Template Should Not Evaluate Outside The Templating Expression Marks (eg `{{ }}`)

Template Evaluation Outside Templating Expression Marks in Configu

Configu is a powerful templating engine that allows users to create dynamic templates with ease. However, in some cases, the evaluation of values outside the templating expression marks ({{ }}) can lead to unexpected behavior. In this article, we will discuss the current behavior of Configu, the expected behavior, and provide a solution to this issue.

With my previous experience working with templating stuff, the evaluation of values should only happen between {{ }}, and outside the {{ }} should remain untouched/unchanged. However, it is not the case in Configu. For example, if we have a file back-tick.txt with the following content:

`

Running configu eval | configu export --template examples/back-tick.txt will give the following output:

configu eval | configu export --template examples/back-tick.txt 
│
◇  Configs evaluated successfully
│
■  template expression evaluation failed: Error: Failed to evaluate expression "````"
│  "" is not a function

As expected, the output should be the same as the input, which is just the back-tick character. However, Configu evaluates the value outside the templating expression marks, resulting in an error.

Another example is the line break character \n. If we have a line-break.json file with the following content:

{
  "title": "Hello",
  "paragraph": "{{$.configs.MESSAGE.value}}\nIt is a nice day"
}

Running configu eval | configu export --template examples/line-break.json will give the following output:

{
  "title": "Hello",
  "paragraph": "Hi there!
It is a nice day"
}

As expected, the output should be the same as the input, which is a JSON object with a paragraph that contains a line break character. However, Configu evaluates the value outside the templating expression marks, resulting in a broken JSON syntax.

The expected behavior of Configu is to not evaluate the values outside the templating expression marks. In other words, the values outside the {{ }} should remain untouched/unchanged. This means that the output of the previous examples should be the same as the input.

Unfortunately, there is no clear way to reproduce this issue, as it seems to be a bug in Configu. However, the examples provided above demonstrate the issue.

There is no additional context to provide, as this issue seems to be a bug in Configu.

To avoid this issue, we need to prepend a backslash (\) before the values that we want to remain untouched/unchanged. For example, in the back-tick.txt file, we can change the content to:

\`

And in the line-break.json file, we can change the content to:

{
  "title": "Hello",
  "paragraph": "{{$.configs.MESSAGE.value}}\\nIt is a nice day"
}

By prepending a backslash before the values, we can avoid the evaluation of values outside the templating expression marks.

In conclusion, the current behavior of Configu is to evaluate values outside the templating expression marks, resulting in unexpected behavior. The expected behavior is to not evaluate the values outside the {{ }}. To avoid this issue, we need to prepend a backslash before the values that we want to remain untouched/unchanged. We hope that this issue will be fixed in future versions of Configu.
Template Evaluation Outside Templating Expression Marks in Configu: Q&A

In our previous article, we discussed the issue of template evaluation outside templating expression marks in Configu. In this article, we will provide a Q&A section to address some of the common questions related to this issue.

A: The issue is that Configu evaluates values outside the templating expression marks ({{ }}), resulting in unexpected behavior. This can lead to errors and broken syntax in templates.

A: This issue is a problem because it can lead to errors and broken syntax in templates. For example, if a template contains a line break character (\n) outside the templating expression marks, Configu will evaluate it as a function call, resulting in a broken syntax.

A: To avoid this issue, you can prepend a backslash (\) before the values that you want to remain untouched/unchanged. For example, if you have a template with a line break character (\n) outside the templating expression marks, you can change it to \\n to avoid evaluation.

A: You need to prepend a backslash before the values because it tells Configu to treat the value as a literal string, rather than a function call. This prevents Configu from evaluating the value outside the templating expression marks.

A: No, this issue is not specific to Configu. Other templating engines may also have similar issues. However, Configu's behavior is particularly problematic because it can lead to errors and broken syntax in templates.

A: You can report this issue to the Configu team by submitting a bug report on their website or by contacting their support team directly. Be sure to provide a clear and concise description of the issue, along with any relevant code or examples.

A: We hope that this issue will be fixed in future versions of Configu. However, we cannot guarantee that it will be fixed, and it is up to the Configu team to decide whether to prioritize this issue.

In conclusion, the issue of template evaluation outside templating expression marks in Configu is a problem that can lead to errors and broken syntax in templates. To avoid this issue, you can prepend a backslash before the values that you want to remain untouched/unchanged. We hope that this issue will be fixed in future versions of Configu.