The JSON value could not be converted to Amazon.CodePipeline.ArtifactLocationType

[ingun37]

Description

DefaultLambdaJsonSerializer fails to decode payload coming from CodePipeline, specifically
$['CodePipeline.job'].data.inputArtifacts[0].location.type
to
Amazon.CodePipeline.ArtifactLocationType

Reproduction Steps

Define Lambda handler with type of Codepipeline payload

    public class CodePipelineEvent
    {
        [JsonPropertyName("CodePipeline.job")]
        public Amazon.CodePipeline.Model.Job job { get; set; }
    }
    public Task FunctionHandler(CodePipelineInput input, ILambdaContext context) { ... }

then test with an actual payload.

Logs

Error converting the Lambda event JSON payload to type BenchmarkingLoader.CodePipelineInput: The JSON value could not be converted to Amazon.CodePipeline.ArtifactLocationType. Path: $['CodePipeline.job'].data.inputArtifacts[0].location.type | LineNumber: 0 | BytePositionInLine: 258.: JsonSerializerException
   at Amazon.Lambda.Serialization.SystemTextJson.DefaultLambdaJsonSerializer.Deserialize[T](Stream requestStream)
   at lambda_method(Closure , Stream , Stream , LambdaContextInternal )

   at System.Text.Json.ThrowHelper.ThrowJsonException_DeserializeUnableToConvertValue(Type propertyType)
   at System.Text.Json.JsonPropertyInfoNotNullable`4.OnRead(ReadStack& state, Utf8JsonReader& reader)
   at System.Text.Json.JsonPropertyInfo.Read(JsonTokenType tokenType, ReadStack& state, Utf8JsonReader& reader)
   at System.Text.Json.JsonSerializer.ReadCore(JsonSerializerOptions options, Utf8JsonReader& reader, ReadStack& readStack)
   at System.Text.Json.JsonSerializer.ReadCore(Type returnType, JsonSerializerOptions options, Utf8JsonReader& reader)
   at System.Text.Json.JsonSerializer.ParseCore(ReadOnlySpan`1 utf8Json, Type returnType, JsonSerializerOptions options)
   at System.Text.Json.JsonSerializer.Deserialize[TValue](ReadOnlySpan`1 utf8Json, JsonSerializerOptions options)
   at Amazon.Lambda.Serialization.SystemTextJson.DefaultLambdaJsonSerializer.Deserialize[T](Stream requestStream)

Environment

    <PackageReference Include="Amazon.Lambda.Core" Version="1.1.0" />
    <PackageReference Include="Amazon.Lambda.Serialization.SystemTextJson" Version="2.0.1" />
    <PackageReference Include="AWSSDK.CodePipeline" Version="3.5.1.5" />
    <PackageReference Include="AWSSDK.S3" Version="3.5.5.2" />

Lambda

Resolution

---

This is a 🐛 bug-report

[ashishdhingra]

Hi @ingun37,

Good afternoon.

In order to troubleshoot the issue, please let me know the reference/guide from where CodePipelineEvent definition as determined. There appears to be some mismatched mapping that resulted in above exception. Also, is it possible for you to share a sample code solution?

In the meanwhile, I will try to investigate the issue.

Thanks,
Ashish

[ashishdhingra]

Hi @ingun37,

Upon examining it further, the cause of the error is that Amazon.CodePipeline.Model.ArtifactLocation.Type is of type ArtifactLocationType, whereas the type JSON property in the below example CodePipeline event input JSON is of type string:

{
  "CodePipeline.job": {
    "id": "c968ef10-6415-4127-80b1-42502218a8c7",
    "accountId": "123456789012",
    "data": {
      "actionConfiguration": {
        "configuration": {
          "FunctionName": "my-function",
          "UserParameters": "user-parameter-string"
        }
      },
      "inputArtifacts": [
        {
          "name": "input-artifact",
          "location": {
            "type": "S3",
            "s3Location": {
              "objectKey": "my-pipeline/input-artifact/jjmtQ59",
              "bucketName": "codepipeline-{region}-12345678901"
            }
          },
          "revision": "ca2bdeadbeef7d1932acb4977e08c803295d9896"
        }
      ],
      "outputArtifacts": [
        {
          "name": "output-artifact",
          "location": {
            "type": "S3",
            "s3Location": {
              "objectKey": "test-lambda/output-artifact/ggjsOC9",
              "bucketName": "codepipeline-{region}-12345678901"
            }
          },
          "revision": null
        }
      ],
      "artifactCredentials": {
        "accessKeyId": "AKIAIOSFODNN7EXAMPLE",
        "secretAccessKey": "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY",
        "sessionToken": "token"
      }
    }
  }
}

You might have to write full-fledged custom class for CodePipelineEvent (refer SQSEvent as an example) and/or custom JsonConverter which converts string to ArtifactLocationType type.

NOTE: Just for reference here, the CodePipeline AWS Lambda page mentions about example JSON event.

Please let me know if this works.

Thanks,
Ashish

[ingun37]

I ended up writing full-fledged class like you said although it would have been nicer if I hadn’t had to but I’m happy overall with the resolution.

Is it going to be fixed in the future?

[ashishdhingra]

Hi @ingun37,

The SDK Model class ArtifactLocationType is auto-generated. Hence, I do not see it to be fixed in near future. Basically its the problem with the CodePipeline returning string but model class expecting it of a certain type. Hence the problem with the serialization process from JSON. Unfortunately, these types of constant classes cannot be represented in JSON. The workaround as mentioned earlier, is to write custom class (which you implemented) and/or write custom JsonConverter.

Thanks,
Ashish