CODEWITHSUNDEEP
c#multithreadingtask-parallel-librarybatch-processing
Stephen Gray
Stephen Gray

Reputation: 75

Execution Queue

I have a need to process 100 pieces of information through an external program. These processes can be intensive, so I need to limit it to processing 8 at a time. Essentially, I'd like to launch 8 processes, and as each one completes, launch the next one.

I have attempted to use TPL in System.Threading.Tasks.Dataflow with the below code, but all 100 launch, not just 8 at a time.

// This file has the command line parameters to launch the external process
List<string> lines = File.ReadAllLines(file).ToList();
var block = new ActionBlock<string>(async job => await RunJob(job), new ExecutionDataflowBlockOptions { MaxDegreeOfParallelism = 1 });
foreach (string line in lines)
        {
            block.SendAsync(line);

        }

static async Task RunJob(string parms)
        {
            //Console.WriteLine("PARMS: {0}", parms);
            Process proc = new Process();
            ProcessStartInfo start = new ProcessStartInfo();
            start.WindowStyle = ProcessWindowStyle.Normal;
            start.FileName = @"C:\program.exe";
            string parameters = String.Format(parms.ToString());
            start.Arguments = parameters;
            start.UseShellExecute = true;
            proc.StartInfo = start;
            proc.Start();
        }

What have I missed? Thanks for the help.

Upvotes: 3

Views: 200

Answers (1)

Access Denied
Access Denied

Reputation: 9501

Process starts immediately, but you don't wait until process ends. Use proc.WaitForExit();

static async Task RunJob(string parms)
{
    //Console.WriteLine("PARMS: {0}", parms);
    Process proc = new Process();
    ProcessStartInfo start = new ProcessStartInfo();
    start.WindowStyle = ProcessWindowStyle.Normal;
    start.FileName = @"C:\program.exe";
    string parameters = String.Format(parms.ToString());
    start.Arguments = parameters;
    start.UseShellExecute = true;
    proc.StartInfo = start;
    proc.Start();
    proc.WaitForExit();
}

Upvotes: 2

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