i need

bwt, is there any way to get current timestamp inside the template (without referencing to the data structure) ?

something like that:

"timestamp: {{time.Now.Unix}}"

[Marvin Renich]

* 'Sergey Krutsko' via golang-nuts <golan...@googlegroups.com> [161208 02:12]:

> Thanks Marvin!
>
> that's exactly what i need
>
> bwt, is there any way to get current timestamp inside the template (without
> referencing to the data structure) ?
>
> something like that:
> "timestamp: {{time.Now.Unix}}"

You can use a template.FuncMap.

If, by "without referencing to the data structure", you mean without
adding anything additional to the data structure, then you will have to
use a FuncMap. If you mean "without adding the current time as a value
to the data structure", but will allow adding functions to the data
structure, then there is another way. Add a field (or map element) to
the data of some func type (e.g. func() time.Time) and use call inside
the template.

The playground link https://play.golang.org/p/9rsVDBPzy2 demonstrates
both methods.

When using a FuncMap, it must be defined on the template (with a call to
Funcs) before parsing any template that uses it. If you are using
ParseFiles or ParseGlob, rather than Parse, this is a little tricky, and
the template documentation could be improved significantly to address
the issue.

The helper functions ParseFiles and ParseGlob (at the package level,
rather than the methods on *Template) cannot be used because there is no
way to pass a FuncMap before parsing.

If you try something like

var t, err = template.New("").Funcs(fm).ParseFiles(file)
// handle error, then...
err = t.Execute(os.Stdout, data)

you will get an error containing

... "" is an incomplete or empty template;...

The problem is that t is an empty template with name "", and the
template(s) resulting from ParseFiles is only an associated template
with a name derived from the file name. So t.Execute() attempts to
execute the empty template. There are at least two ways to make it
work. One way is to replace the first line above with

var t, err = template.New(filepath.Base(file)).Funcs(fm).ParseFles(file)

and the other is to replace the Execute line above with

err = t.ExecuteTemplate(os.Stdout, t.Templates()[0].Name(), data)

A third way would be to use ioutil.ReadFile to read the whole file and
then call t.Parse on the string obtained from that. Using this method,
the result of Parse is used as the template t, not as an associated
template with a different name.

...Marvin

[Sergey Krutsko]

Thanks Marvin for a very comprehensive answer!

I will check it out.