DynamoDB events have milliseconds, not seconds, in their timestamps which crashes deserialization

[cdegroot]

Description

I'm creating a lambda to process DynamoDB events streamed through Kinesis, which means they're wrapped in base64, etcetera. During processing I pull them out and then deserialize them to DynamoDBv2 records:

            var serializer = new Amazon.Lambda.Serialization.Json.JsonSerializer();
            var dynamoEvent = serializer.Deserialize<Amazon.DynamoDBv2.Model.Record>(BaseObserver.GenerateStreamFromString(dynamoData));

Reproduction Steps

This gist: https://gist.github.com/cdegroot/6e8e1957d9d08a595b3918dce3e16d84. Note that all I did was to add a couple of zeros to the test event.

Logs

Stacktrace:

  X TestDynamoParsing [8ms]
  Error Message:
   Test method Canary.EventStore.Tests.BaseObserverTests.TestDynamoParsing threw exception: 
Amazon.Lambda.Serialization.Json.JsonSerializerException: Error converting the Lambda event JSON payload to type Amazon.DynamoDBv2.Model.Record: Value to add was out of range. (Parameter 'value') ---> System.ArgumentOutOfRangeException: Value to add was out of range. (Parameter 'value')                                                                                    
  Stack Trace:
      at System.DateTime.Add(Double value, Int32 scale)
   at System.DateTime.AddSeconds(Double value)
   at Amazon.Lambda.Serialization.Json.JsonNumberToDateTimeDataConverter.ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.DeserializeConvertable(JsonConverter converter, JsonReader reader, Type objectType, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(JsonProperty property, JsonConverter propertyConverter, JsonContainerContract containerContract, JsonProperty containerProperty, JsonReader reader, Object target)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(Object newObject, JsonReader reader, JsonObjectContract contract, JsonProperty member, String id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(JsonProperty property, JsonConverter propertyConverter, JsonContainerContract containerContract, JsonProperty containerProperty, JsonReader reader, Object target)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(Object newObject, JsonReader reader, JsonObjectContract contract, JsonProperty member, String id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent)
   at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType)
   at Newtonsoft.Json.JsonSerializer.Deserialize(JsonReader reader, Type objectType)
   at Newtonsoft.Json.JsonSerializer.Deserialize[T](JsonReader reader)
   at Amazon.Lambda.Serialization.Json.JsonSerializer.Deserialize[T](Stream requestStream)
--- End of inner exception stack trace ---
    at Amazon.Lambda.Serialization.Json.JsonSerializer.Deserialize[T](Stream requestStream

Environment

• Build Version: 1.2.0
• OS Info: Ubuntu 20.10
• Build Environment: Terminal dotnet test etc.
• Targeted .NET Platform: 3.1

Resolution

• 👋 I can/would-like-to implement a fix for this problem myself

I can look later, will just kill the last three digits with a regex for now, but the usual fix is to take a cut-off value (100000000000 - somewhere in the 6th millenium) and if it's above, interpret as millisecs, if not, as secs.

Of course, the proper fix is to make DynamoDB emit always one or the other :)

---

This is a 🐛 bug-report

[ashishdhingra]

Hi @cdegroot,

Good afternoon.

Looking at the code, looks like it is an automated unit test code where your test data is real record from DynamoDB Streams. Could you please share the source for the JSON string? In you JSON string, the value for ApproximateCreationDateTime is 1480642020000. However, the example at https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Streams.Lambda.Tutorial.html, has value 1479499740 for example. Notice the extra last 3 digits, as pointed by you as well. Not sure if there is an issue with your test data. While I didn't got a chance to examine the actual event received from DynamoDB stream, just wanted to validate your test data.

Thanks,
Ashish

[cdegroot]

I created that test based on real data I saw flowing so I could reproduce (and work around the issue). I won't share our full data in public, but hopefully the following exposition helps.

