Know Your Cloud Resource Costs on Azure

GetResourceGroupOwnersAsync.cs

public async Task<IEnumerable<ResourceGroupOwner>> GetResourceGroupOwnersAsync(DateTime dateStart, DateTime dateEnd, bool runEntirePeriod, decimal threshold)
{
    var costs = await this._dbContext.ResourceGroupCostHistories
                          .ToListAsync().ConfigureAwait(false);

    ...

    var owners = costs.GroupBy(
                               p => new
                                        {
                                            Subscription = p.Subscription,
                                            ResourceGroupName = p.ResourceGroupName,
                                            Owners = p.Owners
                                        })
                      .Select(
                              p => new ResourceGroupOwner()
                                       {
                                           Subscription = p.Key.Subscription,
                                           SubscriptionId = p.OrderByDescending(q => q.DateStart).First().SubscriptionId,
                                           ResourceGroupName = p.Key.ResourceGroupName,
                                           Owners = p.Key.Owners,
                                           Cost = p.Sum(q => q.Cost),
                                           TotalSpendLimit = p.OrderByDescending(q => q.DateStart).First().TotalSpendLimit,
                                           DailySpendLimit = p.OrderByDescending(q => q.DateStart).First().DailySpendLimit,
                                           OverspendAction = p.OrderByDescending(q => q.DateStart).First().OverspendAction
                                       })
                      .Where(p => p.Owners != null);

    // Total spend limit
    if (runEntirePeriod)
    {
        owners = owners.Where(p => p.TotalSpendLimit > 0.00M);

        // Threshold
        owners = threshold < 1.00M
                     ? owners.Where(p => p.TotalSpendLimit * threshold <= p.Cost && p.Cost < p.TotalSpendLimit)
                     : owners.Where(p => p.Cost >= p.TotalSpendLimit * threshold);
    }
    else
    {
        // Daily spend limit
        owners = owners
                       .Where(p => p.DailySpendLimit > 0.00M)
                       .Where(p => p.Cost > p.DailySpendLimit);
    }

    owners = owners.OrderBy(p => p.Owners)
                   .ThenBy(p => p.ResourceGroupName)
                   .ToList();

    return owners;
}