packer-cn/website/source/docs/commands/console.html.md

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The `packer console` command allows you to experiment with Packer variable interpolations.	docs	packer console - Commands	docs-commands-console

console Command

The packer console command allows you to experiment with Packer variable interpolations. You may access variables in the Packer config you called the console with, or provide variables when you call console using the -var or -var-file command line options.

Type in the interpolation to test and hit to see the result.

To exit the console, type "exit" and hit , or use Control-C.

$ packer console my_template.json

The full list of options that the console command will accept is visible in the help output, which can be seen via packer console -h.

Options

• -var - Set a variable in your packer template. This option can be used multiple times. This is useful for setting version numbers for your build. example: -var "myvar=asdf"

• -var-file - Set template variables from a file. example: -var-file myvars.json

REPL commands

• help - displays help text for Packer console.

• exit - exits the console

• variables - prints a list of all variables read into the console from the -var option, -var-files option, and template.

Usage Examples

Let's say you launch a console using a Packer template example_template.json:

$ packer console example_template.json

You'll be dropped into a prompt that allows you to enter template functions and see how they're evaluated; for example, if the variable myvar is defined in your example_template's variable section:

"variables":{
	"myvar": "asdfasdf"
},
...

and you enter {{user myvar}} in the Packer console, you'll see the value of myvar:

> {{user `myvar`}}
> asdfasdf

From there you can test more complicated interpolations:

> {{user `myvar`}}-{{timestamp}}
> asdfasdf-1559854396

And when you're done using the console, just type "exit" or CTRL-C

> exit
$

If you'd like to provide a variable or variable files, you'd do this:

packer console -var "myvar=fdsafdsa" -var-file myvars.json example_template.json

If you don't have specific variables or var files you want to test, and just want to experiment with a particular template engine, you can do so by simply calling packer console without a template file.

If you'd like to just see a specific single interpolation without launching the REPL, you can do so by echoing and piping the string into the console command:

$ echo {{timestamp}} | packer console
1559855090