Verify max value for maxPollingInterval

[hossam-nasr]

Library name

Microsoft.Azure.WebJobs.Extensions.Storage

Please describe the feature.

This issue was inspired by this CRI. Track 1 version: Azure/azure-webjobs-sdk#2967.

In the storage queue extension trigger, the extension polls the queue in extension to check for new messages. If it fails, it waits a certain amount of time, the polling interval, between polling the queue again. The polling algorithm is described in the docs here. The polling interval increases exponentially in the case of failure, up to a maximum value of the maxPollingInterval set by the user (default is 1 minute). However, if the user misconfigures the maxPollingInterval property (as was the case in the CRI), it can result in very long polling intervals, leading to periods of downtime in the app. We have a safeguard to check against a minimum value of maxPollingInterval, but we should add a check for an upper on that value as well, to at least warn the user about the potential problems.

This is also exacerbated by how maxPollingInterval relies on the TimeSpan.Parse() function:

TimeSpan ts = TimeSpan.Parse("10000");
Console.WriteLine(ts);
Console.WriteLine($"TotalDays: {ts.TotalDays}");

Output:

10000.00:00:00
TotalDays: 10000

Which makes it easy to accidentally configure an almost infinitely long maxPollingInterval