Multiple rendering - Render template once per CSV record

[safferyj]

My use case is to make multiple API calls using a JSON template document with substituted values from each line of a CSV data file. I am on Windows and not a Go programmer but hoping that gomplate will be a suitable tool for this.

For example, if I have a file test.json as:

{
    "a": "1",
    "b": "2",
    "c": "hello"
}

And can make an API call with:

type test.json | curl --request POST --header "Content-Type: application/json" --data-binary @- http://api/

Then, can I make a single call to gomplate with a data file like this

a,b,c
1,2,hello
3,4,world
5,6,yippee
7,8,yay

and a template file something like this

{
    "a": "{{.a}}",
    "b": "{{.b}}",
    "c": "{{.c}}"
}

and achieve 4 calls to the API?

I have spent some time trying various options but have not had any success. Many thanks.

[hairyhenderson]

Hi @safferyj, in general gomplate doesn't support POSTing to HTTP datasources. It uses GET for those.

But, if the API was constructed differently and could accept the payload as URL query parameters you could accomplish it by feeding a subpath argument to the datasource/ds function - see https://docs.gomplate.ca/functions/data/#datasource

[safferyj]

Thanks. I was thinking of using the --exec-pipe feature to pipe the rendered template to curl. If doing this, is it possible somehow to render the template multiple times with the data for each occurrence coming from a line read from CSV?

[hairyhenderson]

The process called by --exec-pipe is only called once. To accomplish what you're looking for I think you'd need to just wrap the command in a shell script and loop it.

[safferyj]

Thanks. I arrived at the gomplate and curl plugin solution posted below.

[safferyj]

On Windows, with

type template.tmpl
{
    "a": "{{.a}}",
    "b": "{{.b}}",
    "c": "{{.c}}"
}

and

type data.csv
a,b,c
1,2,hello
3,4,world
5,6,yippee
7,8,yay

then

gomplate --plugin curl=curl.exe -t template.tmpl -d data.csv -i "{{$data := include `data` | csvByRow}}{{range $data}}{{$render := tmpl.Exec `template.tmpl` .}}{{curl `--silent` `--json` $render `http://api`}}{{end}}"

will make the following four distinct POST API calls

{
    "a": "1",
    "b": "2",
    "c": "hello"
}

{
    "a": "3",
    "b": "4",
    "c": "world"
}

{
    "a": "5",
    "b": "6",
    "c": "yippee"
}

{
    "a": "7",
    "b": "8",
    "c": "yay"
}