Windows 服务上传到 AWS S3

Question

I am attempting to create a windows service that periodically checks a folder and uploads any new files that were created into an S3 bucket.

It seems that the code is not finding my app.config file and thus not locating the AWSProfileName or any other values.

 private bool Upload(List<string> files,string bucketname, RegionEndpoint bucketRegion)
    {
        IAmazonS3 S3Client = new AmazonS3Client(bucketRegion);
        TransferUtility tranUtil = new TransferUtility(S3Client);
        foreach (string file in files)
        {
            tranUtil.Upload(file, bucketname, file.Replace(configFolderPath, ""));
        }
        return true;
    }

Throws me this exception

System.NullReferenceException: 'Object reference not set to an instance of an object.'

here's my app config too (with values removed)

 <?xml version="1.0" encoding="utf-8"?>
<configuration>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.1" />
  </startup>
  <appSettings>
    <!--AWSProfileName is used to reference an account that has been registered with the SDK.
If using AWS Toolkit for Visual Studio then this value is the same value shown in the AWS Explorer.
It is also possible to register an account using the <solution-dir>/packages/AWSSDK-X.X.X.X/tools/account-management.ps1 PowerShell script
that is bundled with the nuget package under the tools folder.
-->
    <add key="AWSProfileName" value="******" />
    <add key="profile" value="******" />
    <add key="region" value="******" />
    <add key="configuration" value="******" />
    <add key="framework" value="netcoreapp2.1" />
  </appSettings>
</configuration>

I can run the exact same code & app.config in a console app and it will upload the files without any trouble.

I have also tried to break out the credentials:

private bool Upload(List<string> files,string bucketname, RegionEndpoint bucketRegion)
        {
            AWSCredentials creds = new StoredProfileAWSCredentials("My AWS Profile Name");
            IAmazonS3 S3Client = new AmazonS3Client(creds, bucketRegion);
            TransferUtility tranUtil = new TransferUtility(S3Client);...

only to get this exception:

System.ArgumentException: 'App.config does not contain credentials information. Either add the AWSAccessKey and AWSSecretKey properties or the AWSProfileName property.'

But I DO have the AWSProfileName in the config...

What's going on with the Windows service that breaks this?

Workaround Found

I was following this example

After properly setting up a user's IAM policies you can manually set the access key and secret yourself using an overload of the S3 client constructor. Obviously would want to load that from a file outside of the project.

        IAmazonS3 S3Client = new AmazonS3Client("IAM USER ACCESS KEY ID", "IAM USER ACCESS KEY SECRET", bucketRegion);

Answer 1

When you build a Windows Service in release mode your app.config file is converted by Visual Studio into a file called yourprogram.exe.config. Check that this config file contains the connection information. This file must be in the same location as the exe.

Your config is specifying a profile contained in the SDK Store. SDK Store profiles are specific to a particular user within a particular host.

When you run the app in a console, you are running it under your user account. The app will be able to look in your SDK Store and find the profile and the associated credentials.

When you run the app as a service it will be using a different user account; it will therefore not be able to find the profile in the SDK Store and so will not be able to connect.

You could create a credentials file and link that eg:

    <configuration>
      <appSettings>
        <add key="AWSProfileName" value="xxxxxx"/>
        <add key="AWSProfilesLocation" value="C:\aws_service_credentials\credentials"/>
      </appSettings>
    </configuration>

You use a text editor to manage the profiles in a credentials file. The file should be named credentials and stored in the location you specify in AWSProfilesLocation

Each profile has the following format:

[{profile_name}]
aws_access_key_id = {accessKey}
aws_secret_access_key = {secretKey}

More Information:
https://docs.aws.amazon.com/sdk-for-net/v2/developer-guide/net-dg-config-creds.html