tink template create now accepts data from STDIN

[gauravgahlot]

At present, we create a template as shown below:

$ tink template create --name example --path /tmp/example.tmpl 

With the code changes in place, a user can now pipe the template data from a file. For example, if the data is saved in /tmp/example.tmpl, you can create a template with either of the following:

$ cat /tmp/example.tmpl | tink template create -n example
$ tink template create --name example --path /tmp/example.tmpl

Signed-off-by: Gaurav Gahlot [email protected]

[rgl]

You should just remove this commented line as its not used anymore.

[rgl]

--path /dev/stdin

You should remove this from the example that is on this PR description as there is no need to specify the path when it reads from stdin.

[gauravgahlot]

--path /dev/stdin

You should remove this from the example that is on this PR description as there is no need to specify the path when it reads from stdin.

I would prefer to keep it to make sure that people know about this.

[rgl]

--path /dev/stdin

You should remove this from the example that is on this PR description as there is no need to specify the path when it reads from stdin.

I would prefer to keep it to make sure that people know about this.

If you want to be able to use --path with stdin you should also implement the de-facto-standard way of configuring the application to read from stdin or write to stdout by using - as a path. For example, in wget (and tar etc) you do wget -O - example.com to write to stdout.

This because I'm not sure if all unices have a /dev/stdin and /dev/stdout devices, but if Tinkerbell is Linux only, we are good with that :-)

[grahamc]

While we're at it, I think we should reduce the globals used in this function and pass templateName as a parameter to the function to reduce spooky action. Could we do the same for filePath in readTemplateData?

[gauravgahlot]

AFIK, since templateName and filePath are value receivers for the flags, they have to be global. But if there is a better way to do that, please do let me know.

[grahamc]

What if we reversed this logic a bit, and instead got an io reader:

path, _: c.Flags().GetString(fPath)


if path != "" {
  reader, err = os.Open(filePath)
  ...
} else {
  reader = os.Stdin
}

and then just readAll(reader)? As it stands, it will fairly eagerly read the input from stdin even if I've passed a file.

[gianarb]

It looks good to me I don't have anything to add other what got already adressed