> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tensor9.com/llms.txt
> Use this file to discover all available pages before exploring further.

# AWS .NET SDK Guide

> Configure the AWS SDK for .NET to use a Cloud Adapter endpoint and inspect service failures.

This example uses `AWSSDK.S3`. Your code keeps using `IAmazonS3`; the client configuration directs requests to Cloud Adapter.

## Start a local adapter

This guide's bounded example uses S3 backed by Google Cloud Storage:

**1. Install or update the Tensor9 CLI**

Install the customer CLI with Homebrew, then confirm the binary is available:

```bash theme={null}
brew tap tensor9ine/tensor9
brew trust tensor9ine/tensor9
brew install tensor9
tensor9 --version
```

If `tensor9` is already installed, run `brew upgrade tensor9` instead of the install command.

**2. Authenticate with Tensor9**

To create a Tensor9 account and download an API key yourself, follow [Get a Tensor9 API key](https://docs.tensor9.com/byoc/getting-started/api-key.md).

A Tensor9 API key is required. Use the key issued during onboarding, or email [hello@tensor9.com](mailto:hello@tensor9.com) to request one for your organization. Do not share your account or key with another customer or organization.

If your secret manager has already supplied `T9_API_KEY`, skip the prompt. Otherwise, enter your key at a hidden prompt in the terminal where you will run `tensor9`:

> [tab] Bash
>
> ```bash theme={null}
> set +x
> IFS= read -r -s -p 'Tensor9 API key: ' T9_API_KEY
> printf '\n'
> export T9_API_KEY
> ```

> [tab] Zsh
>
> ```zsh theme={null}
> set +x
> IFS= read -r -s 'T9_API_KEY?Tensor9 API key: '
> printf '\n'
> export T9_API_KEY
> ```

Check that the variable is set without printing it, then verify your Tensor9 identity:

```bash theme={null}
: "${T9_API_KEY:?Set T9_API_KEY before continuing}"
tensor9 whoami
```

Confirm that the reported identity belongs to the intended customer account. Do not continue if authentication fails or the account is wrong. While `T9_API_KEY` is set, `tensor9` commands in this terminal use the key instead of any controller profile, so use a separate terminal for this work and run `unset T9_API_KEY` when you finish. Keep shell tracing disabled while using the key. Do not paste the key into commands, shell profiles, source files, screenshots or support messages.

See [Install and Authenticate](https://docs.tensor9.com/cloud-adapter-early-access/getting-started/install-and-authenticate.md) for the planned license lifecycle, entitlements and credential boundaries.

**3. Inspect the S3 to Google Cloud Storage mapping**

Ask Tensor9 to describe the exact directed service mapping used by this guide:

```bash theme={null}
tensor9 explain \
  -origin aws::1.0.0::s3 \
  -target google::1.0.0::gcs \
  -fmt Human
```

Read the supported S3 operations and Google Cloud Storage limitations before starting the process. The mapping is directional: this command describes S3 requests adapted to Google Cloud Storage, not the reverse direction.

**4. Prepare Google Cloud access**

Authenticate with Google Cloud using its standard Application Default Credentials chain. The adapter uses that identity when it calls Google Cloud Storage.

Use a dedicated test project and narrowly scoped credentials. Do not put credentials in the command line, source code, or screenshots.

**5. Start the S3 service adapter**

Run the S3 to Google Cloud Storage adapter as a foreground process:

```bash theme={null}
tensor9 adapt svc run \
  --origin aws::1.0.0::s3 \
  --backend google::1.0.0::gcs
```

Leave this terminal open. This is the current foreground launcher, not the pending Docker launcher for [local development mode](https://docs.tensor9.com/cloud-adapter-early-access/deployment/single-binary.md). It calls your actual target-cloud services; it is separate from the in-memory emulator. Acquisition and license renewal require Tensor9 authentication. Keep the endpoint local to your test.

**6. Copy the listening endpoint**

When the command reports its listening endpoint, copy that exact value into a second terminal:

```bash theme={null}
export T9_CLOUD_ADAPTER_ENDPOINT="<endpoint printed by tensor9>"
```

Keep the endpoint local to the test unless you have deliberately configured network access and authentication for another machine.

**7. Run one bounded S3 request**

Continue with this page's client or tool instructions. Point only S3 at `T9_CLOUD_ADAPTER_ENDPOINT`, then perform one operation whose Google Cloud Storage effect you can verify independently.

Check both sides: read the S3-shaped response and inspect the native object or bucket in Google Cloud Storage. A successful client response alone does not prove that the target state is correct.

