Evaluate templating system alternatives

[muuki88]

Status Quo

Native-packager has currently a homemade templating system, which has scaled well so far. It provides the following features

• one-time resolving of placeholders
• bash and bat friendly surroundings ( ${{placeholder}} and @@placeholder@@ )
• different charsets and eol styles
• placeholder definition as Seq[(String,String)], allowing duplicate additions

These features limited the usage in many ways, which lead to the following hard to use/debug issues

• Template nesting is done with placeholders, which means the value's in the replacements: Seq[(String,String)] become incredible large strings, making debugging hard and nested resolving a manual work.
• Different placeholder styles need additional configuration
• No typing for template and global namespaces (linuxScriptReplacements, bashScriptReplacements) lead to a lot of clutter and hard to understand mechanisms
• Untested internal library

Requirements

The experience lead to the following requirements

• Typed templates as much as possible
• Separate namespaces for templates
• Testable: unit tests and shellcheck tests
• Nesting of templates
• Recursive resolving
• Support optional values
• Scala 2.10 or Java

Acceptance Criteria

• [ ] All templates use the new templating system
• [ ] All bash scripts are tested with shellcheck

[muuki88]

First candidate is scalate with mustache templates.

[muuki88]

sbt-pack uses twirl.