[CONFIGURATION] File configuration - yaml parser

sdk/include/opentelemetry/sdk/configuration/configuration.h

@@ -34,6 +34,15 @@
  *   Yaml node OpenTelemetryConfiguration,
  * in file
  * https://github.com/open-telemetry/opentelemetry-configuration/blob/main/schema/opentelemetry_configuration.json
+ *
+ * Every property in the yaml schema is already documented in the
+ * opentelemetry-configuration repository,
+ * in file schema/type_descriptions.yaml, see
+ * https://github.com/open-telemetry/opentelemetry-configuration/blob/main/schema/type_descriptions.yaml
+ *
+ * As a result, C++ class members representing yaml properties are not
+ * commented with details, refer to the source of truth in
+ * type_descriptions.yaml directly.
  */
 
 OPENTELEMETRY_BEGIN_NAMESPACE

sdk/include/opentelemetry/sdk/configuration/configuration_parser.h

@@ -0,0 +1,26 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <memory>
+
+#include "opentelemetry/sdk/configuration/configuration.h"
+#include "opentelemetry/sdk/configuration/document_node.h"
+#include "opentelemetry/version.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace sdk
+{
+namespace configuration
+{
+
+class ConfigurationParser
+{
+public:
+  static std::unique_ptr<Configuration> Parse(std::unique_ptr<Document> doc);
+};
+
+}  // namespace configuration
+}  // namespace sdk
+OPENTELEMETRY_END_NAMESPACE

sdk/include/opentelemetry/sdk/configuration/document.h

@@ -0,0 +1,33 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <memory>
+#include <string>
+
+#include "opentelemetry/sdk/configuration/document_node.h"
+#include "opentelemetry/version.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace sdk
+{
+namespace configuration
+{
+
+class Document
+{
+public:
+  Document()                                 = default;
+  Document(Document &&)                      = default;
+  Document(const Document &)                 = default;
+  Document &operator=(Document &&)           = default;
+  Document &operator=(const Document &other) = default;
+  virtual ~Document()                        = default;
+
+  virtual std::unique_ptr<DocumentNode> GetRootNode() = 0;
+};
+
+}  // namespace configuration
+}  // namespace sdk
+OPENTELEMETRY_END_NAMESPACE

