Rancher in ASP.NET Core

RancherClient.cs

public void ConfigureServices(IServiceCollection services)
{
    services.AddHttpClient<IRancherClient, RancherClient>();
}

public interface IRancherClient
{
    Task<HttpResponseMessage> ProjectStackActionAsync(string project, string stack, string action,
        HttpContent content = null);

    Task<HttpResponseMessage> ProjectServiceActionAsync(string project, string service, string action,
        HttpContent content = null);
}

public sealed class RancherClient : IRancherClient
{
    private readonly StringContent _emptyContent = new ImmutableStringContent("{}");
    private readonly HttpClient _httpClient;

    public RancherClient(HttpClient httpClient) => _httpClient = Configure(httpClient);

    public async Task<HttpResponseMessage> ProjectStackActionAsync(string project, string stack, string action,
        HttpContent content = null)
    {
        using (var httpRequestMessage = new HttpRequestMessage(
            HttpMethod.Post,
            $"/v2-beta/projects/{project}/stacks/{stack}/?action={action}")
        {
            Content = content ?? _emptyContent
        })
        {
            return await _httpClient.SendAsync(httpRequestMessage).ConfigureAwait(false);
        }
    }

    public async Task<HttpResponseMessage> ProjectServiceActionAsync(string project, string service, string action,
        HttpContent content = null)
    {
        using (var httpRequestMessage = new HttpRequestMessage(
            HttpMethod.Post,
            $"/v2-beta/projects/{project}/services/{service}/?action={action}")
        {
            Content = content ?? _emptyContent
        })
        {
            return await _httpClient.SendAsync(httpRequestMessage).ConfigureAwait(false);
        }
    }

    private static HttpClient Configure(HttpClient httpClient)
    {
        var url = Environment.GetEnvironmentVariable("CATTLE_URL");
        if (null == url)
            return httpClient;

        var uriBuilder = new UriBuilder(url) {Path = null};
        httpClient.BaseAddress = uriBuilder.Uri;

        var authString = Environment.GetEnvironmentVariable("CATTLE_AGENT_INSTANCE_AUTH");
        if (null == authString)
            return httpClient;

        httpClient.DefaultRequestHeaders.Authorization = AuthenticationHeaderValue.Parse(authString);
        return httpClient;
    }
}

/// <inheritdoc />
/// <summary>
///     StringContent that can be re-used.
/// </summary>
/// <remarks>Use for constants</remarks>
public sealed class ImmutableStringContent : StringContent
{
    public ImmutableStringContent(string content) : base(content)
    {
    }

    public ImmutableStringContent(string content, Encoding encoding) : base(content, encoding)
    {
    }

    public ImmutableStringContent(string content, Encoding encoding, string mediaType) : base(
        content,
        encoding,
        mediaType)
    {
    }

    protected override void Dispose(bool disposing)
    {
        // don't do anything
    }
}

Usage:

var project = "1a50305";
var service = "1s10124";
var action = "deactivate";
var response = await _rancherClient.ProjectServiceActionAsync(project, service, action);

If you create a service that needs to interact with the Rancher API, service account API keys will need to be created for the containers so that the service will be able to access the API for authenticated set ups

https://rancher.com/docs/rancher/v1.6/en/rancher-services/service-accounts/