[LLDB][Telemetry]Define telemetry::CommandInfo (llvm#129354)

and collect telemetry about a command's execution.

*NOTE: Please consider this PR a DRAFT ( Waiting on PR/127696 to be
submitted. )

---------

Co-authored-by: Jonas Devlieghere <[email protected]>

Author: 2 people

lldb/include/lldb/Core/Telemetry.h

@@ -13,12 +13,14 @@
 #include "lldb/Interpreter/CommandReturnObject.h"
 #include "lldb/Utility/LLDBLog.h"
 #include "lldb/Utility/StructuredData.h"
+#include "lldb/Utility/UUID.h"
 #include "lldb/lldb-forward.h"
 #include "llvm/ADT/FunctionExtras.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/JSON.h"
 #include "llvm/Telemetry/Telemetry.h"
+#include <atomic>
 #include <chrono>
 #include <ctime>
 #include <memory>
@@ -28,6 +30,17 @@
 namespace lldb_private {
 namespace telemetry {
 
+struct LLDBConfig : public ::llvm::telemetry::Config {
+  // If true, we will collect full details about a debug command (eg., args and
+  // original command). Note: This may contain PII, hence can only be enabled by
+  // the vendor while creating the Manager.
+  const bool detailed_command_telemetry;
+
+  explicit LLDBConfig(bool enable_telemetry, bool detailed_command_telemetry)
+      : ::llvm::telemetry::Config(enable_telemetry),
+        detailed_command_telemetry(detailed_command_telemetry) {}
+};
+
 // We expect each (direct) subclass of LLDBTelemetryInfo to
 // have an LLDBEntryKind in the form 0b11xxxxxxxx
 // Specifically:
@@ -37,6 +50,7 @@ namespace telemetry {
 // must have their LLDBEntryKind in the similar form (ie., share common prefix)
 struct LLDBEntryKind : public ::llvm::telemetry::EntryKind {
   static const llvm::telemetry::KindType BaseInfo = 0b11000000;
+  static const llvm::telemetry::KindType CommandInfo = 0b11010000;
   static const llvm::telemetry::KindType DebuggerInfo = 0b11000100;
 };
 
@@ -66,6 +80,52 @@ struct LLDBBaseTelemetryInfo : public llvm::telemetry::TelemetryInfo {
   void serialize(llvm::telemetry::Serializer &serializer) const override;
 };
 
+struct CommandInfo : public LLDBBaseTelemetryInfo {
+  /// If the command is/can be associated with a target entry this field
+  /// contains that target's UUID. <EMPTY> otherwise.
+  UUID target_uuid;
+  /// A unique ID for a command so the manager can match the start entry with
+  /// its end entry. These values only need to be unique within the same
+  /// session. Necessary because we'd send off an entry right before a command's
+  /// execution and another right after. This is to avoid losing telemetry if
+  /// the command does not execute successfully.
+  uint64_t command_id;
+  /// The command name(eg., "breakpoint set")
+  std::string command_name;
+  /// These two fields are not collected by default due to PII risks.
+  /// Vendor may allow them by setting the
+  /// LLDBConfig::detailed_command_telemetry.
+  /// @{
+  std::optional<std::string> original_command;
+  std::optional<std::string> args;
+  /// @}
+  /// Return status of a command and any error description in case of error.
+  std::optional<lldb::ReturnStatus> ret_status;
+  std::optional<std::string> error_data;
+
+  CommandInfo() = default;
+
+  llvm::telemetry::KindType getKind() const override {
+    return LLDBEntryKind::CommandInfo;
+  }
+
+  static bool classof(const llvm::telemetry::TelemetryInfo *T) {
+    return (T->getKind() & LLDBEntryKind::CommandInfo) ==
+           LLDBEntryKind::CommandInfo;
+  }
+
+  void serialize(llvm::telemetry::Serializer &serializer) const override;
+
+  static uint64_t GetNextId();
+
+private:
+  // We assign each command (in the same session) a unique id so that their
+  // "start" and "end" entries can be matched up.
+  // These values don't need to be unique across runs (because they are
+  // secondary-key), hence a simple counter is sufficent.
+  static std::atomic<uint64_t> g_command_id_seed;
+};
+
 struct DebuggerInfo : public LLDBBaseTelemetryInfo {
   std::string lldb_version;
 
