feat(logging): add spdlog backend behind ICEBERG_SPDLOG (5/6)

CMakeLists.txt

@@ -54,6 +54,7 @@ option(ICEBERG_S3 "Build with S3 support" OFF)
 option(ICEBERG_SIGV4 "Build with SigV4 support" OFF)
 option(ICEBERG_BUNDLE_AWSSDK "Bundle AWS SDK for S3/SigV4 support" ON)
 option(ICEBERG_BUNDLE_THRIFT "Bundle Thrift (from Arrow) for Hive catalog" ON)
+option(ICEBERG_SPDLOG "Use spdlog as the default logging backend" ON)
 option(ICEBERG_ENABLE_ASAN "Enable Address Sanitizer" OFF)
 option(ICEBERG_ENABLE_UBSAN "Enable Undefined Behavior Sanitizer" OFF)
 

cmake_modules/IcebergThirdpartyToolchain.cmake

@@ -869,7 +869,9 @@ resolve_nanoarrow_dependency()
 resolve_croaring_dependency()
 resolve_utf8proc_dependency()
 resolve_nlohmann_json_dependency()
-resolve_spdlog_dependency()
+if(ICEBERG_SPDLOG)
+  resolve_spdlog_dependency()
+endif()
 
 if(ICEBERG_S3 OR ICEBERG_SIGV4)
   if(ICEBERG_SIGV4 AND NOT ICEBERG_BUILD_REST)

meson.options

@@ -51,6 +51,13 @@ option(
     value: 'disabled',
 )
 
+option(
+    'spdlog',
+    type: 'feature',
+    description: 'Use spdlog as the default logging backend (CMake: ICEBERG_SPDLOG)',
+    value: 'enabled',
+)
+
 option('tests', type: 'feature', description: 'Build tests', value: 'enabled')
 
 option(

src/iceberg/CMakeLists.txt

@@ -17,6 +17,18 @@
 
 set(ICEBERG_INCLUDES "$<BUILD_INTERFACE:${PROJECT_BINARY_DIR}/src>"
                      "$<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/src>")
+
+# Generate the logging backend config header. ALWAYS generated (not gated by
+# ICEBERG_SPDLOG) so logging/logger.cc can include it in both ON and OFF builds;
+# only the definedness of ICEBERG_HAS_SPDLOG varies. Generated into the build
+# tree (already on ICEBERG_INCLUDES), included as "iceberg/logging/config.h", and
+# NOT installed (it must never appear in a public/installed header).
+if(ICEBERG_SPDLOG)
+  set(ICEBERG_HAS_SPDLOG ON)
+endif()
+configure_file("${CMAKE_CURRENT_SOURCE_DIR}/logging/config.h.in"
+               "${CMAKE_CURRENT_BINARY_DIR}/logging/config.h")
+
 set(ICEBERG_SOURCES
     arrow_c_data_guard_internal.cc
     arrow_c_data_util.cc
@@ -157,29 +169,37 @@ list(APPEND
      ICEBERG_STATIC_BUILD_INTERFACE_LIBS
      "$<IF:$<BOOL:${NANOARROW_VENDORED}>,nanoarrow::nanoarrow_static,$<IF:$<TARGET_EXISTS:nanoarrow::nanoarrow_static>,nanoarrow::nanoarrow_static,nanoarrow::nanoarrow_shared>>"
      nlohmann_json::nlohmann_json
-     spdlog::spdlog
      utf8proc::utf8proc
      ZLIB::ZLIB)
 list(APPEND
      ICEBERG_SHARED_BUILD_INTERFACE_LIBS
      "$<IF:$<BOOL:${NANOARROW_VENDORED}>,nanoarrow::nanoarrow_static,$<IF:$<TARGET_EXISTS:nanoarrow::nanoarrow_shared>,nanoarrow::nanoarrow_shared,nanoarrow::nanoarrow_static>>"
      nlohmann_json::nlohmann_json
-     spdlog::spdlog
      utf8proc::utf8proc
      ZLIB::ZLIB)
 list(APPEND
      ICEBERG_STATIC_INSTALL_INTERFACE_LIBS
      "$<IF:$<BOOL:${NANOARROW_VENDORED}>,iceberg::nanoarrow_static,$<IF:$<TARGET_EXISTS:nanoarrow::nanoarrow_static>,nanoarrow::nanoarrow_static,nanoarrow::nanoarrow_shared>>"
      "$<IF:$<BOOL:${NLOHMANN_JSON_VENDORED}>,iceberg::nlohmann_json,$<IF:$<TARGET_EXISTS:nlohmann_json::nlohmann_json>,nlohmann_json::nlohmann_json,nlohmann_json::nlohmann_json>>"
-     "$<IF:$<BOOL:${SPDLOG_VENDORED}>,iceberg::spdlog,spdlog::spdlog>"
      "$<IF:$<BOOL:${UTF8PROC_VENDORED}>,iceberg::utf8proc,utf8proc::utf8proc>")
 list(APPEND
      ICEBERG_SHARED_INSTALL_INTERFACE_LIBS
      "$<IF:$<BOOL:${NANOARROW_VENDORED}>,iceberg::nanoarrow_static,$<IF:$<TARGET_EXISTS:nanoarrow::nanoarrow_shared>,nanoarrow::nanoarrow_shared,nanoarrow::nanoarrow_static>>"
      "$<IF:$<BOOL:${NLOHMANN_JSON_VENDORED}>,iceberg::nlohmann_json,$<IF:$<TARGET_EXISTS:nlohmann_json::nlohmann_json>,nlohmann_json::nlohmann_json,nlohmann_json::nlohmann_json>>"
-     "$<IF:$<BOOL:${SPDLOG_VENDORED}>,iceberg::spdlog,spdlog::spdlog>"
      "$<IF:$<BOOL:${UTF8PROC_VENDORED}>,iceberg::utf8proc,utf8proc::utf8proc>")
 
