private static ITraceWriter CreateTraceWriter(TracerSettings settings, IDogStatsd statsd)
{
IMetrics metrics = statsd != null
? new DogStatsdMetrics(statsd)
: new NullMetrics();
switch (settings.Exporter)
{
case ExporterType.Zipkin:
return(new ExporterWriter(new ZipkinExporter(settings.AgentUri), metrics));
case ExporterType.Jaeger:
return(new ExporterWriter(new JaegerExporter(JaegerOptions.FromTracerSettings(settings)), metrics));
default:
return(new AgentWriter(new Api(settings.AgentUri, TransportStrategy.Get(settings), statsd), metrics, maxBufferSize: settings.TraceBufferSize));
}
}
internal Tracer(TracerSettings settings, IAgentWriter agentWriter, ISampler sampler, IScopeManager scopeManager, IDogStatsd statsd)
{
// update the count of Tracer instances
Interlocked.Increment(ref _liveTracerCount);
Settings = settings ?? TracerSettings.FromDefaultSources();
Settings.Freeze();
// if not configured, try to determine an appropriate service name
DefaultServiceName = Settings.ServiceName ??
GetApplicationName() ??
UnknownServiceName;
// only set DogStatsdClient if tracer metrics are enabled
if (Settings.TracerMetricsEnabled)
{
Statsd = statsd ?? CreateDogStatsdClient(Settings, DefaultServiceName, Settings.DogStatsdPort);
}
// fall back to default implementations of each dependency if not provided
if (agentWriter != null)
{
_agentWriter = agentWriter;
}
else
{
IApi api = null;
switch (Settings.Exporter)
{
case ExporterType.Zipkin:
api = new ZipkinApi(Settings);
break;
case ExporterType.DatadogAgent:
default:
api = new Api(Settings.AgentUri, TransportStrategy.Get(Settings), Statsd);
break;
}
_agentWriter = new AgentWriter(api, Statsd, queueSize: Settings.TraceQueueSize);
}
_scopeManager = scopeManager ?? new AsyncLocalScopeManager();
Sampler = sampler ?? new RuleBasedSampler(new RateLimiter(Settings.MaxTracesSubmittedPerSecond));
if (!string.IsNullOrWhiteSpace(Settings.CustomSamplingRules))
{
foreach (var rule in CustomSamplingRule.BuildFromConfigurationString(Settings.CustomSamplingRules))
{
Sampler.RegisterRule(rule);
}
}
if (Settings.GlobalSamplingRate != null)
{
var globalRate = (float)Settings.GlobalSamplingRate;
if (globalRate < 0f || globalRate > 1f)
{
Log.Warning("{ConfigurationKey} configuration of {ConfigurationValue} is out of range", ConfigurationKeys.GlobalSamplingRate, Settings.GlobalSamplingRate);
}
else
{
Sampler.RegisterRule(new GlobalSamplingRule(globalRate));
}
}
// Register callbacks to make sure we flush the traces before exiting
AppDomain.CurrentDomain.ProcessExit += CurrentDomain_ProcessExit;
AppDomain.CurrentDomain.DomainUnload += CurrentDomain_DomainUnload;
try
{
// Registering for the AppDomain.UnhandledException event cannot be called by a security transparent method
// This will only happen if the Tracer is not run full-trust
AppDomain.CurrentDomain.UnhandledException += CurrentDomain_UnhandledException;
}
catch (Exception ex)
{
Log.Warning(ex, "Unable to register a callback to the AppDomain.UnhandledException event.");
}
try
{
// Registering for the cancel key press event requires the System.Security.Permissions.UIPermission
Console.CancelKeyPress += Console_CancelKeyPress;
}
catch (Exception ex)
{
Log.Warning(ex, "Unable to register a callback to the Console.CancelKeyPress event.");
}
// start the heartbeat loop
_heartbeatTimer = new Timer(HeartbeatCallback, state: null, dueTime: TimeSpan.Zero, period: TimeSpan.FromMinutes(1));
// If configured, add/remove the correlation identifiers into the
// LibLog logging context when a scope is activated/closed
if (Settings.LogsInjectionEnabled)
{
InitializeLibLogScopeEventSubscriber(_scopeManager, DefaultServiceName, Settings.ServiceVersion, Settings.Environment);
}
if (Interlocked.Exchange(ref _firstInitialization, 0) == 1)
{
if (Settings.StartupDiagnosticLogEnabled)
{
_ = Task.Run(WriteDiagnosticLog);
}
if (Settings.RuntimeMetricsEnabled)
{
_runtimeMetricsWriter = new RuntimeMetricsWriter(Statsd ?? CreateDogStatsdClient(Settings, DefaultServiceName, Settings.DogStatsdPort), TimeSpan.FromSeconds(10));
}
}
}