@@ -93,64 +153,76 @@ class TelemetryManager : public llvm::telemetry::Manager {
 public:
   llvm::Error preDispatch(llvm::telemetry::TelemetryInfo *entry) override;
 
-  const llvm::telemetry::Config *GetConfig();
+  const LLDBConfig *GetConfig() { return m_config.get(); }
 
   virtual llvm::StringRef GetInstanceName() const = 0;
 
   static TelemetryManager *GetInstance();
 
-  static TelemetryManager *GetInstanceIfEnabled();
-
 protected:
-  TelemetryManager(std::unique_ptr<llvm::telemetry::Config> config);
+  TelemetryManager(std::unique_ptr<LLDBConfig> config);
 
   static void SetInstance(std::unique_ptr<TelemetryManager> manger);
 
 private:
-  std::unique_ptr<llvm::telemetry::Config> m_config;
+  std::unique_ptr<LLDBConfig> m_config;
   // Each instance of a TelemetryManager is assigned a unique ID.
   const std::string m_id;
-
   static std::unique_ptr<TelemetryManager> g_instance;
 };
 
 /// Helper RAII class for collecting telemetry.
 template <typename Info> struct ScopedDispatcher {
   // The debugger pointer is optional because we may not have a debugger yet.
   // In that case, caller must set the debugger later.
-  ScopedDispatcher(llvm::unique_function<void(Info *info)> callback,
+  ScopedDispatcher(Debugger *debugger = nullptr) {
+    // Start the timer.
+    m_start_time = std::chrono::steady_clock::now();
+    this->debugger = debugger;
+  }
+  ScopedDispatcher(llvm::unique_function<void(Info *info)> final_callback,
                    Debugger *debugger = nullptr)
-      : m_callback(std::move(callback)) {
+      : m_final_callback(std::move(final_callback)) {
     // Start the timer.
     m_start_time = std::chrono::steady_clock::now();
-    m_info.debugger = debugger;
+    this->debugger = debugger;
   }
 
-  void SetDebugger(Debugger *debugger) { m_info.debugger = debugger; }
+  void SetDebugger(Debugger *debugger) { this->debugger = debugger; }
 
-  ~ScopedDispatcher() {
-    // If Telemetry is disabled (either at buildtime or runtime),
-    // then don't do anything.
-    TelemetryManager *manager = TelemetryManager::GetInstanceIfEnabled();
-    if (!manager)
-      return;
+  void DispatchOnExit(llvm::unique_function<void(Info *info)> final_callback) {
+    // We probably should not be overriding previously set cb.
+    assert(!m_final_callback);
+    m_final_callback = std::move(final_callback);
+  }
 
-    m_info.start_time = m_start_time;
-    // Populate common fields that we can only set now.
-    m_info.end_time = std::chrono::steady_clock::now();
-    // The callback will set the remaining fields.
-    m_callback(&m_info);
+  void DispatchNow(llvm::unique_function<void(Info *info)> populate_fields_cb) {
+    TelemetryManager *manager = TelemetryManager::GetInstance();
+    if (!manager->GetConfig()->EnableTelemetry)
+      return;
+    Info info;
+    // Populate the common fields we know about.
+    info.start_time = m_start_time;
+    info.end_time = std::chrono::steady_clock::now();
+    info.debugger = debugger;
+    // The callback will set the rest.
+    populate_fields_cb(&info);
     // And then we dispatch.
-    if (llvm::Error er = manager->dispatch(&m_info)) {
+    if (llvm::Error er = manager->dispatch(&info)) {
       LLDB_LOG_ERROR(GetLog(LLDBLog::Object), std::move(er),
-                     "Failed to dispatch entry of type: {0}", m_info.getKind());
+                     "Failed to dispatch entry of type: {0}", info.getKind());
     }
   }
 
+  ~ScopedDispatcher() {
+    if (m_final_callback)
+      DispatchNow(std::move(m_final_callback));
+  }
+
 private:
   SteadyTimePoint m_start_time;
-  llvm::unique_function<void(Info *info)> m_callback;
-  Info m_info;
+  llvm::unique_function<void(Info *info)> m_final_callback;
+  Debugger *debugger;
 };
 