+# spdlog backend: linked and compiled only when ICEBERG_SPDLOG is ON. When OFF,
+# the core library has no spdlog dependency and CerrLogger is the default sink.
+if(ICEBERG_SPDLOG)
+  list(APPEND ICEBERG_SOURCES logging/internal/spdlog_logger.cc)
+  list(APPEND ICEBERG_STATIC_BUILD_INTERFACE_LIBS spdlog::spdlog)
+  list(APPEND ICEBERG_SHARED_BUILD_INTERFACE_LIBS spdlog::spdlog)
+  list(APPEND ICEBERG_STATIC_INSTALL_INTERFACE_LIBS
+       "$<IF:$<BOOL:${SPDLOG_VENDORED}>,iceberg::spdlog,spdlog::spdlog>")
+  list(APPEND ICEBERG_SHARED_INSTALL_INTERFACE_LIBS
+       "$<IF:$<BOOL:${SPDLOG_VENDORED}>,iceberg::spdlog,spdlog::spdlog>")
+endif()
+
 add_iceberg_lib(iceberg
                 SOURCES
                 ${ICEBERG_SOURCES}

src/iceberg/logging/config.h.in

@@ -0,0 +1,30 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#pragma once
+
+// Internal, build-generated configuration for the logging backend.
+// This header is NOT installed and must only be included from .cc files
+// (logger.cc, internal/spdlog_logger.cc) -- never from a public header.
+//
+// ICEBERG_HAS_SPDLOG is defined when the project is built with -DICEBERG_SPDLOG=ON
+// and left undefined otherwise. Always test it with #ifdef / #ifndef, never #if
+// (it carries no value).
+
+#cmakedefine ICEBERG_HAS_SPDLOG

