创建具有不同配置的相同依赖项的多个实例

Question

I have an application ( IJobInit ) that uses a list from JSON settings to create multiple instances of a class ( IJob ). This class does some work using two other dependencies, IInputClient and IOutputClient . It uses M.Extensions.DependencyInjection to create a container which is handed off to AutoFac to create an IContainer.

IJobInit(IContainer container)

I would like IInputClient to be configured different for each instance of IJob. Speficially, I'd like to pass in a secret for it to use. The result would be:

IInputClient(HttpClient client)

where HttpClient is configured using ConfigureHttpClient such that IJob does not know that it is pre-authenticated. This would also be suitable:

IInputClient(ISecretProvider secretsProvider, string secretName)

The end result is three instances of IJob with IInputClient configured differently.

IJob(IInputClient inputClient1, IOutputClient outputClient)
IJob(IInputClient inputClient2, IOutputClient outputClient)
IJob(IInputClient inputClient3, IOutputClient outputClient)

How do I achieve this? I was looking at Autofac scopes but those controlwhen an instance is created without any control over its configuration (unless I missed it).

A colleague suggested that I could host each instance of IJob in its own process with its own configuration which is possible but I'm trying to host all the jobs in a single Azure Function and use the list in config to create the inner jobs.

Thanks!

Answer 1

I'm not totally happy with this solution but it works for now.

        private async Task<IInputClient> GetClientAsync(string secretId)
        {
            HttpClient httpClient = this.httpClientFactory.CreateClient();

            string secret = await this.secretsProvider.GetSecretAsync(secretId);
            httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(Encoding.ASCII.GetBytes(string.Concat(":", secret))));

            return this.scope.Resolve<IInputClient>(new TypedParameter(typeof(HttpClient), httpClient));
        }