How to use user variables with file provisioner in Packer?

Question

I have a packer json like:

"builders": [{...}],
"provisioners": [
          {
                "type": "file",
                "source": "packer/myfile.json",
                "destination": "/tmp/myfile.json"
           }
  ],
"variables": {
        "myvariablename": "value"
 }

and myfile.json is:

{
   "var" : "{{ user `myvariablename`}}"
}

The variable into the file does get replaced, is a sed replacement with shell provisioner after the file the only option available here?

Using packer version 0.12.0

You can have ansible drive packer, makes things more flexible as it is awesome at templating. — John Humphreys, Feb 13 '19 at 14:49
ansible is a procedural workflow which is not good for provisioning pipelines in the long term — Michael Martinez, Aug 02 '22 at 15:35

score 12 · Answer 1 · edited Mar 30 '18 at 18:54

12

You have to pass these as environment variables. For example:

  "provisioners": [
    {
      "type": "shell"
      "environment_vars": [
        "http_proxy={{user `proxy`}}",
      ],
      "scripts": [
        "some_script.sh"
      ],
    }
  ],
  "variables": {
    "proxy": null
  }

And in the script you can use $http_proxy

edited Mar 30 '18 at 18:54

slm

15,396
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answered Jun 21 '17 at 13:54

Rickard von Essen

4,110
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1

environment_vars works just for the shell provisioner, not for the file: https://www.packer.io/docs/provisioners/file.html – MarMan Jun 21 '17 at 14:07

score 1 · Answer 2 · answered Mar 06 '19 at 10:02

1

So far I've come just with the solution to use file & shell provisioner. Upload file and then replace variables in file via shell provisioner which can be fed from template variables provided by e.g. HashiCorp Vault

answered Mar 06 '19 at 10:02

aRagornol

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score 0 · Answer 3 · answered Oct 15 '20 at 14:20

Yo may use OS export function to set environment and pass it to Packer

Here is a config using OS ENV_NAME value to choose local folder to copy from export ENV_NAME=dev will set local folder to dev

{
  "variables": {
    ...
    "env_folder": "{{env `ENV_NAME`}}",
  },
  "builders": [{...}]
  "provisioners": [
    {
      "type": "file",
      "source": "files/{{user `env_folder`}}/",
      "destination": "/tmp/"
    },
    {...}
  ]
}

score -3 · Answer 4 · answered Jun 21 '17 at 10:27

User variables must first be defined in a variables section within your template. Even if you want a user variable to default to an empty string, it must be defined. This explicitness helps reduce the time it takes for newcomers to understand what can be modified using variables in your template.

The variables section is a key/value mapping of the user variable name to a default value. A default value can be the empty string. An example is shown below:

 {
 "variables": {
"aws_access_key": "",
 "aws_secret_key": ""
 },

"builders": [{
"type": "amazon-ebs",
"access_key": "{{user `aws_access_key`}}",
"secret_key": "{{user `aws_secret_key`}}",
// ...
}]
}

check this link for more information

Thanks Favour, but the question is more about how to use the variables in an external file (with file provisioner) used by Packer — MarMan, Jun 21 '17 at 10:31

How to use user variables with file provisioner in Packer?

4 Answers4

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