 } // namespace telemetry

lldb/source/Core/Telemetry.cpp

@@ -60,14 +60,33 @@ void LLDBBaseTelemetryInfo::serialize(Serializer &serializer) const {
     serializer.write("end_time", ToNanosec(end_time.value()));
 }
 
+void CommandInfo::serialize(Serializer &serializer) const {
+  LLDBBaseTelemetryInfo::serialize(serializer);
+
+  serializer.write("target_uuid", target_uuid.GetAsString());
+  serializer.write("command_id", command_id);
+  serializer.write("command_name", command_name);
+  if (original_command.has_value())
+    serializer.write("original_command", original_command.value());
+  if (args.has_value())
+    serializer.write("args", args.value());
+  if (ret_status.has_value())
+    serializer.write("ret_status", ret_status.value());
+  if (error_data.has_value())
+    serializer.write("error_data", error_data.value());
+}
+
 void DebuggerInfo::serialize(Serializer &serializer) const {
   LLDBBaseTelemetryInfo::serialize(serializer);
 
   serializer.write("lldb_version", lldb_version);
   serializer.write("is_exit_entry", is_exit_entry);
 }
 
-TelemetryManager::TelemetryManager(std::unique_ptr<Config> config)
+std::atomic<uint64_t> CommandInfo::g_command_id_seed = 0;
+uint64_t CommandInfo::GetNextId() { return g_command_id_seed.fetch_add(1); }
+
+TelemetryManager::TelemetryManager(std::unique_ptr<LLDBConfig> config)
     : m_config(std::move(config)), m_id(MakeUUID()) {}
 
 llvm::Error TelemetryManager::preDispatch(TelemetryInfo *entry) {
@@ -79,23 +98,41 @@ llvm::Error TelemetryManager::preDispatch(TelemetryInfo *entry) {
   return llvm::Error::success();
 }
 
-const Config *TelemetryManager::GetConfig() { return m_config.get(); }
+class NoOpTelemetryManager : public TelemetryManager {
+public:
+  llvm::Error preDispatch(llvm::telemetry::TelemetryInfo *entry) override {
+    // Does nothing.
+    return llvm::Error::success();
+  }
 
-std::unique_ptr<TelemetryManager> TelemetryManager::g_instance = nullptr;
-TelemetryManager *TelemetryManager::GetInstance() {
-  if (!Config::BuildTimeEnableTelemetry)
-    return nullptr;
-  return g_instance.get();
-}
+  explicit NoOpTelemetryManager()
+      : TelemetryManager(std::make_unique<LLDBConfig>(
+            /*EnableTelemetry*/ false, /*DetailedCommand*/ false)) {}
+
+  virtual llvm::StringRef GetInstanceName() const override {
+    return "NoOpTelemetryManager";
+  }
+
+  llvm::Error dispatch(llvm::telemetry::TelemetryInfo *entry) override {
+    // Does nothing.
+    return llvm::Error::success();
+  }
 
-TelemetryManager *TelemetryManager::GetInstanceIfEnabled() {
-  // Telemetry may be enabled at build time but disabled at runtime.
-  if (TelemetryManager *ins = TelemetryManager::GetInstance()) {
-    if (ins->GetConfig()->EnableTelemetry)
-      return ins;
+  static NoOpTelemetryManager *GetInstance() {
+    static std::unique_ptr<NoOpTelemetryManager> g_ins =
+        std::make_unique<NoOpTelemetryManager>();
+    return g_ins.get();
   }
+};
 
-  return nullptr;
+std::unique_ptr<TelemetryManager> TelemetryManager::g_instance = nullptr;
+TelemetryManager *TelemetryManager::GetInstance() {
+  // If Telemetry is disabled or if there is no default instance, then use the
+  // NoOp manager. We use a dummy instance to avoid having to do nullchecks in
+  // various places.
+  if (!Config::BuildTimeEnableTelemetry || !g_instance)
+    return NoOpTelemetryManager::GetInstance();
+  return g_instance.get();
 }
 
 void TelemetryManager::SetInstance(std::unique_ptr<TelemetryManager> manager) {