From another (JS-based) Kinesis consumer, which is logging full Kinesis events, I copied an event:

var kinesisData = @"{""Records"":[{""kinesis"":{""kinesisSchemaVersion"":""1.0"",""partitionKey"":""D7FE246F3E699C3B143D2A8378D17223"",""sequenceNumber"":""49616371596847055066813995925388293329944250222301413394"",""data"":""eyJhd3....1vZGIifQ=="",""approximateArrivalTimestamp"":1616427312.824},""eventSource"":""aws:kinesis"",""eventVersion"":""1.0"",""eventID"":""shardId-000000000001:49616371596847055066813995925388293329944250222301413394"",""eventName"":""aws:kinesis:record"",""invokeIdentityArn"":""arn:aws:iam::..."",""awsRegion"":""us-east-1"",""eventSourceARN"":""arn:aws:kinesis:us-east-1:147803588724:stream...""}]}";

I snipped most of the payload for brevity and privacy, but base64 decoding it:

{
  "awsRegion": "us-east-1",
  "dynamodb": {
    "ApproximateCreationDateTime": 1616427312786,
    "Keys": {
      "Id": {
        "S": "SHARED/User/0gKQCSqc3bQUW90Fch6oCv"
      },
      "Version": {
        "N": "1"
      }
    },
    "NewImage": {
      "Event": {
        "S": "..."
      },
      "Version": {
        "N": "1"
      },
      "Id": {
        "S": "SHARED/User/0gKQCSqc3bQUW90Fch6oCv"
      },
      "Type": {
        "S": "InviteDeleted"
      }
    },
    "SizeBytes": 452
  },
  "eventID": "408c266f-06b0-43e6-9e31-68f530664e6c",
  "eventName": "INSERT",
  "userIdentity": null,
  "recordFormat": "application/json",
  "tableName": "dev1-EventLog",
  "eventSource": "aws:dynamodb"
}

(again edited for brevity and privacy). As you can see, there's a 13 digit timestamp in there. I added three zeroes to the existing test data (which I think I snipped from here] to reproduce the issue.

[ashishdhingra]

Hi @cdegroot,

Good afternoon.

Unfortunately I'm unable to reproduce the issue. Used the below steps:

1. Created DynamoDb table HighScoresWithStream with:

• Username (String) as Primary partition key and Game (String) as Primary sort key
• DynamoDB stream enabled (View type as New and old images)

2. Created the following Lambda function:
   .csproj

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <GenerateRuntimeConfigurationFiles>true</GenerateRuntimeConfigurationFiles>
    <AWSProjectType>Lambda</AWSProjectType>

    <!-- This property makes the build directory similar to a publish directory and helps the AWS .NET Lambda Mock Test Tool find project dependencies. -->
    <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Amazon.Lambda.Core" Version="2.0.0" />
    <PackageReference Include="Amazon.Lambda.DynamoDBEvents" Version="2.0.0" />
    <PackageReference Include="Amazon.Lambda.Serialization.SystemTextJson" Version="2.1.0" />
  </ItemGroup>
</Project>

Function.cs

using Amazon.Lambda.Core;
using System.IO;

// Assembly attribute to enable the Lambda function's JSON input to be converted into a .NET class.
[assembly: LambdaSerializer(typeof(Amazon.Lambda.Serialization.SystemTextJson.DefaultLambdaJsonSerializer))]

namespace DynamoDbStream_Issue839
{
    public class Function
    {
        public void FunctionHandler(DynamoDBEvent dynamoDBEvent, ILambdaContext context)
        {
            context.Logger.LogLine($"DynamoDBEvent received with {dynamoDBEvent.Records.Count} records.");
            foreach (var record in dynamoDBEvent.Records)
            {
                context.Logger.LogLine($"{record.EventID}:{record.EventName}, Dynamodb.ApproximateCreationDateTime:{record.Dynamodb.ApproximateCreationDateTime}");
            }
        }
    }
}

aws-lambda-tools-defaults.json

{
    "Information" : [
        "This file provides default values for the deployment wizard inside Visual Studio and the AWS Lambda commands added to the .NET Core CLI.",
        "To learn more about the Lambda commands with the .NET Core CLI execute the following command at the command line in the project root directory.",
        "dotnet lambda help",
        "All the command line options for the Lambda command can be specified in this file."
    ],
    "profile"     : "default",
    "region"      : "us-east-2",
    "configuration" : "Release",
    "framework"     : "netcoreapp3.1",
    "function-runtime" : "dotnetcore3.1",
    "function-memory-size" : 256,
    "function-timeout"     : 30,
    "function-handler"     : "DynamoDbStream_Issue839::DynamoDbStream_Issue839.Function::FunctionHandler",
    "function-name"        : "StreamConsumer",
    "package-type"         : "Zip",
    "function-role"        : "arn:aws:iam::139480602983:role/lambda_exec_StreamConsumer-0",
    "tracing-mode"         : "PassThrough",
    "environment-variables" : "",
    "image-tag"             : "",
    "function-description"  : ""
}

NOTE: To keep things simple for reproduction, the role lambda_exec_StreamConsumer-0 has AWSLambdaExecute and AmazonDynamoDBFullAccess policies attached.

