public void RunAndBlock(CancellationToken cancellationToken = default(CancellationToken))
{
_consecutiveErrorCount = 0;
do
{
ScriptHost newInstance = null;
try
{
// if we were in an error state retain that,
// otherwise move to default
if (State != ScriptHostState.Error)
{
State = ScriptHostState.Default;
}
// Create a new host config, but keep the host id from existing one
_config.HostConfig = new JobHostConfiguration(_settingsManager.Configuration)
{
HostId = _config.HostConfig.HostId
};
OnInitializeConfig(_config);
newInstance = _scriptHostFactory.Create(_environment, EventManager, _settingsManager, _config, _loggerProviderFactory);
_currentInstance = newInstance;
lock (_liveInstances)
{
_liveInstances.Add(newInstance);
_hostStartCount++;
}
newInstance.HostInitializing += OnHostInitializing;
newInstance.HostInitialized += OnHostInitialized;
newInstance.HostStarted += OnHostStarted;
newInstance.Initialize();
newInstance.StartAsync(cancellationToken).GetAwaiter().GetResult();
// log any function initialization errors
LogErrors(newInstance);
LastError = null;
_consecutiveErrorCount = 0;
_restartDelayTokenSource = null;
// Wait for a restart signal. This event will automatically reset.
// While we're restarting, it is possible for another restart to be
// signaled. That is fine - the restart will be processed immediately
// once we get to this line again. The important thing is that these
// restarts are only happening on a single thread.
var waitHandles = new WaitHandle[] { cancellationToken.WaitHandle, _restartHostEvent, _stopEvent };
if (!waitHandles.Any(p => p.SafeWaitHandle.IsClosed))
{
WaitHandle.WaitAny(waitHandles);
}
// Orphan the current host instance. We're stopping it, so it won't listen for any new functions
// it will finish any currently executing functions and then clean itself up.
// Spin around and create a new host instance.
Task.Run(() => Orphan(newInstance)
.ContinueWith(t =>
{
if (t.IsFaulted)
{
t.Exception.Handle(e => true);
}
}, TaskContinuationOptions.ExecuteSynchronously));
}
catch (Exception ex)
{
if (_disposed)
{
// In some cases during shutdown we'll be disposed and get
// some terminating exceptions. We want to just ignore these
// and stop immediately.
break;
}
State = ScriptHostState.Error;
LastError = ex;
_consecutiveErrorCount++;
// We need to keep the host running, so we catch and log any errors
// then restart the host
string message = "A ScriptHost error has occurred";
Instance?.Logger.LogError(0, ex, message);
if (ShutdownHostIfUnhealthy())
{
break;
}
// If a ScriptHost instance was created before the exception was thrown
// Orphan and cleanup that instance.
if (newInstance != null)
{
Task.Run(() => Orphan(newInstance, forceStop: true)
.ContinueWith(t =>
{
if (t.IsFaulted)
{
t.Exception.Handle(e => true);
}
}, TaskContinuationOptions.ExecuteSynchronously));
}
// attempt restarts using an exponential backoff strategy
CreateRestartBackoffDelay(_consecutiveErrorCount).GetAwaiter().GetResult();
}
}while (!_stopped && !_disposed && !cancellationToken.IsCancellationRequested);
}
