Odd query investigation

[kennethmorton]

This fails to return results through the ARS, but can return results when sent to ARAX directly. Please investigate

{
  "workflow": [
    {
      "id": "fill"
    },
    {
      "id": "bind"
    },
    {
      "id": "score"
    }
  ],
  "message": {
    "query_graph": {
      "edges": {
        "e0": {
          "constraints": [],
          "object": "n1",
          "predicates": ["biolink:related_to"],
          "subject": "n0"
        },
        "e1": {
          "constraints": [],
          "object": "n2",
          "predicates": ["biolink:genetically_interacts_with"],
          "subject": "n1"
        },
        "e2": {
          "constraints": [],
          "object": "n2",
          "predicates": ["biolink:affects", "biolink:correlated_with"],
          "subject": "n3"
        },
        "e3": {
          "constraints": [],
          "object": "n4",
          "predicates": ["biolink:related_to"],
          "subject": "n3"
        },
        "e4": {
          "constraints": [],
          "object": "n5",
          "predicates": ["biolink:related_to"],
          "subject": "n2"
        }
      },
      "nodes": {
        "n0": {
          "categories": ["biolink:BiologicalProcess"],
          "constraints": [],
          "ids": ["GO:0022010", "UMLS:C1818586"],
          "is_set": false,
          "name": "central nervous system myelination"
        },
        "n1": {
          "categories": ["biolink:Gene", "biolink:Protein"],
          "constraints": [],
          "is_set": true
        },
        "n2": {
          "categories": ["biolink:Gene", "biolink:Protein"],
          "constraints": [],
          "is_set": true
        },
        "n3": {
          "categories": ["biolink:SmallMolecule"],
          "constraints": [],
          "ids": [
            "CHEMBL.COMPOUND:CHEMBL134342",
            "CHEMBL.COMPOUND:CHEMBL1431",
            "CHEMBL.COMPOUND:CHEMBL573",
            "CHEMBL.COMPOUND:CHEMBL1626",
            "CHEMBL.COMPOUND:CHEMBL741",
            "CHEMBL.COMPOUND:CHEMBL1068",
            "CHEMBL.COMPOUND:CHEMBL1428",
            "CHEMBL.COMPOUND:CHEMBL30008"
          ],
          "is_set": false
        },
        "n4": {
          "categories": ["biolink:Disease"],
          "constraints": [],
          "is_set": false
        },
        "n5": {
          "categories": ["biolink:Disease"],
          "constraints": [],
          "is_set": false
        }
      }
    }
  }
}

[kennethmorton]

This is almost certainly failing due to the way we currently call only 1 service for a given operation. Resolving #12 will also hopefully resolve this issue.