Allow the /{db}/_index endpoint to accept jq definitions

We currently have to create jq-based indexes by writing out the whole
design document containing the Mango index definition, because the
`/{db}/_index` endpoint does not except anything except "asc" or "desc"
next to field names in the sort syntax.

Here we expand this to allow { "$jq": "..." } as well, letting us create
jq-based indexes without knowing the internal document format.

Even though internally we support mixing jq expressions with normal
field lookups in multi-field indexes, for now I'm restricting this so
that multi-field indexes have to either all use the same sort direction,
or all be jq expressions.

src/mango/src/mango_sort.erl

@@ -49,20 +49,24 @@ sort_field({[{Name, <<"asc">>}]}) when is_binary(Name) ->
  {Name, <<"asc">>};
 sort_field({[{Name, <<"desc">>}]}) when is_binary(Name) ->
  {Name, <<"desc">>};
+sort_field({[{Name, {[{<<"$jq">>, Expr}]} = Jq}]}) when is_binary(Name) and is_binary(Expr) ->
+ {Name, Jq};
 sort_field({Name, BadDir}) when is_binary(Name) ->
  ?MANGO_ERROR({invalid_sort_dir, BadDir});
 sort_field(Else) ->
  ?MANGO_ERROR({invalid_sort_field, Else}).
 
 validate({Props}) ->
- % Assert each field is in the same direction
- % until we support mixed direction sorts.
- Dirs = [D || {_, D} <- Props],
+ % Assert each field is in the same direction, or all fields are jq
+ % expressions, until we support mixed direction sorts.
+ Dirs = lists:map(fun(Prop) ->
+ case Prop of
+ {_, {[{<<"$jq">>, _}]}} -> jq;
+ {_, D} -> D
+ end
+ end, Props),
  case lists:usort(Dirs) of
- [] ->
- ok;
- [_] ->
- ok;
- _ ->
- ?MANGO_ERROR({unsupported, mixed_sort})
+ [] -> ok;
+ [_] -> ok;
+ _ -> ?MANGO_ERROR({unsupported, mixed_sort})
  end.

src/mango/test/22-index-function-test.py

@@ -13,44 +13,22 @@
 import mango
 
 
-def create_index(db, ddoc_id, view_id, definition):
- db.save_docs(
- [
- {
- "_id": ddoc_id,
- "language": "query",
- "views": {
- view_id: {
- "map": {"fields": definition, "partial_filter_selector": {}},
- "reduce": "_count",
- "options": {"def": {"fields": definition}},
- }
- },
- }
- ]
- )
-
-
 class IndexFunctionTests(mango.DbPerClass):
  @classmethod
  def setUpClass(klass):
  super(IndexFunctionTests, klass).setUpClass()
 
- create_index(
- klass.db,
- "_design/jq-split-1",
- "jq-json-index",
- {"f1_words": {"$jq": '.f1 | split(" ") | .[]'}},
+ klass.db.create_index(
+ [
+ {"f1_words": {"$jq": '.f1 | split(" ") | .[]'}},
+ ]
  )
 
- create_index(
- klass.db,
- "_design/jq-split-2",
- "jq-json-index",
- {
- "f2_words": {"$jq": '.f2 | split(" ") | .[]'},
- "f3_words": {"$jq": '.f3 | split(" ") | .[]'},
- },
+ klass.db.create_index(
+ [
+ {"f2_words": {"$jq": '.f2 | split(" ") | .[]'}},
+ {"f3_words": {"$jq": '.f3 | split(" ") | .[]'}},
+ ],
  )
 
  klass.db.save_docs(