Error: "Cant find [Assembly].deps.json" (but it exists)

[SeanKilleen]

Hi all,

Newer to AWS & Lambdas but I think I may have come across a problem. Hoping it's something I'm doing.

Setup / Versions

• I have an API gateway that proxies to a Lambda whose code is storied in an S3 bucket for the code -- api gateway, lambda, and bucket deployed via terraform
• The API gateway references a code.zip file in the S3 bucket.
• I am using the dotnet global tool "amazon.lambda.tools" v5.1.0
• I am using aws cli v2.1.29

Description

Reproduction Steps

• Created a new web API project: dotnet new serverless.AspNetCoreWebAPI
• Updated the handler function in the API gateway to match that specified in the project that is created above
• Run dotnet restore, dotnet build
• Run dotnet lambda package code.zip
• Verified that [AssemblyName].deps.json exists at the root of the zip file.
• Upload the zip file to the S3 bucket that feeds the API gateway lambda
• Test the API via the management console

Expected behavior: see the default response for the /api/values route
Actual behavior: See an error: "Could not find the required 'LbsApi.deps.json'. This file should be present at the root of the deployment package." (this file is in the root of the zip file).

Environment

• Build Version: Amazon.Lambda.AspNetCoreServer v5.3.1
• Dotnet global tool: amazon.lambda.tools v5.1.0
• OS Info: Windows 10
• Build Environment: Terminal dotnet
• Targeted .NET Platform: netcoreapp3.1

Resolution

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

---

This is a 🐛 bug-report

[SeanKilleen]

Note: I've checked the solution in #243. In that case, the namespace and assembly name seemed to be different. In my case, the assembly and the namespace share the same name, LbsApi.

I have also attempted this running dotnet publish -C release to ensure I've got everything I need in the appropriate directory.

[SeanKilleen]

Logs from dotnet lambda package code.zip from within the project directory:

Amazon Lambda Tools for .NET Core applications (5.1.0)
Project Home: https://github.com/aws/aws-extensions-for-dotnet-cli, https://github.com/aws/aws-lambda-dotnet

Executing publish command
Deleted previous publish folder
... invoking 'dotnet publish', working folder 'C:\Users\skilleen\Repositories\[redacted]-api\src\LbsApi\bin\Release\netcoreapp3.1\publish'
... dotnet publish --output "C:\Users\skilleen\Repositories\[redacted]-api\src\LbsApi\bin\Release\netcoreapp3.1\publish" --configuration "Release" --framework "netcoreapp3.1" /p:GenerateRuntimeConfigurationFiles=true --runtime linux-x64 --self-contained false 
... publish: Microsoft (R) Build Engine version 16.9.0+57a23d249 for .NET
... publish: Copyright (C) Microsoft Corporation. All rights reserved.
... publish:   Determining projects to restore...
... publish:   All projects are up-to-date for restore.
... publish:   LbsApi -> C:\Users\skilleen\Repositories\[redacted]-api\src\LbsApi\bin\Release\netcoreapp3.1\linux-x64\LbsApi.dll
... publish:   LbsApi -> C:\Users\skilleen\Repositories\[redacted]-api\src\LbsApi\bin\Release\netcoreapp3.1\publish\
Zipping publish folder C:\Users\skilleen\Repositories\[redacted]-api\src\LbsApi\bin\Release\netcoreapp3.1\publish to C:\Users\skilleen\Repositories\[redacted]-api\src\LbsApi\code.zip
... zipping: Amazon.Lambda.APIGatewayEvents.dll
... zipping: Amazon.Lambda.ApplicationLoadBalancerEvents.dll
... zipping: Amazon.Lambda.AspNetCoreServer.dll
... zipping: Amazon.Lambda.Core.dll
... zipping: Amazon.Lambda.Logging.AspNetCore.dll
... zipping: Amazon.Lambda.Serialization.SystemTextJson.dll
... zipping: appsettings.Development.json
... zipping: appsettings.json
... zipping: aws-lambda-tools-defaults.json
... zipping: LbsApi
... zipping: LbsApi.deps.json
... zipping: LbsApi.dll
... zipping: LbsApi.pdb
... zipping: LbsApi.runtimeconfig.json
... zipping: web.config
Created publish archive (C:\Users\skilleen\Repositories\[redacted]-api\src\LbsApi\code.zip).
Lambda project successfully packaged: C:\Users\skilleen\Repositories\[redacted]-api\src\LbsApi\code.zip

[SeanKilleen]

In reviewing some older threads elsewhere, e.g. https://forums.aws.amazon.com/thread.jspa?threadID=285087, it sounds like this may be related to a permissions issue and not to the missing file.

If anyone here knows of a way that I can diagnose/confirm this issue in my case, I'd greatly appreciate it. I'll begin digging into permissions in the interim.

[SeanKilleen]

This is looking like more of a red herring error related to permissions.

If this proven to be the case, I'd be happy to work on improving the error handling if someone could point me to the repository that contains the logic that raises this error. Thanks!

[SeanKilleen]

As an attempt to remove permissions from the equation, I have granted AWSLambda_FullAccess and AmazonS3FullAccess to the role that my Lambda is using. The problem appears to persist (it is also unclear to me if the lambda deployment might be cached somewhere that I need to bust.)

[ashishdhingra]

Hi @SeanKilleen,

Good afternoon.

Unfortunately, I'm unable to reproduce the issue. Here are the steps:

1. Installed latest version of Amazon.Lambda.Tools using command dotnet tool install -g Amazon.Lambda.Tools or dotnet tool update -g Amazon.Lambda.Tools.
2. Installed .NET CLI templates using command dotnet new -i Amazon.Lambda.Templates.
3. Created new serverless project using command dotnet new -i Amazon.Lambda.Templates.
4. Executed command dotnet lambda package code.zip from the project root directory.

