.NET Lambda on LocalStack throws "exception while calling lambda with unknown operation:"

ranga · September 12, 2024, 12:53pm

Hi,
I wanted to test a simple lambda function written in .NET on my localstack.
I’m using a docker compose file to run Localstack on my local windows machine.

version: "3.8"

services:
  localstack:
    container_name: "${LOCALSTACK_DOCKER_NAME:-localstack-main}"
    image: localstack/localstack
    ports:
      #- "127.0.0.1:4566:4566"            # LocalStack Gateway
      #- "127.0.0.1:4510-4559:4510-4559"  # external services port range
      - 4566:4566
    environment:
      # LocalStack configuration: https://docs.localstack.cloud/references/configuration/
      - SERVICES=s3,sql,lambda
      - LAMBDA_RUNTIME_ENVIRONMENT_TIMEOUT=50
      - AWS_DEFAULT_REGION=us-east-1
      - AWS_ENDPOINT= http://localstack:4566
      - DEBUG=${DEBUG:-1}
    volumes:
      - "${LOCALSTACK_VOLUME_DIR:-./volume}:/var/lib/localstack"
      - "/var/run/docker.sock:/var/run/docker.sock"

The .net code is as follows. (This is a very simple minimal API)

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
builder.Services.AddAWSLambdaHosting(LambdaEventSource.HttpApi);
var app = builder.Build();
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseHttpsRedirection();

app.MapGet("hello/", () => $"Hello");

app.Run();

I create the .zip file using folowing command

dotnet lambda package --configuration release --framework net8.0 --output-package releases/hellolambda.zip

and deployed to localstack using the following command

awslocal lambda create-function --function-name hellolambda --runtime dotnet8 --timeout 50 --zip-file fileb://releases/hellolambda.zip --handler hellolambda.handler --role arn:aws:iam::000000000000:role/lambda-role

so in order get access to the endpoint of my function, I create a lambda function url as stated in the following blog

 awslocal lambda create-function-url-config --function-name hellolambda --auth-type NONE

It resulted the following:

 {
    "FunctionUrl": "http://hq2cbj7kw7ag6zp8pidtvct0jwr7zyab.lambda-url.us-east-1.localhost.localstack.cloud:4566/",
    "FunctionArn": "arn:aws:lambda:us-east-1:000000000000:function:hellolambda",
    "AuthType": "NONE",
    "CreationTime": "2024-09-12T12:05:25.719615+0000"
}

When I try to access the above url from my browser. I got an error.

The error in plain text as spitted in the console

 Traceback (most recent call last):
localstack-main  |   File "/opt/code/localstack/localstack-core/localstack/services/lambda_/invocation/executor_endpoint.py", line 166, in wait_for_startup
localstack-main  |     self.startup_future.result()
localstack-main  |   File "/usr/local/lib/python3.11/concurrent/futures/_base.py", line 454, in result
localstack-main  |     raise CancelledError()
localstack-main  | concurrent.futures._base.CancelledError
localstack-main  |
localstack-main  | The above exception was the direct cause of the following exception:
localstack-main  |
localstack-main  | Traceback (most recent call last):
localstack-main  |   File "/opt/code/localstack/localstack-core/localstack/services/lambda_/invocation/execution_environment.py", line 198, in start
localstack-main  |     self.runtime_executor.start(self.get_environment_variables())
localstack-main  |   File "/opt/code/localstack/localstack-core/localstack/services/lambda_/invocation/docker_runtime_executor.py", line 430, in start
localstack-main  |     self.executor_endpoint.wait_for_startup()
localstack-main  |   File "/opt/code/localstack/localstack-core/localstack/services/lambda_/invocation/executor_endpoint.py", line 170, in wait_for_startup
localstack-main  |     raise ShutdownDuringStartup(
localstack-main  | localstack.services.lambda_.invocation.executor_endpoint.ShutdownDuringStartup: Executor environment shutdown during container startup
localstack-main  |
localstack-main  | The above exception was the direct cause of the following exception:
localstack-main  |
localstack-main  | Traceback (most recent call last):
localstack-main  |   File "/opt/code/localstack/.venv/lib/python3.11/site-packages/rolo/gateway/chain.py", line 166, in handle
localstack-main  |     handler(self, self.context, response)
localstack-main  |   File "/opt/code/localstack/.venv/lib/python3.11/site-packages/rolo/gateway/handlers.py", line 27, in __call__
localstack-main  |     router_response = self.router.dispatch(context.request)
localstack-main  |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
localstack-main  |   File "/opt/code/localstack/.venv/lib/python3.11/site-packages/rolo/router.py", line 381, in dispatch
localstack-main  |     return self.dispatcher(request, handler, args)
localstack-main  |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
localstack-main  |   File "/opt/code/localstack/.venv/lib/python3.11/site-packages/rolo/dispatcher.py", line 72, in _dispatch
localstack-main  |     result = endpoint(request, **args)
localstack-main  |              ^^^^^^^^^^^^^^^^^^^^^^^^^
localstack-main  |   File "/opt/code/localstack/localstack-core/localstack/services/lambda_/urlrouter.py", line 87, in handle_lambda_url_invocation
localstack-main  |     result = self.lambda_service.invoke(
localstack-main  |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^
localstack-main  |   File "/opt/code/localstack/localstack-core/localstack/services/lambda_/invocation/lambda_service.py", line 329, in invoke
localstack-main  |     return version_manager.invoke(
localstack-main  |            ^^^^^^^^^^^^^^^^^^^^^^^
localstack-main  |   File "/opt/code/localstack/localstack-core/localstack/services/lambda_/invocation/version_manager.py", line 196, in invoke
localstack-main  |     with self.assignment_service.get_environment(
localstack-main  |   File "/usr/local/lib/python3.11/contextlib.py", line 137, in __enter__
localstack-main  |     return next(self.gen)
localstack-main  |            ^^^^^^^^^^^^^^
localstack-main  |   File "/opt/code/localstack/localstack-core/localstack/services/lambda_/invocation/assignment.py", line 68, in get_environment
localstack-main  |     execution_environment = self.start_environment(version_manager_id, function_version)
localstack-main  |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
localstack-main  |   File "/opt/code/localstack/localstack-core/localstack/services/lambda_/invocation/assignment.py", line 97, in start_environment
localstack-main  |     execution_environment.start()
localstack-main  |   File "/opt/code/localstack/localstack-core/localstack/services/lambda_/invocation/execution_environment.py", line 212, in start
localstack-main  |     raise EnvironmentStartupTimeoutException(
localstack-main  | localstack.services.lambda_.invocation.execution_environment.EnvironmentStartupTimeoutException: Execution environment timed out during startup.
localstack-main  | 2024-09-12T12:08:59.108  INFO --- [et.reactor-4] localstack.request.http    : GET /hello/ => 500

