foreach + subtask breaks the templating engine

[rbeuque74]

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• I'm submitting a ...

  • bug report
  • feature request

• What is the current behavior?
  https://github.com/ovh/utask/blob/master/pkg/plugins/builtin/subtask/subtask.go#L43
  The subtask plugin uses an internal context object to exchange data between the main controller goroutine and itself.
  In foreach + subtask breaks the templating engine #54, we fixed a problem regarding the usage of hiphens inside the template (for the stepName). Now that we fixed it, a new bug has been introduced as the context is being json.Marshal, then, the double-quotes get escaped, which breaks the templating with error:
  failed to template context: Templating error: template: tmpl:1: unexpected "\\" in operand
  Faulty context example:
  {"task_id":"{{ if (index .step \"subTask-1\" \"output\") }}{{ index .step \"subTask-1\" \"output\" \"id\" }}{{ end }}","requester_username":"{{.task.requester_username}}"}

• Which version of uTask are you using?
  v1.2.0

• Internal reference
  CORDEV-138