Value for field not found - AppSync AWS

Question

I'm currently using AppSync to query against a GSI. I've been able to successfully use this block of code in a Pipeline Resolver function, but I don't know why it is not working when I try to use it in a traditional resolver.

I'm currently getting a mapping template error:

{
  "data": {
    "units": null
  },
  "errors": [
    {
      "path": [
        "units"
      ],
      "data": null,
      "errorType": "MappingTemplate",
      "errorInfo": null,
      "locations": [
        {
          "line": 2,
          "column": 3,
          "sourceName": null
        }
      ],
      "message": "Value for field '$[version]' not found."
    }
  ]
}

I tried searching in the AWS docs but adding "version" to the GraphQL type didn't work.

I also tried this (even though I'm not using S3) AppSync S3Object retrieval And the docs: https://docs.aws.amazon.com/appsync/latest/devguide/troubleshooting-and-common-mistakes.html#mapping-template-errors

Here's the request mapping template:

#set($arg=$context.args)

    {
    "operation": "Query",
    "index" : "userPK-userSK-index",
    "query": {
        "expression": "userPK = :pk and begins_with(userSK, :sk)",
        "expressionValues": {
            ":pk": {"S": "tenant:${arg.tenantId}" },
            ":sk": {"S": "school-year:${arg.schoolYear}:grades:${arg.gradeId}:subject:${arg.subjectId}:unit:"}
        }
    }
}

Here's the response mapping template:

$util.toJson($ctx.result.items)

Here is a snippet of the executed GraphQL:

query GetUnits{
  units(tenantId: "5fc30406-346c-42e2-8083-fda33ab6000a"
schoolYear: "2019-2020"
    gradeId: "c737e341-a0cb-4a16-95de-f3a092049e74"
subjectId: "d0306e25-422d-4628-8fcc-c354b67c932a") {
  id
  indicator {
    id,
    description
  }
  competency {
    id,
    description,
    name
  }
  description,
  name
}


}

Here is a snippet of the GraphQL schema:


type Unit {
  id: ID!
  competency: Competency
  indicator: Indicator
  name: String!
  description: String
  version: Int
}

type Competency {
  id: ID
  # grade: Grade
  # subject: Subject
  # schoolYear: String
  name: String
  description: String
}

type Indicator { 
  id: ID!
  description: String
}
type Query {
  units(
    tenantId: String!
    schoolYear: String!
    gradeId: String!
    subjectId: String!
  ): [Unit]

Here's a data example from the DynamoDB table:

Here's a screenshot from a successful query in the Console:

Note: I have created a GSI that maps the userPK and userSK as partition key and sort key respectively. I'm querying that Secondary Index. I've been able to query this successfully using the console.

Pedro Arantes Pedro Arantes · Accepted Answer · 2019-08-27T06:34:28

The error shows you forgot version parameter. This is the query template (docs):

{
    "version" : "2017-02-28",
    "operation" : "Query",
    "query" : {
        "expression" : "some expression",
        "expressionNames" : {
            "#foo" : "foo"
        },
        "expressionValues" : {
            ":bar" : ... typed value
        }
    }
    "index" : "fooIndex",
    "nextToken" : "a pagination token",
    "limit" : 10,
    "scanIndexForward" : true,
    "consistentRead" : false,
    "select" : "ALL_ATTRIBUTES",
    "filter" : {
        ...
    }
}

and the version is required:

version

The template definition version. 2017-02-28 and 2018-05-29 are currently supported. This value is required.

Value for field not found - AppSync AWS

1 Answers