Elasticsearch index aliases (w/ routing) and parent/child docs - elasticsearch

Question

I'm trying to set up an index with the following characteristics:
The index houses data for many projects. Most work is project-specific, so I set up aliases for each project, using project_id as the routing field. (And as an associated term filter.)
The data in question have a parent/child structure. For simplicity, let's call the doc types "mama" and "baby."
So we create the index and aliases:
curl -XDELETE http://localhost:9200/famtest
curl -XPOST http://localhost:9200/famtest -d '
{ "mappings" :
{ "mama" :
{ "properties" :
{ "project_id" : { "type" : "string", "index" : "not_analyzed" } }
},
"baby" :
{ "_parent" :
{ "type" : "mama" },
"properties" :
{ "project_id" : { "type" : "string", "index" : "not_analyzed" } }
}
}
}'
curl -XPOST "http://localhost:9200/_aliases" -d '
{ "actions":
[ { "add":
{ "alias": "family1",
"index": "famtest",
"routing": "100",
"filter":
{ "term": { "project_id": "100" } }
}
} ]
}'
curl -XPOST "http://localhost:9200/_aliases" -d '
{ "actions":
[ { "add":
{ "alias": "family2",
"index": "famtest",
"routing": "200",
"filter":
{ "term": { "project_id": "200" } }
}
} ]
}'
Now let's make some mamas:
curl -XPOST localhost:9200/family1/mama/1 -d '{ "name" : "Family 1 Mom", "project_id" : "100" }'
curl -XPOST localhost:9200/family2/mama/2 -d '{ "name" : "Family 2 Mom", "project_id" : "200" }'
These documents are now available via /familyX/_search. So now we want to add a baby:
curl -XPOST localhost:9200/family1/baby/1?parent=1 -d '{ "name": "Fam 1 Baby","project_id" : "100" }'
Unfortunately, ES doesn't like that:
{"error":"ElasticSearchIllegalArgumentException[Alias [family1] has index routing associated with it [100], and was provided with routing value [1], rejecting operation]","status":400}
So... any idea how to use alias routing and still set the parent id? If I understand this right, it shouldn't be a problem: all project operations ("family1", in this case) go through the alias, so parent and child docs will wind up on the same shard anyway. Is there some alternative way to set the parent id, without interfering with the routing?
Thanks. Please let me know if I can be more specific.

Answer 1

Interesting question! As you already know the parent id is used for routing too since children must be indexed in the same shard as the parent documents. What you're trying to do is fine, since parent and children would fall into the same family, thus in the same shard anyway since you configured the routing in the family alias.
But I'm afraid the parent id has higher priority than the routing defined in the alias, which gets overwritten, but that's not possible and that's why you get the error. In fact, if you try again providing the routing in your index request it works:
curl -XPOST 'localhost:9200/family1/baby/1?parent=1&routing=100' -d '{ "name": "Fam 1 Baby","project_id" : "100" }'
I would fill in a github issue with a curl recreation.