BackgroundWorker

Background Worker Example

Demonstrates using Replane in a long-running background service with real-time config updates.

Prerequisites

• .NET 8.0 SDK or later
• A running Replane server
• An SDK key from your Replane project

Setup

1. Copy this directory to your local machine:

   cp -r BackgroundWorker ~/my-replane-example
   cd ~/my-replane-example

2. Set your environment variables:

   export REPLANE_BASE_URL="https://your-replane-server.com"
   export REPLANE_SDK_KEY="your-sdk-key"

3. Restore packages:

   dotnet restore

Running

dotnet run

Press Ctrl+C to stop the worker.

What This Example Demonstrates

Subscriptions

Subscribe to config changes and react in real-time:

// Subscribe to ALL config changes
var unsubscribe = client.Subscribe((configName, config) =>
{
    Console.WriteLine($"Config changed: {configName} = {config.Value}");
});

// Subscribe to a SPECIFIC config
var unsubscribe = client.SubscribeConfig("batch-size", config =>
{
    Console.WriteLine($"Batch size is now: {config.Value}");
});

Unsubscribing

Both Subscribe() and SubscribeConfig() return an unsubscribe function:

var unsubscribe = client.Subscribe(...);

// Later, when you want to stop receiving updates:
unsubscribe();

Real-Time Updates

The Replane client maintains a persistent SSE connection:

• Config changes are pushed from the server instantly
• No polling required
• Subscriptions fire immediately when configs change

Dynamic Configuration

This example shows how to dynamically adjust worker behavior:

• worker-enabled: Toggle the worker on/off
• batch-size: Change processing batch size
• interval-seconds: Adjust the polling interval

Sample Output

=== Replane Background Worker Example ===
This example demonstrates real-time config updates.

Connecting to Replane...
Connected! Subscribed to config changes.

Starting background worker...
Press Ctrl+C to stop.

[14:30:00] Processing batch #1 (size: 100)
[14:30:00] Batch #1 completed
[14:30:00] Waiting 30 seconds...

[14:30:15] Config changed: batch-size = 200
[14:30:15] Batch size updated to: 200
  -> Worker will adjust batch processing...

[14:30:30] Processing batch #2 (size: 200)
[14:30:30] Batch #2 completed
[14:30:30] Waiting 30 seconds...

Use Cases

• Background job processors: Adjust batch sizes, intervals dynamically
• Queue consumers: Enable/disable consumption without restart
• Scheduled tasks: Change cron expressions at runtime
• Feature flags: Enable new features for background processes
• Rate limiting: Dynamically adjust rate limits

Best Practices

1. Always unsubscribe when shutting down to prevent memory leaks
2. Handle exceptions in subscription callbacks
3. Don't block the subscription callback - offload heavy work
4. Use specific subscriptions when you only care about one config