Azure Cosmos DB + Functions Cookbook - monitoring

Function.cs

[FunctionName("Monitor")]
public static async Task Monitor(
    [TimerTrigger("*/1 * * * * *", RunOnStartup = true)] TimerInfo timer, // Timer will trigger every 1 second, adjust CRON expression
    [CosmosDB("%MonitoredDatabase%", "%MonitoredCollection%", ConnectionStringSetting = "CosmosDB")] DocumentClient monitoredCollectionClient, 
    [CosmosDB("%MonitoredDatabase%", "leases", ConnectionStringSetting = "CosmosDB")] DocumentClient leaseCollectionClient,
    ILogger log)
{
    var estimator = GetRemainingWorkEstimator(monitoredCollectionClient, leaseCollectionClient);
    var remainingWork = await estimator.GetEstimatedRemainingWork();
    // Send custom metric to App Insight
    log.LogInformation(remainingWork.ToString());
    log.LogMetric("RemainingWork", remainingWork);
}