Mostlylucid.Ephemeral.Patterns.DynamicConcurrency 2.3.2

Mostlylucid.Ephemeral.Patterns.DynamicConcurrency

Dynamic concurrency adjustment based on load signals.

dotnet add package mostlylucid.ephemeral.patterns.dynamicconcurrency

Quick Start

using Mostlylucid.Ephemeral.Patterns.DynamicConcurrency;

var sink = new SignalSink();

await using var demo = new DynamicConcurrencyDemo<WorkItem>(
    async (item, ct) => await ProcessAsync(item, ct),
    sink,
    minConcurrency: 2,
    maxConcurrency: 64);

// External system raises load signals
sink.Raise("load.high");  // Doubles concurrency
sink.Raise("load.low");   // Halves concurrency

All Options

new DynamicConcurrencyDemo<T>(
    // Required: async work body
    body: async (item, ct) => await ProcessAsync(item, ct),

    // Required: shared signal sink
    sink: signalSink,

    // Minimum concurrency level
    // Default: 1
    minConcurrency: 1,

    // Maximum concurrency level
    // Default: 32
    maxConcurrency: 32,

    // Signal pattern to trigger scale up
    // Default: "load.high"
    scaleUpPattern: "load.high",

    // Signal pattern to trigger scale down
    // Default: "load.low"
    scaleDownPattern: "load.low"
)

API Reference

// Enqueue work item
await demo.EnqueueAsync(item, ct);

// Check current concurrency level
int current = demo.CurrentMaxConcurrency;

// Drain and dispose
await demo.DrainAsync(ct);
await demo.DisposeAsync();

How It Works

A background loop monitors signals and adjusts concurrency:

Signal "load.high" detected:
    Current: 4 -> Next: min(8, max) = 8  (doubled)

Signal "load.low" detected:
    Current: 8 -> Next: max(4, min) = 4  (halved)

Check interval: 200ms

Example: Auto-Scaling Worker

var sink = new SignalSink();

await using var worker = new DynamicConcurrencyDemo<Job>(
    async (job, ct) => await ProcessJob(job, ct),
    sink,
    minConcurrency: 2,
    maxConcurrency: 64);

// Monitor system metrics and raise signals
Task.Run(async () =>
{
    while (true)
    {
        var metrics = await GetSystemMetrics();

        if (metrics.CpuUsage < 30 && metrics.QueueDepth > 1000)
            sink.Raise("load.high");  // Scale up
        else if (metrics.CpuUsage > 80 || metrics.QueueDepth < 10)
            sink.Raise("load.low");   // Scale down

        await Task.Delay(1000);
    }
});

foreach (var job in jobs)
    await worker.EnqueueAsync(job);

Example: Custom Signal Patterns

await using var worker = new DynamicConcurrencyDemo<Task>(
    ProcessTaskAsync,
    sink,
    scaleUpPattern: "scale.up.*",    // Match scale.up.cpu, scale.up.queue, etc.
    scaleDownPattern: "scale.down.*");

sink.Raise("scale.up.queue");    // Triggers scale up
sink.Raise("scale.down.memory"); // Triggers scale down

Related Packages

License

Unlicense (public domain)