Sync Services

Sync Services synchronize data between your database layer and cache layer, offering a seamless way to move data between them.

What Is a Sync Service?

A Sync Service implements ISyncService and defines two key operations:

• PullAsync() — loads data from a remote source (e.g., database) into the local in-memory cache
• PushAsync() — pushes data from the cache to a remote target (e.g., database)

Example

[Service(typeof(ISyncService))]
public class LeaderboardSyncService : AbstractVaultCacheSyncService<LeaderboardModel>
{
    public LeaderboardSyncService(ICacheProvider cache, IVault<LeaderboardModel>? vault = null)
        : base(cache, vault) { }

    public override async Task PullAsync()
    {
        ValidateVault();
        var top100 = await _vault
            .OrderByDescending(x => x.Score)
            .Take(100)
            .ToListAsync();

        foreach (var entry in top100)
        {
            await SaveAsync(entry);
        }
    }
}

The [Service(typeof(ISyncService))] attribute registers the service — Altruist auto-discovers it and calls PullAsync at startup.

Behavior

• Altruist automatically calls PullAsync at startup to preload cache from the database
• Runtime syncs must be triggered manually
• If no database is configured, sync services gracefully fall back to cache-only operations

Best Practices

• Keep PullAsync() logic lightweight
• Only override PullAsync() if you need filtered or partial data
• Use PushAsync() for periodic flushing of cache to database