feat: metrics reporting for scan and commit

src/iceberg/CMakeLists.txt

@@ -58,6 +58,7 @@ set(ICEBERG_SOURCES
     manifest/v3_metadata.cc
     metadata_columns.cc
     metrics_config.cc
+    metrics_reporters.cc
     name_mapping.cc
     partition_field.cc
     partition_spec.cc

src/iceberg/meson.build

@@ -76,6 +76,7 @@ iceberg_sources = files(
     'manifest/v3_metadata.cc',
     'metadata_columns.cc',
     'metrics_config.cc',
+    'metrics_reporters.cc',
     'name_mapping.cc',
     'partition_field.cc',
     'partition_spec.cc',

src/iceberg/metrics_reporter.h

@@ -0,0 +1,199 @@
+/*
+ * 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
+
+#include <chrono>
+#include <memory>
+#include <string>
+#include <string_view>
+#include <utility>
+#include <variant>
+
+#include "iceberg/iceberg_export.h"
+
+namespace iceberg {
+
+/// \brief Duration type for metrics reporting in milliseconds.
+using DurationMs = std::chrono::milliseconds;
+
+/// \brief Report generated after a table scan operation.
+///
+/// Contains metrics about the planning and execution of a table scan,
+/// including information about manifests and data files processed.
+struct ICEBERG_EXPORT ScanReport {
+  /// \brief The fully qualified name of the table that was scanned.
+  std::string table_name;
+
+  /// \brief Snapshot ID that was scanned, if available.
+  int64_t snapshot_id = -1;
+
+  /// \brief Filter expression used in the scan, if any.
+  std::string filter;
+
+  /// \brief Schema ID.
+  int32_t schema_id = -1;
+
+  /// \brief Total duration of the entire scan operation.
+  DurationMs total_duration{0};
+
+  /// \brief Duration spent planning the scan.
+  DurationMs total_planning_duration{0};
+
+  /// \brief Number of data files in the scan result.
+  int64_t result_data_files = 0;
+
+  /// \brief Number of delete files in the scan result.
+  int64_t result_delete_files = 0;
+
+  /// \brief Total number of data manifests.
+  int64_t total_data_manifests = 0;
+
+  /// \brief Number of data manifests that were skipped.
+  int64_t skipped_data_files = 0;
+
+  /// \brief Number of data manifests that were skipped.
+  int64_t skipped_delete_files = 0;
+
+  /// \brief Number of data manifests that were scanned.
+  int64_t scanned_data_manifests = 0;
+
+  /// \brief Number of data manifests that were skipped due to filtering.
+  int64_t skipped_data_manifests = 0;
+
+  /// \brief Total number of delete manifests.
+  int64_t total_delete_manifests = 0;
+
+  /// \brief Number of delete manifests that were scanned.
+  int64_t scanned_delete_manifests = 0;
+
+  /// \brief Number of delete manifests that were skipped.
+  int64_t skipped_delete_manifests = 0;
+};
+
+/// \brief Report generated after a commit operation.
+///
+/// Contains metrics about the changes made in a commit, including
+/// files added/removed and retry information.
+struct ICEBERG_EXPORT CommitReport {
+  /// \brief The fully qualified name of the table that was modified.
+  std::string table_name;
+
+  /// \brief The snapshot ID created by this commit.
+  int64_t snapshot_id = -1;
+
+  /// \brief The sequence number assigned to this commit.
+  int64_t sequence_number = -1;
+
+  /// \brief The operation that was performed (append, overwrite, delete, etc.).
+  std::string operation;
+
+  /// \brief Number of commit attempts (1 = success on first try).
+  int32_t attempts = 1;
+
+  /// \brief Number of data files added in this commit.
+  int64_t added_data_files = 0;
+
+  /// \brief Number of data files removed in this commit.
+  int64_t removed_data_files = 0;
+
+  /// \brief Total number of data files after this commit.
+  int64_t total_data_files = 0;
+
+  /// \brief Number of delete files added in this commit.
+  int64_t added_delete_files = 0;
+
+  /// \brief Number of delete files removed in this commit.
+  int64_t removed_delete_files = 0;
+
+  /// \brief Total number of delete files after this commit.
+  int64_t total_delete_files = 0;
+
+  /// \brief Number of records added in this commit.
+  int64_t added_records = 0;
+
+  /// \brief Number of records removed in this commit.
+  int64_t removed_records = 0;
+
+  /// \brief Size in bytes of files added.
+  int64_t added_files_size = 0;
+
+  /// \brief Size in bytes of files removed.
+  int64_t removed_files_size = 0;
+};
+
+/// \brief The type of a metrics report.
+enum class MetricsReportType {
+  kScanReport,
+  kCommitReport,
+};
+
+/// \brief Get the string representation of a metrics report type.
+ICEBERG_EXPORT constexpr std::string_view ToString(MetricsReportType type) noexcept {
+  switch (type) {
+    case MetricsReportType::kScanReport:
+      return "scan";
+    case MetricsReportType::kCommitReport:
+      return "commit";
+  }
+  std::unreachable();
+}
+
+/// \brief A metrics report, which can be either a ScanReport or CommitReport.
+///
+/// This variant type allows handling both report types uniformly through
+/// the MetricsReporter interface.
+using MetricsReport = std::variant<ScanReport, CommitReport>;
+
+/// \brief Get the type of a metrics report.
+///
+/// \param report The metrics report to get the type of.
+/// \return The type of the metrics report.
+ICEBERG_EXPORT inline MetricsReportType GetReportType(const MetricsReport& report) {
+  return std::visit(
+      [](const auto& r) -> MetricsReportType {
+        using T = std::decay_t<decltype(r)>;
+        if constexpr (std::is_same_v<T, ScanReport>) {
+          return MetricsReportType::kScanReport;
+        } else {
+          return MetricsReportType::kCommitReport;
+        }
+      },
+      report);
+}
+
+/// \brief Interface for reporting metrics from Iceberg operations.
+///
+/// Implementations of this interface can be used to collect and report
+/// metrics about scan and commit operations. Common implementations include
+/// logging reporters, metrics collectors, and the noop reporter for testing.
+class ICEBERG_EXPORT MetricsReporter {
+ public:
+  virtual ~MetricsReporter() = default;
+
+  /// \brief Report a metrics report.
+  ///
+  /// Implementations should handle the report according to their purpose
+  /// (e.g., logging, sending to a metrics service, etc.).
+  ///
+  /// \param report The metrics report to process.
+  virtual void Report(const MetricsReport& report) = 0;
+};
+
+}  // namespace iceberg

