Improvement: allow triple quoted strings within JSON body

[sparrowt]

Firstly thank you for this excellent provider! I'm filing this to track a desirable feature, but appreciate that (like me!) you may well have no desire or time to implement it. Nevertheless perhaps someone else or one of us will in future.

Summary: it would be really handy if the body of certain resources (e.g. watchers) was allowed to contain triple-quoted strings in the format sometimes returned by Elastic via Kibana dev tools (e.g. to allow multi-line strings within JSON, delimited by """).

For example, to include a non-trivial amount of detail in the email action > body > html then you have to write it all on one line e.g. like this, which gets unwieldy to edit and for source control etc:

resource "elasticsearch_xpack_watch" "my-watcher" {
  watch_id = "my-watcher-id"
  body = <<EOF
{
  ...
  "actions": {
    "email_people": {
      "email": {
        ...
        "body": {
          "html": "<p>Some details:</p><ul>{{#ctx.payload.aggregations.foo.buckets}}<li>{{bar}}</li>{{/ctx.payload.aggregations.foo.buckets}}</ul> \n\n <p>Other details:</p><ul>...</ul> \n\n etc..."
        }
      }
    }
  }
}
EOF
}

It would be amazing if we could instead do this:

resource "elasticsearch_xpack_watch" "my-watcher" {
  watch_id = "my-watcher-id"
  body = <<EOF
{
  ...
  "actions": {
    "email_people": {
      "email": {
        ...
        "body": {
          "html": """
<p>Some details:</p>
<ul>
{{#ctx.payload.aggregations.foo.buckets}}
  <li>{{bar}}</li>
{{/ctx.payload.aggregations.foo.buckets}}
</ul>

<p>Other details:</p>
<ul>...</ul>

etc...
"""
        }
      }
    }
  }
}
EOF
}

Currently this fails due to ValidateFunc being set to validation.StringIsJSON e.g. in the case of elasticsearch_xpack_watch that is here: https://github.com/phillbaker/terraform-provider-elasticsearch/blob/v2.0.4/es/resource_elasticsearch_xpack_watch.go#L27

[sparrowt]

A very similar case is the embedded JSON needed in the body of the webhook action.

Workaround

For now (and this should work for the email html body too I imagine) my workaround is to use templatefile (to load multi-line JSON as a string) followed by Terraform's format with %q` to escape it for inclusion within a string, e.g. like this:

resource "elasticsearch_xpack_watch" "my-watcher" {
  watch_id = "my-watcher-id"
  body = templatefile(
    "${path.module}/my-watcher-template.tftpl",
    {
      secret_teams_webhook_path = ...
      teams_webhook_body_json_escaped = format("%q", templatefile(
        "${path.module}/my-webhook-body-teams.tftpl",
        {
          teams_title = "Thing X went wrong"
        }
      ))
    }
  )
}

with my-watcher-template.tftpl defining the majority of the watcher JSON definition e.g:

{
  ...
  "actions": {
    "webhook_1": {
      "webhook": {
        "host": "...",
        "port": 443,
        "path": "${secret_teams_webhook_path}",
        "method": "post",
        "scheme": "https",
        "body": ${teams_webhook_body_json_escaped}
      }
    }
  }
}

but with the webhook body interpolated from the escaped contents of my-webhook-body-teams.tftpl where you can define your webhook JSON body unescaped and over multiple lines e.g:

{
  "@type": "MessageCard",
  "@context": "https://schema.org/extensions",
  "summary": "${teams_title}",
  "themeColor": "0078D7",
  "sections": [
    {
      "activityTitle": "${teams_title}"
    }
  ],
  ...
}

Note that the string produced by format includes the opening & closing " quotes so in the watcher template you do "body": ${teams_webhook_body_json_escaped} rather than "body": "${teams_webhook_body_json_escaped}".

[phillbaker]

@sparrowt thanks for opening the issue - I have wished for the triple quoted strings as well. Your approach is a valid workaround.

I think my general suggestion for a workaround would be to use HCL to build the objects and convert that to JSON, e.g.:

body = jsonencode({
  test = {
    "is_write_index" = true
  }
  foo = <<-EOT
  hello new 
    line world
  EOT
})

One potential way to implement this directly is to use a extension of JSON like JSON5. However, the public go implementations I saw were all archived, e.g. https://github.com/flynn/json5.

I think a helpful outcome of this issue would be to document these two workarounds as suggested approaches.