Also note that, if I run the application on my localhost as a normal web-api deployment, I can access the endpoint and see the results on my browser.

Can someone help me to understand what is wrong with my deployment?
am I missing any configurations or am I not doing the things in correct order?
appreciate your help in this regard.

Regards

Marcel · September 17, 2024, 7:24am

Hi,

Here is a sample that I used to deploy the dotnet Lambda.
Please also have a look at localstack-dotnet/localstack-dotnet-client: A lightweight .NET client for LocalStack (github.com).

# https://docs.aws.amazon.com/lambda/latest/dg/csharp-package-cli.html
# https://docs.aws.amazon.com/toolkit-for-visual-studio/latest/user-guide/lambda-cli-publish.html
# https://learn.microsoft.com/en-us/dotnet/core/rid-catalog
# https://stackoverflow.com/questions/66551987/how-to-run-aws-lambda-dotnet-on-localstack
# https://docs.localstack.cloud/user-guide/integrations/aws-cli/

# Install Lambda templates and tools
dotnet new install Amazon.Lambda.Templates
dotnet tool install -g Amazon.Lambda.Tools

# Create a new Lambda project
dotnet new lambda.EmptyFunction --name myDotnetFunction

# Change to the project directory
Set-Location myDotnetFunction\src\myDotnetFunction

# Restore the project dependencies
dotnet restore

# Build the project
dotnet build
dotnet publish -c Release -o publish

# Change to the publish directory
Set-Location publish

# Create a zip file of the project
Compress-Archive -Path * -DestinationPath myDotnetFunction.zip

awslocal lambda create-function `
    --function-name myDotnetFunction `
    --runtime dotnet8 `
    --role arn:aws:iam::000000000000:role/lambda-role `
    --handler myDotnetFunction::myDotnetFunction.Function::FunctionHandler `
    --zip-file fileb://myDotnetFunction.zip `
    --region us-east-1

# Invoke the Lambda function
awslocal lambda invoke --function-name myDotnetFunction --payload '"Hello, world!"' output.json

Adding a bit of different approach:

# Prerequisites:
# 1. .NET SDK installed (https://dotnet.microsoft.com/download)
# 2. AWS CLI installed and configured (https://docs.aws.amazon.com/cli/latest/userguide/install-cliv2.html)
# 3. LocalStack installed and running (https://docs.localstack.cloud/getting-started/)
# 4. Amazon.Lambda.Tools installed (dotnet tool install -g Amazon.Lambda.Tools)
# 5. Amazon.Lambda.Templates installed (dotnet new install Amazon.Lambda.Templates)

# https://docs.aws.amazon.com/lambda/latest/dg/csharp-package-cli.html
# https://docs.aws.amazon.com/toolkit-for-visual-studio/latest/user-guide/lambda-cli-publish.html
# https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-endpoints.html

# Install Lambda templates and tools
dotnet new install Amazon.Lambda.Templates
dotnet tool install -g Amazon.Lambda.Tools

# Create a new Lambda project
dotnet new lambda.EmptyFunction --name myDotnetFunction

# Change to the project directory
Push-Location -Path "myDotnetFunction/src/myDotnetFunction"

# Set environment variables for LocalStack
$env:AWS_ENDPOINT_URL = "http://localhost.localstack.cloud:4566"
$env:AWS_ACCESS_KEY_ID = "test"
$env:AWS_SECRET_ACCESS_KEY = "test"
$env:AWS_DEFAULT_REGION = "us-east-1"

# Deploy the Lambda function
dotnet lambda deploy-function `
    --use-container-for-build $true `
    --function-role "arn:aws:iam::000000000000:role/lambda-role" `
    --function-name "myDotnetFunction" `
    --framework "net8.0" `
    --function-architecture "x86_64" `
    --environment-variables "TEST_VAR=TEST_VAL1"

# Invoke the Lambda function
dotnet lambda invoke-function "myDotnetFunction" --payload '"Hello, world!"'

# Return to the previous directory
Pop-Location

ranga · September 17, 2024, 1:06pm

Thank you very much for the links and the steps. I’ll try this and share the outcome.

Topic		Replies	Views
Running Lambda in localstack container, not it's own container Platform	2	57	November 6, 2024
I can't run Lambda in LocalStack Platform localstack	1	1540	July 19, 2023
Running Lambda in localstack inside a k8s strucutre Platform localstack	7	625	January 22, 2024
Creating Lambda Function Platform localstack	1	389	May 8, 2023
Remote Debugging Dotnet Lambdas localstack	1	488	October 24, 2022

.NET Lambda on LocalStack throws "exception while calling lambda with unknown operation:"

Related topics