src/iceberg/logging/internal/spdlog_logger.cc

@@ -0,0 +1,115 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "iceberg/logging/internal/spdlog_logger.h"
+
+#ifdef ICEBERG_HAS_SPDLOG
+
+#  include <memory>
+#  include <string>
+#  include <unordered_map>
+#  include <utility>
+
+#  include <spdlog/common.h>
+#  include <spdlog/sinks/stdout_color_sinks.h>
+
+namespace iceberg::internal {
+
+namespace {
+
+spdlog::level::level_enum ToSpdLevel(LogLevel level) noexcept {
+  switch (level) {
+    case LogLevel::kTrace:
+      return spdlog::level::trace;
+    case LogLevel::kDebug:
+      return spdlog::level::debug;
+    case LogLevel::kInfo:
+      return spdlog::level::info;
+    case LogLevel::kWarn:
+      return spdlog::level::warn;
+    case LogLevel::kError:
+      return spdlog::level::err;
+    case LogLevel::kCritical:
+    case LogLevel::kFatal:
+      // spdlog has no "fatal"; the process abort is owned by the macro layer.
+      return spdlog::level::critical;
+    case LogLevel::kOff:
+      return spdlog::level::off;
+  }
+  return spdlog::level::off;
+}
+
+/// \brief The built-in sink: a color stderr spdlog logger.
+std::shared_ptr<spdlog::logger> MakeDefaultSpdLogger() {
+  return std::make_shared<spdlog::logger>(
+      "iceberg", std::make_shared<spdlog::sinks::stderr_color_sink_mt>());
+}
+
+}  // namespace
+
+SpdLogger::SpdLogger(LogLevel level) : SpdLogger(MakeDefaultSpdLogger(), level) {}
+
+Status SpdLogger::Initialize(
+    const std::unordered_map<std::string, std::string>& properties) {
+  if (auto it = properties.find(std::string(kPatternProperty)); it != properties.end()) {
+    logger_->set_pattern(it->second);
+  }
+  // Apply "level" via the base implementation.
+  return Logger::Initialize(properties);
+}
+
+SpdLogger::SpdLogger(std::shared_ptr<spdlog::logger> logger, LogLevel level)
+    : logger_(std::move(logger)), level_(level) {
+  // logger_ is non-null for the rest of this object's life, so Initialize/Log/Flush
+  // may dereference it unconditionally. Enforced by substitution rather than an
+  // assertion, which would vanish under NDEBUG and leave a release-build crash: a
+  // null argument falls back to the same stderr-backed logger the default
+  // constructor builds, so a caller mistake degrades to the default sink.
+  if (!logger_) {
+    logger_ = MakeDefaultSpdLogger();
+  }
+  logger_->set_level(spdlog::level::trace);  // filtering is done by ShouldLog
+}
+
+void SpdLogger::Log(LogMessage&& message) noexcept {
+  try {
+    spdlog::source_loc loc{message.location.file_name(),
+                           static_cast<int>(message.location.line()),
+                           message.location.function_name()};
+    // Raw-message overload: the text is already formatted, so hand spdlog the bytes
+    // directly instead of running them back through fmt (which would re-parse and
+    // copy the whole message, allocating for long ones). It also means braces in the
+    // message can never be interpreted as format placeholders.
+    logger_->log(loc, ToSpdLevel(message.level),
+                 spdlog::string_view_t{message.message.data(), message.message.size()});
+  } catch (...) {
+    // Logging must never throw.
+  }
+}
+
+void SpdLogger::Flush() noexcept {
+  try {
+    logger_->flush();
+  } catch (...) {
+  }
+}
+
+}  // namespace iceberg::internal
+
+#endif  // ICEBERG_HAS_SPDLOG

