private static string ReadEnvironmentVariable(string key)
{
try
{
return(Environment.GetEnvironmentVariable(key));
}
catch (Exception ex)
{
StartupLogger.Log(ex, "Error while loading environment variable " + key);
}
return(null);
}
/// <summary>
/// Initializes static members of the <see cref="Startup"/> class.
/// This method also attempts to load the Datadog.Trace.ClrProfiler.Managed .NET assembly.
/// </summary>
static Startup()
{
ManagedProfilerDirectory = ResolveManagedProfilerDirectory();
try
{
AppDomain.CurrentDomain.AssemblyResolve += AssemblyResolve_ManagedProfilerDependencies;
}
catch (Exception ex)
{
StartupLogger.Log(ex, "Unable to register a callback to the CurrentDomain.AssemblyResolve event.");
}
TryLoadManagedAssembly();
}
private static void TryInvokeManagedMethod(string typeName, string methodName)
{
try
{
var assembly = Assembly.Load(AssemblyName);
if (assembly != null)
{
var type = assembly.GetType(typeName, throwOnError: false);
var method = type?.GetRuntimeMethod(methodName, parameters: Type.EmptyTypes);
method?.Invoke(obj: null, parameters: null);
}
}
catch (Exception ex)
{
StartupLogger.Log(ex, "Error when invoking managed method: {0}.{1}", typeName, methodName);
}
}
private static void TryLoadManagedAssembly()
{
try
{
var assembly = Assembly.Load("Datadog.Trace.ClrProfiler.Managed, Version=1.26.3.0, Culture=neutral, PublicKeyToken=def86d061d0d2eeb");
if (assembly != null)
{
// call method Datadog.Trace.ClrProfiler.Instrumentation.Initialize()
var type = assembly.GetType("Datadog.Trace.ClrProfiler.Instrumentation", throwOnError: false);
var method = type?.GetRuntimeMethod("Initialize", parameters: new Type[0]);
method?.Invoke(obj: null, parameters: null);
}
}
catch (Exception ex)
{
StartupLogger.Log(ex, "Error when loading managed assemblies.");
}
}
private static Assembly LoadAssembly(string assemblyString)
{
try
{
return(Assembly.Load(assemblyString));
}
catch (FileNotFoundException ex)
{
// In some IIS scenarios the `AssemblyResolve` event doesn't get triggered and we received this exception.
// We will try to resolve it manually as a last chance.
StartupLogger.Log(ex, "Error on assembly load: {0}, Trying to solve it manually...", assemblyString);
var assembly = ResolveAssembly(assemblyString);
if (assembly is not null)
{
StartupLogger.Log("Assembly resolved manually.");
}
return(assembly);
}
}
private static void TryInvokeManagedMethod(string typeName, string methodName)
{
try
{
var assembly = LoadAssembly(AssemblyName);
if (assembly == null)
{
StartupLogger.Log("Assembly '{0}' cannot be loaded. The managed method ({1}.{2}) cannot be invoked", AssemblyName, typeName, methodName);
return;
}
var type = assembly.GetType(typeName, throwOnError: false);
var method = type?.GetRuntimeMethod(methodName, parameters: Type.EmptyTypes);
method?.Invoke(obj: null, parameters: null);
}
catch (Exception ex)
{
StartupLogger.Log(ex, "Error when invoking managed method: {0}.{1}", typeName, methodName);
}
}
/// <summary>
/// Initializes static members of the <see cref="Startup"/> class.
/// This method also attempts to load the SignalFx.TracingTrace .NET assembly.
/// </summary>
static Startup()
{
ManagedProfilerDirectory = ResolveManagedProfilerDirectory();
StartupLogger.Debug("Resolving managed profiler directory to: {0}", ManagedProfilerDirectory);
try
{
AppDomain.CurrentDomain.AssemblyResolve += AssemblyResolve_ManagedProfilerDependencies;
}
catch (Exception ex)
{
StartupLogger.Log(ex, "Unable to register a callback to the CurrentDomain.AssemblyResolve event.");
}
var runInAas = ReadBooleanEnvironmentVariable(AzureAppServicesKey, false);
if (!runInAas)
{
TryInvokeManagedMethod("Datadog.Trace.ClrProfiler.Instrumentation", "Initialize");
return;
}
// In AAS, the loader can be used to load the tracer, the traceagent only (if only custom tracing is enabled),
// dogstatsd or all of them.
var customTracingEnabled = ReadBooleanEnvironmentVariable(AasCustomTracingKey, false);
var needsDogStatsD = ReadBooleanEnvironmentVariable(AasCustomMetricsKey, false);
var automaticTraceEnabled = ReadBooleanEnvironmentVariable(TraceEnabledKey, true);
if (automaticTraceEnabled || customTracingEnabled || needsDogStatsD)
{
StartupLogger.Log("Invoking managed method to start external processes.");
TryInvokeManagedMethod("Datadog.Trace.AgentProcessManager", "Initialize");
}
if (automaticTraceEnabled)
{
StartupLogger.Log("Invoking managed tracer.");
TryInvokeManagedMethod("Datadog.Trace.ClrProfiler.Instrumentation", "Initialize");
}
}