3. Published the Lambda function to AWS.
4. In AWS Lambda console, added DynamoDB trgigger for table HighScoresWithStream
5. Added some records to DynamoDB database.
6. Examined the CloudWatch logs:

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|   timestamp   |                                                                                                                                              message                                                                                                                                               |
|---------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 1617405537095 | START RequestId: 4c7331ac-6882-449b-8488-e78994536976 Version: $LATEST                                                                                                                                                                                                                             |
| 1617405537203 | DynamoDBEvent received with 1 records.                                                                                                                                                                                                                                                             |
| 1617405537282 | 1d507e4abd270fc658c78593be3ad773:INSERT, Dynamodb.ApproximateCreationDateTime:4/2/2021 11:18:18 PM                                                                                                                                                                                                 |
| 1617405537300 | END RequestId: 4c7331ac-6882-449b-8488-e78994536976                                                                                                                                                                                                                                                |
| 1617405537300 | REPORT RequestId: 4c7331ac-6882-449b-8488-e78994536976 Duration: 202.58 ms Billed Duration: 203 ms Memory Size: 256 MB Max Memory Used: 70 MB                                                                                                                                                      |
| 1617405565785 | START RequestId: 5bbf64d3-7f10-437d-bd00-4185c5b3c8fe Version: $LATEST                                                                                                                                                                                                                             |
| 1617405565790 | DynamoDBEvent received with 1 records.                                                                                                                                                                                                                                                             |
| 1617405565790 | 421616e0bcb058e190f341ed8227f4e5:INSERT, Dynamodb.ApproximateCreationDateTime:4/2/2021 11:19:25 PM                                                                                                                                                                                                 |
| 1617405565790 | END RequestId: 5bbf64d3-7f10-437d-bd00-4185c5b3c8fe                                                                                                                                                                                                                                                |
| 1617405565790 | REPORT RequestId: 5bbf64d3-7f10-437d-bd00-4185c5b3c8fe Duration: 3.31 ms Billed Duration: 4 ms Memory Size: 256 MB Max Memory Used: 70 MB                                                                                                                                                                                                                                                                                                                   |
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

7. Modified the code in Function.cs to below to capture JSON:

using Amazon.Lambda.Core;
using System.IO;

// Assembly attribute to enable the Lambda function's JSON input to be converted into a .NET class.
[assembly: LambdaSerializer(typeof(Amazon.Lambda.Serialization.SystemTextJson.DefaultLambdaJsonSerializer))]

namespace DynamoDbStream_Issue839
{
    public class Function
    {
        public Stream FunctionHandler(Stream userInput, ILambdaContext context)
        {
            string jsonString;
            using (var reader = new StreamReader(userInput))
            {
                jsonString = reader.ReadToEnd();
            }

            context.Logger.LogLine($"JSON received: {jsonString}");

            byte[] bytes = System.Text.Encoding.UTF8.GetBytes(jsonString);
            MemoryStream stream = new MemoryStream(bytes);
            return stream;
        }
    }
}

8. Republished the Lambda.
9. Added record to DynamoDB table.
10. Examined the CloudWatch logs:

JSON received: 
{
    "Records": [
        {
            "eventID": "1416c843df272af3718f3173fb9b0363",
            "eventName": "INSERT",
            "eventVersion": "1.1",
            "eventSource": "aws:dynamodb",
            "awsRegion": "us-east-2",
            "dynamodb": {
                "ApproximateCreationDateTime": 1617406031,
                "Keys": {
                    "Game": {
                        "S": "testgame"
                    },
                    "Username": {
                        "S": "multiple"
                    }
                },
                "NewImage": {
                    "Game": {
                        "S": "testgame"
                    },
                    "Username": {
                        "S": "multiple"
                    }
                },
                "SequenceNumber": "5800000000005804693158",
                "SizeBytes": 56,
                "StreamViewType": "NEW_AND_OLD_IMAGES"
            },
            "eventSourceARN": "arn:aws:dynamodb:us-east-2:139480602983:table/HighScoresWithStream/stream/2021-04-02T22:37:03.187"
        }
    ]
}

As you could see from JSON captured above, the ApproximateCreationDateTime has value with 10 digits (not 13 digits).

Please let me know if this helps.

Thanks,
Ashish

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