src/iceberg/logging/internal/spdlog_logger.h

@@ -0,0 +1,90 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#pragma once
+
+/// \file iceberg/logging/internal/spdlog_logger.h
+/// \brief spdlog-backed logging sink.
+///
+/// INTERNAL, NOT INSTALLED. Included only from .cc files (logger.cc and
+/// spdlog_logger.cc). It pulls in the build-generated config.h itself and gates
+/// its entire body on ICEBERG_HAS_SPDLOG, so it compiles to nothing unless the
+/// project was built with ICEBERG_SPDLOG=ON. SpdLogger is not a
+/// consumer-constructible public type -- applications obtain it via the default
+/// logger or the "logger-impl"="spdlog" registry factory.
+
+#include "iceberg/logging/config.h"
+
+#ifdef ICEBERG_HAS_SPDLOG
+
+#  include <atomic>
+#  include <memory>
+
+#  include <spdlog/logger.h>
+
+#  include "iceberg/logging/log_level.h"
+#  include "iceberg/logging/logger.h"
+
+namespace iceberg::internal {
+
+/// \brief Logger backed by spdlog (synchronous only in v1).
+///
+/// Synchronous because spdlog::source_loc holds non-owning const char* that are
+/// unsafe to forward into an async logger (spdlog #3227).
+/// ICEBERG_EXPORT so the symbol is linkable from in-tree tests (and any
+/// internal consumer) under -fvisibility=hidden / MSVC DLL builds. The header
+/// is still not installed -- this is a binary-visibility detail, not public API.
+class ICEBERG_EXPORT SpdLogger : public Logger {
+ public:
+  /// \brief Construct over a default stderr-backed spdlog logger.
+  explicit SpdLogger(LogLevel level = LogLevel::kInfo);
+
+  /// \brief Construct over a caller-provided spdlog logger.
+  ///
+  /// The logger MUST be synchronous. Log() forwards spdlog::source_loc, which
+  /// borrows the std::source_location's const char* pointers; an async spdlog
+  /// logger would queue them past their lifetime (spdlog #3227 -> UB). This is a
+  /// caller contract -- spdlog exposes no reliable sync/async query to assert on.
+  explicit SpdLogger(std::shared_ptr<spdlog::logger> logger,
+                     LogLevel level = LogLevel::kInfo);
+
+  /// \brief Apply the "pattern" property (spdlog set_pattern), then "level".
+  Status Initialize(
+      const std::unordered_map<std::string, std::string>& properties) override;
+
+  bool ShouldLog(LogLevel level) const noexcept override {
+    return level >= level_.load(std::memory_order_relaxed);
+  }
+  void Log(LogMessage&& message) noexcept override;
+  void SetLevel(LogLevel level) noexcept override {
+    level_.store(level, std::memory_order_relaxed);
+  }
+  LogLevel level() const noexcept override {
+    return level_.load(std::memory_order_relaxed);
+  }
+  void Flush() noexcept override;
+
+ private:
+  std::shared_ptr<spdlog::logger> logger_;
+  std::atomic<LogLevel> level_;
+};
+
+}  // namespace iceberg::internal
+
+#endif  // ICEBERG_HAS_SPDLOG

src/iceberg/logging/logger.cc

@@ -26,7 +26,13 @@
 #include <tuple>
 #include <utility>
 
+// Build-generated, .cc-only (never from a public header). Defines
+// ICEBERG_HAS_SPDLOG when built with -DICEBERG_SPDLOG=ON; tested with #ifdef.
 #include "iceberg/logging/cerr_logger.h"
+#include "iceberg/logging/config.h"
+#ifdef ICEBERG_HAS_SPDLOG
+#  include "iceberg/logging/internal/spdlog_logger.h"
+#endif
 
 namespace iceberg {
 
@@ -44,9 +50,15 @@ class NoopLogger final : public Logger {
 
 /// \brief Construct the process default logger for this build configuration.
 ///
-/// Uses the always-available std::cerr sink. The spdlog backend (preferred when
-/// compiled in) is wired into this factory in a later block.
-std::shared_ptr<Logger> MakeDefaultLogger() { return std::make_shared<CerrLogger>(); }
+/// Prefers the spdlog backend when compiled in; otherwise the always-available
+/// std::cerr logger.
+std::shared_ptr<Logger> MakeDefaultLogger() {
+#ifdef ICEBERG_HAS_SPDLOG
+  return std::make_shared<internal::SpdLogger>();
+#else
+  return std::make_shared<CerrLogger>();
+#endif
+}
 
 /// \brief The process-global default-logger slot.
 struct DefaultSlot {

src/iceberg/logging/meson.build

@@ -15,6 +15,21 @@
 # specific language governing permissions and limitations
 # under the License.
 
+# Generate the .cc-only logging backend config header. ALWAYS generated (logger.cc
+# includes it in both configurations); only the definedness of ICEBERG_HAS_SPDLOG
+# varies with the `spdlog` feature option -- mirroring CMake's ICEBERG_SPDLOG. When
+# disabled, CerrLogger is the default sink and spdlog is neither compiled nor
+# linked. Generated into build/src/iceberg/logging/config.h (resolved via
+# include_directories('..'), which exposes both the source and build trees); not
+# installed.
+logging_config_data = configuration_data()
+if spdlog_enabled
+    logging_config_data.set('ICEBERG_HAS_SPDLOG', 1)
+endif
+configure_file(output: 'config.h', configuration: logging_config_data)
+
+# Public logging headers. The build-generated config.h and the internal
+# SpdLogger header are intentionally NOT installed.
 install_headers(
     [
         'cerr_logger.h',