**8. Stop the local adapter**

Return to the first terminal and press **Control-C**. Confirm the process exits before deleting the test object or bucket with Google Cloud's native client.

If the request failed, preserve the request ID, adapter endpoint, S3 operation name, Google Cloud request ID, and any `x-t9-explain-*` receipt headers before stopping the process.

## Choose how to set the endpoint

### Set it for the process

```bash theme={null}
export AWS_ENDPOINT_URL_S3="$T9_CLOUD_ADAPTER_ENDPOINT"
```

AWS SDK for .NET reads the service-specific setting when `ServiceURL` is not assigned:

```csharp theme={null}
using System;
using Amazon.Runtime;
using Amazon.S3;

var credentials = new StoredProfileAWSCredentials("adapter-test");
var config = new AmazonS3Config
{
    AuthenticationRegion = "us-east-1",
    ForcePathStyle = true,
    Timeout = TimeSpan.FromSeconds(30),
    MaxErrorRetry = 2,
};
IAmazonS3 s3 = new AmazonS3Client(credentials, config);
```

### Set it on one client

```bash theme={null}
: "${T9_CLOUD_ADAPTER_ENDPOINT:?start the local adapter and copy its endpoint first}"
```

```csharp theme={null}
using System;
using Amazon;
using Amazon.Runtime;
using Amazon.S3;

var credentials = new StoredProfileAWSCredentials("adapter-test");
var config = new AmazonS3Config
{
    ServiceURL = Environment.GetEnvironmentVariable("T9_CLOUD_ADAPTER_ENDPOINT"),
    AuthenticationRegion = "us-east-1",
    ForcePathStyle = true,
    Timeout = TimeSpan.FromSeconds(30),
    MaxErrorRetry = 2,
};

IAmazonS3 s3 = new AmazonS3Client(credentials, config);
```

`ServiceURL` selects the adapter endpoint. `AuthenticationRegion` keeps AWS signing behavior explicit. The adapter's target-cloud identity remains in service adapter configuration, not in the .NET process.

An explicit `ServiceURL` takes precedence over `AWS_ENDPOINT_URL_S3`.

## Verify a lifecycle

```csharp theme={null}
using System;
using System.IO;
using Amazon.S3.Model;
using System.Text;

var bucket = Environment.GetEnvironmentVariable("TEST_BUCKET")!;
var key = $"dotnet/{DateTimeOffset.UtcNow.ToUnixTimeMilliseconds()}-hello.txt";
var expected = "hello through Cloud Adapter\n";

var put = await s3.PutObjectAsync(new PutObjectRequest
{
    BucketName = bucket,
    Key = key,
    ContentBody = expected,
    ContentType = "text/plain",
});

var head = await s3.GetObjectMetadataAsync(bucket, key);
using var get = await s3.GetObjectAsync(bucket, key);
using var reader = new StreamReader(get.ResponseStream, Encoding.UTF8);
var actual = await reader.ReadToEndAsync();
if (actual != expected) throw new InvalidOperationException("Downloaded bytes differ");

await s3.DeleteObjectAsync(bucket, key);
```

Inspect the native target object after the put. Record `put.ResponseMetadata.RequestId`, `put.HttpStatusCode`, the target object name, and the adapter version with your test evidence.

## Handle errors

```csharp theme={null}
try
{
    await s3.GetObjectMetadataAsync(bucket, "missing-key");
}
catch (AmazonS3Exception error)
{
    Console.Error.WriteLine(new
    {
        error.ErrorCode,
        error.StatusCode,
        error.RequestId,
        error.Message,
    });
}
catch (AmazonServiceException error)
{
    Console.Error.WriteLine($"Service failure: {error.Message}");
}
```

Network and cancellation failures may have no service response. Do not treat missing response metadata as a translated AWS error. After a timeout on a mutation, inspect target state before retrying.

## Production checklist

* Reuse `IAmazonS3`; do not construct a client per request.
* Pass cancellation tokens from the application boundary.
* Test the exact retry, paginator, multipart, and conditional behaviors you use.
* Keep origin credentials and backend credentials separate.
* Do not log signed headers, request bodies, or secret values.
* Compare operations with [S3 target coverage](https://docs.tensor9.com/cloud-adapter-early-access/service-catalog/aws/databases-storage/s3.md).

Use [Debugging Your Adapters](https://docs.tensor9.com/cloud-adapter-early-access/debugging/overview.md) when the SDK response and native target state disagree.


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