Unreal Engine aws-sdk for linux compile issue

[GabrieliusD]

Hello,

I am trying to implement aws-sdk to unreal engine as a plugin for a linux server, I was successful at implementing it for windows but I'm having issues when trying to use Aws::Utils::Json::JsonValue which gives me the following error:

Severity	Code	Description	Project	File	Line	Suppression State
Error		undefined symbol: Aws::Utils::Json::JsonValue::WithString(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)	
..\Intermediate\ProjectFiles\ld.lld	1	

Severity	Code	Description	Project	File	Line	Suppression State
Error		undefined symbol: Aws::Utils::Json::JsonView::WriteReadable(bool) const	
..\Intermediate\ProjectFiles\ld.lld	1	

Severity	Code	Description	Project	File	Line	Suppression State
Error		linker command failed with exit code 1 (use -v to see invocation)	
..\Intermediate\ProjectFiles\clang++	1	

I have build the sdk on wsl using cmake with the following command:
cmake ../aws-sdk-cpp -DCMAKE_BUILD_TYPE=Debug -DCMAKE_PREFIX_PATH=/usr/local/ -DCMAKE_INSTALL_PREFIX=/usr/local/ -DBUILD_ONLY="s3;lambda;dynamodb" -DBUILD_SHARED_LIBS=ON -DCUSTOM_MEMORY_MANAGEMENT=OFF

AWSSDK.Build.cs file tells where to find the lib files:

public class AWSSDK : ModuleRules
{
    // list every library you plan to use here
    private List<string> LinuxLibraryNames = new List<string>()
    {
        "libaws-cpp-sdk-access-management.so",
        "libaws-cpp-sdk-cognito-identity.so",
        "libaws-cpp-sdk-core.so",
        "libaws-cpp-sdk-iam.so",
        "libaws-cpp-sdk-kinesis.so",
        "libaws-cpp-sdk-lambda.so",
        "libaws-cpp-sdk-dynamodb.so",
        "libaws-cpp-sdk-s3.so",
        "libtesting-resources.so"
    };
    private List<string> LibraryNames = new List<string>()
    {
        "aws-c-auth",
        "aws-c-cal",
        "aws-c-common",
        "aws-c-compression",
        "aws-c-event-stream",
        "aws-checksums",
        "aws-c-http",
        "aws-c-io",
        "aws-c-mqtt",
        "aws-cpp-sdk-access-management",
        "aws-cpp-sdk-cognito-identity",
        "aws-cpp-sdk-core",
        "aws-cpp-sdk-iam",
        "aws-cpp-sdk-kinesis",
        "aws-cpp-sdk-lambda",
        "aws-cpp-sdk-dynamodb",
        "aws-crt-cpp",
        "aws-c-s3",
    };

    public AWSSDK(ReadOnlyTargetRules Target) : base(Target)
    {
        // ModuleType.External tells the engine not to look for (or compile) any source code.
        Type = ModuleType.External;
        PCHUsage = ModuleRules.PCHUsageMode.UseExplicitOrSharedPCHs;

        // add the header files for reference
        PublicIncludePaths.Add(Path.Combine(ModuleDirectory, "Include"));

        // AWS SDK relies on certain identifiers being undefined, so this produces warnings
        // Unreal engine treats certain warnings as errors and fails the build
        // this line will disable those warnings:
        bEnableUndefinedIdentifierWarnings = false;

        // Dynamically linking to the SDK requires us to define the
        // USE_IMPORT_EXPORT symbol for all build targets using the
        // SDK. Source: https://github.com/aws/aws-sdk-cpp/blob/main/Docs/SDK_usage_guide.md#build-defines
        PublicDefinitions.Add("USE_IMPORT_EXPORT");
        PublicDefinitions.Add("AWS_CRT_CPP_USE_IMPORT_EXPORT");


        if (Target.Platform == UnrealTargetPlatform.Win64)
        {
            PublicDefinitions.Add("USE_WINDOWS_DLL_SEMANTICS");
        }