src/iceberg/metrics_reporters.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/metrics_reporters.h"
+
+#include <unordered_set>
+
+#include "iceberg/util/string_util.h"
+
+namespace iceberg {
+
+namespace {
+
+/// \brief Registry type for MetricsReporter factories with heterogeneous lookup support.
+using MetricsReporterRegistry = std::unordered_map<std::string, MetricsReporterFactory>;
+
+/// \brief Get the set of known metrics reporter types.
+const std::unordered_set<std::string>& DefaultReporterTypes() {
+  static const std::unordered_set<std::string> kReporterTypes = {
+      std::string(kMetricsReporterTypeNoop),
+  };
+  return kReporterTypes;
+}
+
+/// \brief Infer the reporter type from properties.
+std::string InferReporterType(
+    const std::unordered_map<std::string, std::string>& properties) {
+  auto it = properties.find(std::string(kMetricsReporterType));
+  if (it != properties.end() && !it->second.empty()) {
+    return StringUtils::ToLower(it->second);
+  }
+  // Default to noop reporter
+  return std::string(kMetricsReporterTypeNoop);
+}
+
+/// \brief Metrics reporter that does nothing.
+///
+/// This is the default reporter used when no reporter is configured.
+/// It silently discards all reports.
+class NoopMetricsReporter : public MetricsReporter {
+ public:
+  static Result<std::unique_ptr<MetricsReporter>> Make(
+      [[maybe_unused]] std::string_view name,
+      [[maybe_unused]] const std::unordered_map<std::string, std::string>& properties) {
+    return std::make_unique<NoopMetricsReporter>();
+  }
+
+  void Report([[maybe_unused]] const MetricsReport& report) override {
+    // Intentionally empty - noop implementation discards all reports
+  }
+};
+
+/// \brief Template helper to create factory functions for reporter types.
+template <typename T>
+MetricsReporterFactory MakeReporterFactory() {
+  return
+      [](std::string_view name, const std::unordered_map<std::string, std::string>& props)
+          -> Result<std::unique_ptr<MetricsReporter>> { return T::Make(name, props); };
+}
+
+/// \brief Create the default registry with built-in reporters.
+MetricsReporterRegistry CreateDefaultRegistry() {
+  return {
+      {std::string(kMetricsReporterTypeNoop), MakeReporterFactory<NoopMetricsReporter>()},
+  };
+}
+
+/// \brief Get the global registry of metrics reporter factories.
+MetricsReporterRegistry& GetRegistry() {
+  static MetricsReporterRegistry registry = CreateDefaultRegistry();
+  return registry;
+}
+
+}  // namespace
+
+void MetricsReporters::Register(std::string_view reporter_type,
+                                MetricsReporterFactory factory) {
+  GetRegistry()[StringUtils::ToLower(reporter_type)] = std::move(factory);
+}
+
+Result<std::unique_ptr<MetricsReporter>> MetricsReporters::Load(
+    std::string_view name,
+    const std::unordered_map<std::string, std::string>& properties) {
+  std::string reporter_type = InferReporterType(properties);
+
+  auto& registry = GetRegistry();
+  auto it = registry.find(reporter_type);
+  if (it == registry.end()) {
+    if (DefaultReporterTypes().contains(reporter_type)) {
+      return NotImplemented("Metrics reporter type '{}' is not yet supported",
+                            reporter_type);
+    }
+    return InvalidArgument("Unknown metrics reporter type: '{}'", reporter_type);
+  }
+
+  return it->second(name, properties);
+}
+
+}  // namespace iceberg