/// <summary>
/// Invoked by a Cache instance on updating, using properties from the PollNode such as connection strings, etc.
/// </summary>
/// <typeparam name="T">Type of item in the cache</typeparam>
/// <param name="description">Description of the operation, used purely for profiling</param>
/// <param name="getData">The operation used to actually get data, e.g. <code>using (var conn = GetConnectionAsync()) { return getFromConnection(conn); }</code></param>
/// <param name="logExceptions">Whether to log any exceptions to the log</param>
/// <param name="addExceptionData">Optionally add exception data, e.g. <code>e => e.AddLoggedData("Server", Name)</code></param>
/// <returns>A cache update action, used when creating a <see cref="Cache"/>.</returns>
protected Action <Cache <T> > UpdateCacheItem <T>(string description,
Func <Task <T> > getData,
bool logExceptions = false, // TODO: Settings
Action <Exception> addExceptionData = null) where T : class
{
return(async cache =>
{
if (OpserverProfileProvider.EnablePollerProfiling)
{
cache.Profiler = OpserverProfileProvider.CreateContextProfiler("Poll: " + description, cache.UniqueId);
}
using (MiniProfiler.Current.Step(description))
{
CacheItemFetching?.Invoke(this, EventArgs.Empty);
try
{
using (MiniProfiler.Current.Step("Data Fetch"))
{
cache.Data = await getData();
}
cache.LastSuccess = cache.LastPoll = DateTime.UtcNow;
cache.ErrorMessage = "";
PollFailsInaRow = 0;
}
catch (Exception e)
{
var deserializationException = e as DeserializationException;
if (deserializationException != null)
{
e.AddLoggedData("Snippet-After", deserializationException.SnippetAfterError)
.AddLoggedData("Position", deserializationException.Position.ToString())
.AddLoggedData("Ended-Unexpectedly", deserializationException.EndedUnexpectedly.ToString());
}
if (logExceptions)
{
addExceptionData?.Invoke(e);
Current.LogException(e);
}
cache.LastPoll = DateTime.UtcNow;
PollFailsInaRow++;
cache.ErrorMessage = "Unable to fetch from " + NodeType + ": " + e.Message;
#if DEBUG
cache.ErrorMessage += " @ " + e.StackTrace;
#endif
if (e.InnerException != null)
{
cache.ErrorMessage += "\n" + e.InnerException.Message;
}
}
CacheItemFetched?.Invoke(this, EventArgs.Empty);
CachedMonitorStatus = null;
}
if (OpserverProfileProvider.EnablePollerProfiling)
{
OpserverProfileProvider.StopContextProfiler();
}
});
}
/// <summary>
/// Invoked by a Cache instance on updating, using properties from the PollNode such as connection strings, etc.
/// </summary>
/// <typeparam name="T">Type of item in the cache</typeparam>
/// <param name="description">Description of the operation, used purely for profiling</param>
/// <param name="getData">The operation used to actually get data, e.g. <code>using (var conn = GetConnectionAsync()) { return getFromConnection(conn); }</code></param>
/// <param name="logExceptions">Whether to log any exceptions to the log</param>
/// <param name="addExceptionData">Optionally add exception data, e.g. <code>e => e.AddLoggedData("Server", Name)</code></param>
/// <param name="timeoutMs">The timeout in milliseconds for this poll to complete before aborting.</param>
/// <param name="afterPoll">An optional action to run after polling has completed successfully</param>
/// <returns>A cache update action, used when creating a <see cref="Cache"/>.</returns>
protected Func <Cache <T>, Task> UpdateCacheItem <T>(string description,
Func <Task <T> > getData,
bool logExceptions = false, // TODO: Settings
Action <Exception> addExceptionData = null,
int?timeoutMs = null,
Action <Cache <T> > afterPoll = null) where T : class
{
return(async cache =>
{
cache.PollStatus = "UpdateCacheItem";
if (OpserverProfileProvider.EnablePollerProfiling)
{
cache.Profiler = OpserverProfileProvider.CreateContextProfiler("Poll: " + description, cache.UniqueId, store: false);
}
using (MiniProfiler.Current.Step(description))
{
CacheItemFetching?.Invoke(this, EventArgs.Empty);
try
{
cache.PollStatus = "Fetching";
using (MiniProfiler.Current.Step("Data Fetch"))
{
var fetch = getData();
if (timeoutMs.HasValue)
{
if (await Task.WhenAny(fetch, Task.Delay(timeoutMs.Value)) == fetch)
{
// Re-await for throws.
cache.SetData(await fetch.ConfigureAwait(false));
}
else
{
throw new TimeoutException($"Fetch timed out after {timeoutMs.ToString()} ms.");
}
}
else
{
cache.SetData(await fetch.ConfigureAwait(false));
}
}
cache.PollStatus = "Fetch Complete";
cache.SetSuccess();
PollFailsInaRow = 0;
afterPoll?.Invoke(cache);
}
catch (Exception e)
{
if (logExceptions)
{
addExceptionData?.Invoke(e);
Current.LogException(e);
}
PollFailsInaRow++;
var errorMessage = "Unable to fetch from " + NodeType + ": " + e.Message;
#if DEBUG
errorMessage += " @ " + e.StackTrace;
#endif
if (e.InnerException != null)
{
errorMessage += "\n" + e.InnerException.Message;
}
cache.PollStatus = "Fetch Failed";
cache.SetFail(errorMessage);
}
CacheItemFetched?.Invoke(this, EventArgs.Empty);
CachedMonitorStatus = null;
LastFetch = cache;
}
if (OpserverProfileProvider.EnablePollerProfiling)
{
OpserverProfileProvider.StopContextProfiler();
}
cache.PollStatus = "UpdateCacheItem Complete";
});
}