        // do this for each lib and dll
        string LibraryPath = Path.Combine(ModuleDirectory, "Binaries", Target.Platform.ToString());
        bool bHasAWSSDK = Directory.Exists(LibraryPath);
        if (bHasAWSSDK)
        {
            PublicDefinitions.Add("WITH_AWSSDK=1");
            foreach (string libName in LibraryNames)
            {
                // add a new section for each platform you plan to compile for (only Win64 is included for this example)
                if (Target.Platform == UnrealTargetPlatform.Win64)
                {
                    PublicAdditionalLibraries.Add(Path.Combine(LibraryPath, libName + ".lib"));
                    // Stage the library along with the target, so it can be loaded at runtime.
                    RuntimeDependencies.Add("$(BinaryOutputDir)/" + libName + ".dll", Path.Combine(LibraryPath, libName + ".dll"));
                }
                else if (Target.Platform == UnrealTargetPlatform.Mac)
                {
                    // add mac libraries
                }
            }
            if (Target.Platform == UnrealTargetPlatform.Linux)
            {
                foreach (string libName in LinuxLibraryNames)
                {
                    // add linux libraries
                    string SDKLib = (Path.Combine(LibraryPath, libName));
                    PublicAdditionalLibraries.Add(SDKLib);
                    RuntimeDependencies.Add("$(BinaryOutputDir)/"+libName, Path.Combine(SDKLib));
                }
            }
        }
        else
        {
            PublicDefinitions.Add("WITH_AWSSDK=0");
        }

        PrivateDependencyModuleNames.AddRange(
        new string[] {
                    "CoreUObject",
                    "Engine",
                    "Slate",
                    "SlateCore",
        });
    }
}

I am trying to invoke lambda function with the following code:

void UAWSLibrary::InvokeLambdaFunction(FString functionName)
{
	Aws::Lambda::Model::InvokeRequest invokeRequest;
	const char* funcName = TCHAR_TO_ANSI(*functionName);
	invokeRequest.SetFunctionName(funcName);
	invokeRequest.SetInvocationType(Aws::Lambda::Model::InvocationType::RequestResponse);
	invokeRequest.SetLogType(Aws::Lambda::Model::LogType::Tail);
	std::shared_ptr<Aws::IOStream> payload = Aws::MakeShared <Aws::StringStream>("FunctionTest");
	Aws::String TestString = "Hello World";
	Aws::Utils::Json::JsonValue jsonPayload;
	Aws::String payloadString;
	jsonPayload.AsString(payloadString);
	jsonPayload.WithString(TestString, TestString);
	*payload << jsonPayload.View().WriteReadable();
	invokeRequest.SetBody(payload);
	invokeRequest.SetContentType("application/javascript");
	auto outcome = m_client->Invoke(invokeRequest);
	if (outcome.IsSuccess())
	{
		auto& result = outcome.GetResult();
		Aws::IOStream& payloadResponse = result.GetPayload();
		Aws::String functionResult;
		std::getline(payloadResponse, functionResult);
		GEngine->AddOnScreenDebugMessage(-1,5.0f, FColor::Green, functionResult.c_str());
	}
}

Any help would be appreciated.

[MichaelChidiac]

Hello GabrieliusD,

I don't have an answer to your question but I noticed you mentioned managing to implement the plugin in Windows. I've been trying to do the same but I'm getting entry point errors when after compiling the library.

Would you mind sharing with me the process with which you pulled the source code and built it?

Thanks a lot for the help.

[GabrieliusD]

Hello Michael,

I used this blog to implement the plugin in windows: https://aws.amazon.com/blogs/gametech/how-to-integrate-the-aws-c-sdk-with-unreal-engine/

[jmklix]

Thanks for bringing this issue up. We don't currently support unreal engine, but it is something that we would like to add support for. I have created a feature request for this. Marking this as answered for now, but please let us know if you run into any problems after support has been added.

[github-actions[bot]]

Hello! Reopening this discussion to make it searchable.