avoid allocating strings and params arrays if we can't log or debug is disabled

Author: lucaspimentel

tracer/src/Datadog.Trace.ClrProfiler.Managed.Loader/Startup.cs

@@ -62,15 +62,15 @@ static Startup()
 
                 if (tracerHomeDirectory is null)
                 {
-                    StartupLogger.Log($"{TracerHomePathKey} not set. Datadog SDK will be disabled.");
+                    StartupLogger.Log("{0} not set. Datadog SDK will be disabled.", TracerHomePathKey);
                     return;
                 }
 
                 ManagedProfilerDirectory = ComputeTfmDirectory(tracerHomeDirectory);
 
                 if (!Directory.Exists(ManagedProfilerDirectory))
                 {
-                    StartupLogger.Log($"Datadog.Trace.dll TFM directory not found at '{ManagedProfilerDirectory}'. Datadog SDK will be disabled.");
+                    StartupLogger.Log("Datadog.Trace.dll TFM directory not found at '{0}'. Datadog SDK will be disabled.", ManagedProfilerDirectory);
                     return;
                 }
 
@@ -103,14 +103,14 @@ static Startup()
                 {
                     // With V3, pretty much all scenarios require the trace-agent and dogstatsd, so we enable them by default
                     const string processManagerTypeName = "Datadog.Trace.AgentProcessManager";
-                    StartupLogger.Log($"Invoking {processManagerTypeName}.{methodName}() to start external processes.");
+                    StartupLogger.Log("Invoking {0}.{1}() to start external processes.", processManagerTypeName, methodName);
                     TryInvokeManagedMethod(processManagerTypeName, methodName, "Datadog.Trace.AgentProcessManagerLoader");
                 }
 
                 // We need to initialize the managed tracer regardless of whether tracing is enabled
                 // because other products rely on it
                 const string instrumentationTypeName = "Datadog.Trace.ClrProfiler.Instrumentation";
-                StartupLogger.Log($"Invoking {instrumentationTypeName}.{methodName}() to initialize instrumentation.");
+                StartupLogger.Log("Invoking {0}.{1}() to initialize instrumentation.", instrumentationTypeName, methodName);
                 TryInvokeManagedMethod(instrumentationTypeName, methodName, "Datadog.Trace.ClrProfiler.InstrumentationLoader");
             }
             catch (Exception ex)

tracer/src/Datadog.Trace.ClrProfiler.Managed.Loader/StartupLogger.cs

@@ -40,7 +40,27 @@ static StartupLogger()
             }
         }
 
-        public static void Log(string message, params object?[] args)
+        public static void Log(string message)
+        {
+            LogCore(message, null);
+        }
+
+        public static void Log(string message, object? arg0)
+        {
+            LogCore(message, [arg0]);
+        }
+
+        public static void Log(string message, object? arg0, object? arg1)
+        {
+            LogCore(message, [arg0, arg1]);
+        }
+
+        public static void Log(string message, object? arg0, object? arg1, object? arg2)
+        {
+            LogCore(message, [arg0, arg1, arg2]);
+        }
+
+        private static void LogCore(string message, object?[]? args)
         {
             if (StartupLogFilePath == null)
             {
@@ -52,6 +72,7 @@ public static void Log(string message, params object?[] args)
                 lock (PadLock)
                 {
                     using var fileSink = new FileSink(StartupLogFilePath);
+
                     if (DebugEnabled)
                     {
                         var currentDomain = AppDomain.CurrentDomain;
@@ -72,14 +93,40 @@ public static void Log(string message, params object?[] args)
 
         public static void Log(Exception ex, string message, params object?[] args)
         {
-            Log($"{message}{Environment.NewLine}{ex}", args);
+            // Format the message first, then append exception
+            var formattedMessage = args.Length > 0 ? string.Format(message, args) : message;
+            Log("{0}{1}{2}", formattedMessage, Environment.NewLine, ex);
+        }
+
+        public static void Debug(string message)
+        {
+            if (DebugEnabled)
+            {
+                LogCore(message, null);
+            }
+        }
+
+        public static void Debug(string message, object? arg0)
+        {
+            if (DebugEnabled)
+            {
+                LogCore(message, [arg0]);
+            }
+        }
+
+        public static void Debug(string message, object? arg0, object? arg1)
+        {
+            if (DebugEnabled)
+            {
+                LogCore(message, [arg0, arg1]);
+            }
         }
 
-        public static void Debug(string message, params object?[] args)
+        public static void Debug(string message, object? arg0, object? arg1, object? arg2)
         {
             if (DebugEnabled)
             {
-                Log(message, args);
+                LogCore(message, [arg0, arg1, arg2]);
             }
         }
 
@@ -141,12 +188,14 @@ private static string ComputeStartupLogFilePath(string logDirectory)
             {
                 // Do our best to not block other processes on write by using the process name and id
                 using var process = Process.GetCurrentProcess();
-                return Path.Combine(logDirectory, $"dotnet-tracer-loader-{process.ProcessName}-{process.Id}.log");
+                var fileName = string.Concat("dotnet-tracer-loader-", process.ProcessName, "-", process.Id.ToString(), ".log");
+                return Path.Combine(logDirectory, fileName);
             }
             catch
             {
                 // We can't get the process info, use a random guid instead
-                return Path.Combine(logDirectory, $"dotnet-tracer-loader-{Guid.NewGuid()}.log");
+                var fileName = string.Concat("dotnet-tracer-loader-", Guid.NewGuid().ToString(), ".log");
+                return Path.Combine(logDirectory, fileName);
             }
         }
     }