More mixing with YTT

Mixin.yaml

version: "1.0"

---
#@ load( "@ytt:overlay", "overlay" )
#@ load( "@ytt:template", "template" )

---

#@ def _mixin_array( path, value ):
#@   if path[ 0 ].endswith( "prefix" ):

#@overlay/match by=overlay.index( 0 )
#@overlay/insert before=True
- #@ value if len( path ) == 1 else _mixin( path[1:], value )

#@   elif path[ 0 ].endswith( "append" ) or path[ 0 ] == "-":

#@overlay/append
- #@ value if len( path ) == 1 else _mixin( path[1:], value )

#@   end
#@ end

---

#@ def _mixin_map( path, value ):
#@   if len( path ) == 0:

_: #@ template.replace( value )

#@   elif len( path ) == 1:

#@yaml/text-templated-strings
(@= path[ 0 ] @): #@ value

#@   else:

#@yaml/text-templated-strings
(@= path[ 0 ] @): #@ _mixin( path[1:], value )

#@   end
#@ end

---

#@ def _mixin( path, value ):
#@   if len( path ) and path[ 0 ].startswith( "-" ):
#@     return _mixin_array( path, value )
#@   else:
#@     return _mixin_map( path, value )
#@   end
#@ end

---

#@ def mixin( path, *values ):
#@   for value in values:
---
#@overlay/match by=overlay.all
#@overlay/match-child-defaults missing_ok=True
--- #@ _mixin( path, value )
#@   end
#@ end

---

---
#@ def fragment( ):
services:
  fifth:
    property: "with value"
#@ end
---

#@ def more_services( ):
sixth: { }
seventh: { }
#@ end

#@overlay/match by=overlay.all
#@overlay/match-child-defaults missing_ok=True
---
services:
  first: {}    
  second: 
    replace_me: "bla bla"
  third: { }
  
--- #@ template.replace( mixin( [ "services", "first", "thing" ], "abc" ) )
--- #@ template.replace( mixin( [ "services", "second", "replace_me" ], 123 ) )
--- #@ template.replace( mixin( [ "services", "third", "list", "-" ], 1, 2, 3 ) )
--- #@ template.replace( mixin( [ "services", "third", "list", "-append" ], 4, 5, 6 ) )
--- #@ template.replace( mixin( [ "services", "third", "list", "-prefix" ], 7, 8, 9 ) )
--- #@ template.replace( mixin( [ "services", "forth", "list", "-" ], "a", "b", "c" ) )
--- #@ template.replace( mixin( [ ], fragment( ) ) )
--- #@ template.replace( mixin( [ "services", "fifth", "other" ], "property" ) )
--- #@ template.replace( mixin( [ "services" ], more_services( ) ) )