Postee templates

[afdesk]

Problem

Currently every integration implements set of methods to apply formatting to message. List of formatting options:

type LayoutProvider interface {
	TitleH1(title string) string
	TitleH2(title string) string
	TitleH3(title string) string
	ColourText(text, color string) string
	Table(rows [][]string) string
	P(p string) string
	A(url, title string) string
}

Postee 1.x has only one type of input - scan result and there was a procedure that build payload using predefined json structure and calls to methods above.

Postee 2.x has support for audit events and and input json is no more predefined and existing procedure won’t work correctly. So there is a problem how to add formatting to messages which are sent to integrations.

Possible solutions

REGO rules

REGO rules allow to filter a payload. But we need a way to convert data from JSON to some format which Postee will be able render to Plugin formats (html, markdown, Atlassian DF etc.).

Special JSON structure

JSON nodes include enough information to call layout methods like:

{
  type : "p",
  text : "Image scanned",
  children: [...]
}

Simple JSON rendering

Kind of simple implementation when JSON property key is rendered as bold text and value as simple text and both key and value are on same line like:
Image: alpine

JSON array could be rendered as tables where properties are columns and every item is row

Go Templates

Using Go Templates will allow to filter payloads and discard unnecessary data. But Go template will render a string, what will we do with table?

Any templating engine producing XML

json is pre processed and applied to template and result is something like

<TitleH1>Image Scanned</TitleH1>
<A url="http://google.com">Google</a>
<Table>
  <Tr>
      <Td>1</Td>
  </Tr>
</Table>

So layout methods can be called based on tag name and attributes.

Written by @AndreyLevchenko