mschleskegogo / ddbhelper

You made me do this, Bezos.

Usage

Create a test event in the AWS console with either a queryParams or a scanParams field containing the AWS parameters to feed into the query or scan operation. If both fields exist, the query will be used and the scan will be ignored.

Optionally, a dataHandler field may also be defined in the test event. The value of this field must be a stringified javascript function that takes a single data parameter. If the scan or query succeeds, the results will be passed into the dataHandler function. If the dataHandler function returns any results, they will be returned in the lambda response. The default dataHandler simply returns the results of the DynamoDB operation.

Note: because this is a JSON string, it cannot contain newlines and must be flattened to a single line (an example of this is shown below).

Example:

{
  "queryParams": {
    "TableName": "gogo-dash-int-persist-dev-aircraftevents",
    "KeyConditionExpression": "#P = :pvalue AND begins_with(#S, :svalue)",
    "FilterExpression": "attribute_exists(CONSOLE)",
    "ExpressionAttributeNames": {
      "#P": "aircraftSID",
      "#S": "eventKey"
    },
    "ExpressionAttributeValues": {
      ":pvalue": "001F0000010HrN5IAK:a01F000000F2UBPIA3",
      ":svalue": "15913"
    }
  },
  "dataHandler": "data => {return data.Items.reduce((acc, item) => {if (item.CONSOLE.flight_state === 'ABOVE_SERVICE_ALTITUDE') {acc.ASA++} else {acc.BSA++}return acc},{ ASA: 0, BSA: 0 })}"
}

This sample test event will query the gogo-dash-int-persist-dev-aircraftevents table for records with

• A partition key matching 001F0000010HrN5IAK:a01F000000F2UBPIA3
• A sort key beginning with 15913
• A defined CONSOLE field

If matching records are found, the dataHandler function will count and return the number of records whose CONSOLE.flight_state is or is not ABOVE_SERVICE_ALTITUDE.

The result of running the lambda with this test event would look something like this:

{
  "ASA": 26,
  "BSA": 5
}

Here is the same dataHandler before flattening:

data => {
  return data.Items.reduce(
    (acc, item) => {
      if (item.CONSOLE.flight_state === 'ABOVE_SERVICE_ALTITUDE') {
        acc.ASA++
      } else {
        acc.BSA++
      }
      return acc
    },
    { ASA: 0, BSA: 0 }
  )
}