I am experiencing an interesting issue where the HttpClient being used hangs, and then it makes the activity function to time out(as it can run up to 10 minutes). It usually hangs after 200 - 500 payloads have been processed.

Has anyone else experienced a similar issue?

The code is being used the same way as it's illustrated at the following example:

public class ActivityFunction(InjectedService injectedService)
{
    
    [Function(nameof(ActivityFunction))]
    public async Task  Run([ActivityTrigger] ActivityFunctionRequest request)
    {
        string jwt = "...";

        var payloads = new List<Payload>();

        foreach (var payload in payloads)
        {
            using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(20));
            
            await injectedService.Action(payload, jwt, cts.Token);
        }
    }
}


public class InjectedService(IHttpClientFactory httpClientFactory)
{
    public async Task Action(Payload payload, string jwtToken, CancellationToken cancellationToken)
    {
        var client = httpClientFactory.CreateClient();
        client.BaseAddress = new Uri(";);
        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", jwtToken);

        await client.PostAsJsonAsync("api/abc/action", payload, cancellationToken);
    }
}

I tried to use a named HttpClient, the Timeout property on HttpClient, but nothing seemed to help.

I am experiencing an interesting issue where the HttpClient being used hangs, and then it makes the activity function to time out(as it can run up to 10 minutes). It usually hangs after 200 - 500 payloads have been processed.

Has anyone else experienced a similar issue?

The code is being used the same way as it's illustrated at the following example:

public class ActivityFunction(InjectedService injectedService)
{
    
    [Function(nameof(ActivityFunction))]
    public async Task  Run([ActivityTrigger] ActivityFunctionRequest request)
    {
        string jwt = "...";

        var payloads = new List<Payload>();

        foreach (var payload in payloads)
        {
            using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(20));
            
            await injectedService.Action(payload, jwt, cts.Token);
        }
    }
}


public class InjectedService(IHttpClientFactory httpClientFactory)
{
    public async Task Action(Payload payload, string jwtToken, CancellationToken cancellationToken)
    {
        var client = httpClientFactory.CreateClient();
        client.BaseAddress = new Uri("http://api.test");
        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", jwtToken);

        await client.PostAsJsonAsync("api/abc/action", payload, cancellationToken);
    }
}

I tried to use a named HttpClient, the Timeout property on HttpClient, but nothing seemed to help.

• c#
• azure
• azure-functions
• httpclient

• Maybe your api api.test is not capable of recieving so much requests. Did you consider using a ratelimiter? If the recieving api is also hosted in azure you could use message queues to enable easy and lightweight communication. – Sebastian Siemens Commented 2 days ago
• 1 Could you please also share your Orchestrator Function? It's possible something in there is contributing to the problem. – Andrew B Commented 2 days ago

1 Answer 1

You should be using message queues for this since you have the potential for timeout issues, as you've found out.

The Run function would just loop through the List<Payloads> adding a new message to the queue containing the item from the list.

The Action function would be subscribed to the queue and handle each payload. It could also put the message back on the queue should there be a problem with the API it is calling so it can be retried.