Amazon Lambda Tools for .NET Core applications (5.1.1)
Project Home: https://github.com/aws/aws-extensions-for-dotnet-cli, https://github.com/aws/aws-lambda-dotnet

Executing publish command
Deleted previous publish folder
... invoking 'dotnet publish', working folder 'D:\Users\<<user>>\source\repros\ServerlessWebAPI_Issue854\src\ServerlessWebAPI_Issue854\bin\Release\netcoreapp3.1\publish'
... dotnet publish --output "D:\Users\<<user>>\source\repros\ServerlessWebAPI_Issue854\src\ServerlessWebAPI_Issue854\bin\Release\netcoreapp3.1\publish" --configuration "Release" --framework "netcoreapp3.1" /p:GenerateRuntimeConfigurationFiles=true --runtime linux-x64 --self-contained false
... publish: Microsoft (R) Build Engine version 16.9.0+57a23d249 for .NET
... publish: Copyright (C) Microsoft Corporation. All rights reserved.
... publish:   Determining projects to restore...
... publish:   All projects are up-to-date for restore.
... publish:   ServerlessWebAPI_Issue854 -> D:\Users\<<user>>\source\repros\ServerlessWebAPI_Issue854\src\ServerlessWebAPI_Issue854\bin\Release\netcoreapp3.1\linux-x64\ServerlessWebAPI_Issue854.dll
... publish:   ServerlessWebAPI_Issue854 -> D:\Users\<<user>>\source\repros\ServerlessWebAPI_Issue854\src\ServerlessWebAPI_Issue854\bin\Release\netcoreapp3.1\publish\
Zipping publish folder D:\Users\<<user>>\source\repros\ServerlessWebAPI_Issue854\src\ServerlessWebAPI_Issue854\bin\Release\netcoreapp3.1\publish to D:\Users\<<user>>\source\repros\ServerlessWebAPI_Issue854\src\ServerlessWebAPI_Issue854\code.zip
... zipping: Amazon.Lambda.APIGatewayEvents.dll
... zipping: Amazon.Lambda.ApplicationLoadBalancerEvents.dll
... zipping: Amazon.Lambda.AspNetCoreServer.dll
... zipping: Amazon.Lambda.Core.dll
... zipping: Amazon.Lambda.Logging.AspNetCore.dll
... zipping: Amazon.Lambda.Serialization.SystemTextJson.dll
... zipping: appsettings.Development.json
... zipping: appsettings.json
... zipping: aws-lambda-tools-defaults.json
... zipping: ServerlessWebAPI_Issue854
... zipping: ServerlessWebAPI_Issue854.deps.json
... zipping: ServerlessWebAPI_Issue854.dll
... zipping: ServerlessWebAPI_Issue854.pdb
... zipping: ServerlessWebAPI_Issue854.runtimeconfig.json
... zipping: web.config
Created publish archive (D:\Users\<<user>>\source\repros\ServerlessWebAPI_Issue854\src\ServerlessWebAPI_Issue854\code.zip).
Lambda project successfully packaged: D:\Users\<<user>>\source\repros\ServerlessWebAPI_Issue854\src\ServerlessWebAPI_Issue854\code.zip

This creates code.zip in project's root directory. Also the ZIP file contains ServerlessWebAPI_Issue854.deps.json.

5. Logged in to AWS account.
6. Navigate to S3 bucket in the region (us-east-2 in my case) and uploaded code.zip to S3 bucket. Copied the Object URL for uploaded file.
7. Creating the lambda in AWS: Navigated to Lambda console and selected create function.

• Selected option Author from scratch.
• Function name as TestAPIFunction.
• Runtime as .NET Core 3.1 (C#/PowerShell)
• After function is created, in the Code table, click Upload from and select Amazon S3 location.
• Specify the copied Object URL from step 6.
• Click Save.
• In the Lambda Runtime settings, click Edit and specify the correct value for Handler (this could be found from serverless.template.

7. Creating the API Gateway:

• Navigate to API Gateway console.
• Under REST API, click Build.
• Specify API name and click Create API.
• In Resources tab, click on Actions menu and select Create Resource.
• In New Child Resource page, Check the box Configure as proxy resource and click on Create Resource.
• Complete the setup by selecting the lambda function.
• From Actions menu, click Deploy API. (NOTE: During deployment, it displayed message that it would grant API gateway permissions)
• Take note of Invoke URL (e.g. https://ifzutkbmkd.execute-api.us-east-2.amazonaws.com/example)

8. Invoke the endpoint:

• Open the Invoke URL in web browser and navigate to Invoke URL (copied from previous step). It displays error {"message":"Missing Authentication Token"}.
• Append the URL with and endpoint from the template /api/values. This displays ["value1","value2"] in the browser.

Reference article: https://codingwithsam.com/posts/getting-started-.NET-AWS-lambda/

Hope this helps. I'm not sure about your Terraform template, there are articles on the internet which might provide some guidance.

Thanks,
Ashish

[SeanKilleen]

@ashishdhingra I appreciate you looking into this. I discovered recently that this was my fault. I wrote a response to this thread but must not have posted it somehow.

The issue was indeed in my end, in terms of conceptualizing how Lambda deployment works in AWS. I discovered that the source code size for the lambda was listed as 140 bytes which raised some flags as you might imagine.

The misunderstanding on my part was that when deploying the lambda via Terraform, we'd had to set a bucket and a file location for the code. This led me to think that updating the file would be enough to trigger the deployment. However, it's completely reasonable that we'd need to specifically point the lambda to a new source file, even if that file is an updated file in the same location.

So, a tough lesson learned, but I appreciate your thorough response -- thank you! Closing this issue.