SEBWIN-301, SEBWIN-322: Improved service feature configuration with retry mechanism.

This commit is contained in:
dbuechel 2019-08-28 09:54:52 +02:00
parent 18e6b366a5
commit d54d7c17dc

View file

@ -18,7 +18,9 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.ServiceConfigurations
[Serializable]
internal abstract class ServiceConfiguration : FeatureConfiguration
{
private static readonly TimeSpan TEN_SECONDS = TimeSpan.FromSeconds(10);
private static readonly TimeSpan FIVE_SECONDS = TimeSpan.FromSeconds(5);
private const int MAX_ATTEMPTS = 5;
private IList<ServiceDataItem> originalItems;
protected abstract IEnumerable<ServiceConfigurationItem> Items { get; }
@ -34,7 +36,7 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.ServiceConfigurations
foreach (var item in Items)
{
success &= TrySet(new ServiceDataItem { Name = item.Name, Status = item.Disabled });
success &= TrySetWithRetry(new ServiceDataItem { Name = item.Name, Status = item.Disabled });
}
if (success)
@ -55,7 +57,7 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.ServiceConfigurations
foreach (var item in Items)
{
success &= TrySet(new ServiceDataItem { Name = item.Name, Status = item.Enabled });
success &= TrySetWithRetry(new ServiceDataItem { Name = item.Name, Status = item.Enabled });
}
if (success)
@ -114,7 +116,7 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.ServiceConfigurations
{
foreach (var item in new List<ServiceDataItem>(originalItems))
{
if (TrySet(item))
if (TrySetWithRetry(item))
{
originalItems.Remove(item);
}
@ -153,38 +155,56 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.ServiceConfigurations
return item;
}
private bool TrySetWithRetry(ServiceDataItem item)
{
var success = false;
if (IsAvailable(item))
{
for (var attempt = 1; attempt <= MAX_ATTEMPTS && !success; attempt++)
{
logger.Debug($"Attempt {attempt}/{MAX_ATTEMPTS} to set service {item}...");
success = TrySet(item);
}
if (!success)
{
logger.Error($"All attempts to set service {item} have failed!");
}
}
else
{
logger.Warn($"Cannot set service {item} as it does not exist!");
}
return success;
}
private bool TrySet(ServiceDataItem item)
{
var success = false;
try
{
if (IsAvailable(item))
using (var service = new ServiceController(item.Name))
{
using (var service = new ServiceController(item.Name))
if (item.Status == ServiceStatus.Running)
{
if (item.Status == ServiceStatus.Running)
{
success = TryStart(service);
}
else if (item.Status == ServiceStatus.Stopped)
{
success = TryStop(service);
}
if (success)
{
logger.Debug($"Successfully set service {item}.");
}
else
{
logger.Warn($"Could not set service {item}! Current status: {service.Status}.");
}
success = TryStart(service);
}
else if (item.Status == ServiceStatus.Stopped)
{
success = TryStop(service);
}
if (success)
{
logger.Debug($"Successfully set service {item}.");
}
else
{
logger.Warn($"Could not set service {item}! Current status: {service.Status}.");
}
}
else
{
logger.Warn($"Cannot set service {item} as it does not exist!");
}
}
catch (Exception e)
@ -197,11 +217,11 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.ServiceConfigurations
private bool TryStart(ServiceController service)
{
var success = true;
var success = false;
if (service.Status == ServiceControllerStatus.PausePending)
{
service.WaitForStatus(ServiceControllerStatus.Paused, TEN_SECONDS);
service.WaitForStatus(ServiceControllerStatus.Paused, FIVE_SECONDS);
service.Refresh();
}
@ -219,7 +239,7 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.ServiceConfigurations
if (service.Status == ServiceControllerStatus.StartPending || service.Status == ServiceControllerStatus.ContinuePending)
{
service.WaitForStatus(ServiceControllerStatus.Running, TEN_SECONDS);
service.WaitForStatus(ServiceControllerStatus.Running, FIVE_SECONDS);
service.Refresh();
}
@ -243,7 +263,7 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.ServiceConfigurations
if (service.Status == ServiceControllerStatus.StartPending || service.Status == ServiceControllerStatus.ContinuePending)
{
service.WaitForStatus(ServiceControllerStatus.Running, TEN_SECONDS);
service.WaitForStatus(ServiceControllerStatus.Running, FIVE_SECONDS);
service.Refresh();
}
@ -255,7 +275,7 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.ServiceConfigurations
if (service.Status == ServiceControllerStatus.StopPending)
{
service.WaitForStatus(ServiceControllerStatus.Stopped, TEN_SECONDS);
service.WaitForStatus(ServiceControllerStatus.Stopped, FIVE_SECONDS);
service.Refresh();
}
@ -269,7 +289,18 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.ServiceConfigurations
private bool IsAvailable(ServiceDataItem item)
{
return ServiceController.GetServices().Any(s => s.ServiceName == item.Name);
var available = false;
try
{
available = ServiceController.GetServices().Any(s => s.ServiceName == item.Name);
}
catch (Exception e)
{
logger.Error($"Failed to check whether service '{item.Name}' is available!", e);
}
return available;
}
private ServiceStatus ToStatus(ServiceControllerStatus status)