heredoc handling

[sbalbach]

is there a reason that the contents of heredoc blocks are loaded as a single string instead of as json? If a single line is added at the bottom of the _end_heredoc() method like this:

t.value = json.loads(t.value)

the contents of the heredoc will be accessible as a dictionary like the rest of the document.

[scottbelden]

Could you give an example of an HCL file that shows what you mean?

[sbalbach]

Sorry, can't seem to get it to show as code..

resource "aws_iam_user_policy" "lb_ro" {
  name = "test"
  user = "someUser"

  policy = <<EOF
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Action": [
        "ec2:Describe*"
      ],
      "Effect": "Allow",
      "Resource": "*"
    }
  ]
}
EOF
}

Currently it returns as:

'aws_iam_user_policy': {'lb_ro': {'name': 'test', 'user': 'someUser', 'policy': '{\n  "Version": "2012-10-17",\n  "Statement": [\n    {\n      "Action": [\n        "ec2:Describe*"\n      ],\n      "Effect": "Allow",\n      "Resource": "*"\n    }\n  ]\n}'}}

I would like it to return as:

'aws_iam_user_policy': {'lb_ro': {'name': 'test', 'user': 'someUser', 'policy': {'Version': '2012-10-17', 'Statement': [{'Action': ['ec2:Describe*'], 'Effect': 'Allow', 'Resource': '*'}]}}}

[scottbelden]

I see. Unfortunately I don't believe there is any requirement that heredocs must be in some JSON structure. For example, the official HCL repo has a test where the heredoc is not in a JSON structure: https://github.com/hashicorp/hcl/blob/master/test-fixtures/multiline.hcl

Therefore, this is something that would have to be done in post processing.

[sbalbach]

ok, small change; this allows it to work both ways

        try:
            t.value = json.loads(t.value)
        except:
            pass

HCL:

resource "aws_iam_user_policy" "badJson" {
name = "test"
user = "someUser"

policy = <<EOF
bar
baz
EOF
}

resource "aws_iam_user_policy" "goodJson" {
name = "test"
user = "someUser"

policy = <<EOF
{
"Version": "2012-10-17",
"Statement": [
{
"Action": [
"ec2:Describe*"
],
"Effect": "Allow",
"Resource": "*"
}
]
}
EOF
}

output showing both:
'aws_iam_user_policy': {'badJson': {'name': 'test', 'user': 'someUser', 'policy': 'bar\nbaz'}, 'goodJson': {'name': 'test', 'user': 'someUser', 'policy': {'Version': '2012-10-17', 'Statement': [{'Action': ['ec2:Describe*'], 'Effect': 'Allow', 'Resource': '*'}]}}}

[scottbelden]

Yes, that could be done, but it would be a breaking change for anyone that has a heredoc that is JSON-like but they expect it to be loaded as a string. Everything I have found regarding heredocs seems to indicate that the contents should be treated as a string and not implicitly converted to something else.

[virtuald]

Agree. If you want the contents of the heredoc to not be a string, don't use a heredoc, use HCL structure instead.

Of course, this seems to be driven by a terraform use case. If someone were to create a library that specifically handled terraform files, then it might be appropriate in that library to do the transform you're asking for. However, pyhcl is just a HCL parser, and should not contain any terraform-specific hacks.