fix build name ConfigTemplate processing [GH-858]

[jasonberanek]

Addresses issue with build name ConfigTemplate processing causes errors with -only and -except command line flags, and with post-processor and provisioner only and except attributes.

The approach allows backwards compatibility with anyone using a build name template string (e.g., {{user "foo"}}) in -only or -except command line calls.

Also, added tests to verify behavior in the command line, provisioner definition, and post-processor definition.

I'd appreciate a head-nod that this looks good from another committer.

/cc @strcrzy

[strcrzy]

i will gladly take a look at this asap

[nchammas]

What's the status of this PR? Still waiting for review?

I'd help review it, but I'm brand new to Packer and Go.

[nchammas]

Alright, check out this Packer template:

{
  "variables": {
    "aws_access_key": "{{env `AWS_ACCESS_KEY_ID`}}",
    "aws_secret_key": "{{env `AWS_SECRET_ACCESS_KEY`}}",
    "spark_version": "1.1.0"
  },

  "builders": [
    {
      "name": "spark:base:us-east-1:ebs:hvm",
      "type": "amazon-ebs",
      "access_key": "{{user `aws_access_key`}}",
      "secret_key": "{{user `aws_secret_key`}}",
      "region": "us-east-1",
      "source_ami": "ami-08842d60",
      "instance_type": "m3.medium",
      "ssh_username": "ec2-user",
      "ami_name": "Spark Base HVM {{timestamp}}",
      "ami_description": "Spark Base HVM AMI",
      "ami_groups": ["all"],
      "ami_virtualization_type": "hvm"
    },
    {
      "name": "spark:{{user `spark_version`}}:us-east-1:ebs:hvm",
      "type": "amazon-ebs",
      "access_key": "{{user `aws_access_key`}}",
      "secret_key": "{{user `aws_secret_key`}}",
      "region": "us-east-1",
      "source_ami": "ami-08842d60",
      "instance_type": "m3.medium",
      "ssh_username": "ec2-user",
      "ami_name": "Spark {{user `spark_version`}} HVM {{timestamp}}",
      "ami_description": "Spark {{user `spark_version`}} HVM AMI",
      "ami_groups": ["all"],
      "ami_virtualization_type": "hvm"
    }
  ],

  "provisioners": [
    {
      "type": "shell",
      "execute_command": "chmod +x {{ .Path }}; {{ .Vars }} sudo -E sh -x '{{ .Path }}'",
      "inline": [
        "echo 'This will obviously work.'"
      ],
      "pause_before": "5s"
    },
    {
      "type": "shell",
      "only": [
        "spark:{{user `spark_version`}}:us-east-1:ebs:hvm"
      ],
      "execute_command": "chmod +x {{ .Path }}; {{ .Vars }} sudo -E sh -x '{{ .Path }}'",
      "inline": [
        "echo 'How about this? ༼⁰o⁰；༽'"
      ]
    }
  ]
}

Note that one builder has a static name, while the other has a name that depends on a user-defined variable.

I tried master at 7e4dfcd283 on this template and I didn't get any ༼⁰o⁰；༽. I then applied this patch and retried, and sure enough, I got ༼⁰o⁰；༽ all up in my face.

From my little test, this patch gets a 👍 from me.

[nchammas]

@jasonberanek Do you know if this PR will be reviewed and merged in in time for the 0.7.3 release (or whatever the next release is)? The issue it addresses, #858, is a bug in the basic usability of template variables.

[jasonberanek]

@nchammas Thanks for testing the patch, and verify it works as expected.

I apologize for not responding sooner, been pulled away from working Packer things. I'll do my best to get this in the pipe for the next release. I still want at least another committer to ok before I push, so I'll reach out to them to get another set of eyes on it.

[nchammas]

Okie doke. Thanks for the update!

[thewwr]

Could you please merge this PR? It would be important and appreciated. Thank you!

[sethvargo]

@jasonberanek this looks good to me. Great work!