sdk/include/opentelemetry/sdk/configuration/document_node.h

@@ -0,0 +1,176 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <memory>
+#include <string>
+
+#include "opentelemetry/version.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace sdk
+{
+namespace configuration
+{
+
+class DocumentNodeConstIterator;
+class PropertiesNodeConstIterator;
+
+class DocumentNode
+{
+public:
+  // FIXME: proper sizing
+  static constexpr std::size_t MAX_NODE_DEPTH = 100;
+
+  DocumentNode()                                     = default;
+  DocumentNode(DocumentNode &&)                      = default;
+  DocumentNode(const DocumentNode &)                 = default;
+  DocumentNode &operator=(DocumentNode &&)           = default;
+  DocumentNode &operator=(const DocumentNode &other) = default;
+  virtual ~DocumentNode()                            = default;
+
+  virtual std::string Key() const = 0;
+
+  virtual bool AsBoolean()        = 0;
+  virtual std::size_t AsInteger() = 0;
+  virtual double AsDouble()       = 0;
+  virtual std::string AsString()  = 0;
+
+  virtual std::unique_ptr<DocumentNode> GetRequiredChildNode(const std::string &name) = 0;
+  virtual std::unique_ptr<DocumentNode> GetChildNode(const std::string &name)         = 0;
+
+  virtual bool GetRequiredBoolean(const std::string &name)             = 0;
+  virtual bool GetBoolean(const std::string &name, bool default_value) = 0;
+
+  virtual std::size_t GetRequiredInteger(const std::string &name)                    = 0;
+  virtual std::size_t GetInteger(const std::string &name, std::size_t default_value) = 0;
+
+  virtual double GetRequiredDouble(const std::string &name)               = 0;
+  virtual double GetDouble(const std::string &name, double default_value) = 0;
+
+  virtual std::string GetRequiredString(const std::string &name)                           = 0;
+  virtual std::string GetString(const std::string &name, const std::string &default_value) = 0;
+
+  virtual DocumentNodeConstIterator begin() const = 0;
+  virtual DocumentNodeConstIterator end() const   = 0;
+
+  virtual std::size_t num_children() const                                = 0;
+  virtual std::unique_ptr<DocumentNode> GetChild(std::size_t index) const = 0;
+
+  virtual PropertiesNodeConstIterator begin_properties() const = 0;
+  virtual PropertiesNodeConstIterator end_properties() const   = 0;
+
+protected:
+  std::string DoSubstitution(const std::string &text);
+  std::string DoOneSubstitution(const std::string &text);
+
+  bool BooleanFromString(const std::string &value);
+  std::size_t IntegerFromString(const std::string &value);
+  double DoubleFromString(const std::string &value);
+};
+
+class DocumentNodeConstIteratorImpl
+{
+public:
+  DocumentNodeConstIteratorImpl()                                                      = default;
+  DocumentNodeConstIteratorImpl(DocumentNodeConstIteratorImpl &&)                      = default;
+  DocumentNodeConstIteratorImpl(const DocumentNodeConstIteratorImpl &)                 = default;
+  DocumentNodeConstIteratorImpl &operator=(DocumentNodeConstIteratorImpl &&)           = default;
+  DocumentNodeConstIteratorImpl &operator=(const DocumentNodeConstIteratorImpl &other) = default;
+  virtual ~DocumentNodeConstIteratorImpl()                                             = default;
+
+  virtual void Next()                                                = 0;
+  virtual std::unique_ptr<DocumentNode> Item() const                 = 0;
+  virtual bool Equal(const DocumentNodeConstIteratorImpl *rhs) const = 0;
+};
+
+class PropertiesNodeConstIteratorImpl
+{
+public:
+  PropertiesNodeConstIteratorImpl()                                              = default;
+  PropertiesNodeConstIteratorImpl(PropertiesNodeConstIteratorImpl &&)            = default;
+  PropertiesNodeConstIteratorImpl(const PropertiesNodeConstIteratorImpl &)       = default;
+  PropertiesNodeConstIteratorImpl &operator=(PropertiesNodeConstIteratorImpl &&) = default;
+  PropertiesNodeConstIteratorImpl &operator=(const PropertiesNodeConstIteratorImpl &other) =
+      default;
+  virtual ~PropertiesNodeConstIteratorImpl() = default;
+
+  virtual void Next()                                                  = 0;
+  virtual std::string Name() const                                     = 0;
+  virtual std::unique_ptr<DocumentNode> Value() const                  = 0;
+  virtual bool Equal(const PropertiesNodeConstIteratorImpl *rhs) const = 0;
+};
+
+class DocumentNodeConstIterator
+{
+public:
+  DocumentNodeConstIterator(std::unique_ptr<DocumentNodeConstIteratorImpl> impl)
+      : impl_(std::move(impl))
+  {}
+  DocumentNodeConstIterator(DocumentNodeConstIterator &&)                      = default;
+  DocumentNodeConstIterator(const DocumentNodeConstIterator &)                 = delete;
+  DocumentNodeConstIterator &operator=(DocumentNodeConstIterator &&)           = default;
+  DocumentNodeConstIterator &operator=(const DocumentNodeConstIterator &other) = delete;
+  ~DocumentNodeConstIterator()                                                 = default;
+
+  bool operator==(const DocumentNodeConstIterator &rhs) const
+  {
+    return (impl_->Equal(rhs.impl_.get()));
+  }
+
+  bool operator!=(const DocumentNodeConstIterator &rhs) const
+  {
+    return (!impl_->Equal(rhs.impl_.get()));
+  }
+
+  std::unique_ptr<DocumentNode> operator*() const { return impl_->Item(); }
+
+  DocumentNodeConstIterator &operator++()
+  {
+    impl_->Next();
+    return *this;
+  }
+
+private:
+  std::unique_ptr<DocumentNodeConstIteratorImpl> impl_;
+};
+
+class PropertiesNodeConstIterator
+{
+public:
+  PropertiesNodeConstIterator(std::unique_ptr<PropertiesNodeConstIteratorImpl> impl)
+      : impl_(std::move(impl))
+  {}
+  PropertiesNodeConstIterator(PropertiesNodeConstIterator &&)                      = default;
+  PropertiesNodeConstIterator(const PropertiesNodeConstIterator &)                 = delete;
+  PropertiesNodeConstIterator &operator=(PropertiesNodeConstIterator &&)           = default;
+  PropertiesNodeConstIterator &operator=(const PropertiesNodeConstIterator &other) = delete;
+  ~PropertiesNodeConstIterator()                                                   = default;
+
+  bool operator==(const PropertiesNodeConstIterator &rhs) const
+  {
+    return (impl_->Equal(rhs.impl_.get()));
+  }
+
+  bool operator!=(const PropertiesNodeConstIterator &rhs) const
+  {
+    return (!impl_->Equal(rhs.impl_.get()));
+  }
+
+  std::string Name() const { return impl_->Name(); }
+  std::unique_ptr<DocumentNode> Value() const { return impl_->Value(); }
+
+  PropertiesNodeConstIterator &operator++()
+  {
+    impl_->Next();
+    return *this;
+  }
+
+private:
+  std::unique_ptr<PropertiesNodeConstIteratorImpl> impl_;
+};
+
+}  // namespace configuration
+}  // namespace sdk
+OPENTELEMETRY_END_NAMESPACE

sdk/include/opentelemetry/sdk/configuration/invalid_schema_exception.h

@@ -0,0 +1,27 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <stdexcept>
+#include <string>
+
+#include "opentelemetry/sdk/configuration/document.h"
+#include "opentelemetry/sdk/configuration/document_node.h"
+#include "opentelemetry/version.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace sdk
+{
+namespace configuration
+{
+
+class InvalidSchemaException : public std::runtime_error
+{
+public:
+  InvalidSchemaException(const std::string &msg) : std::runtime_error(msg) {}
+};
+
+}  // namespace configuration
+}  // namespace sdk
+OPENTELEMETRY_END_NAMESPACE

sdk/include/opentelemetry/sdk/configuration/ryml_document.h

@@ -0,0 +1,40 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <memory>
+#include <ryml.hpp>
+#include <string>
+
+#include "opentelemetry/sdk/configuration/document.h"
+#include "opentelemetry/sdk/configuration/document_node.h"
+#include "opentelemetry/version.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace sdk
+{
+namespace configuration
+{
+
+class RymlDocument : public Document
+{
+public:
+  static std::unique_ptr<Document> Parse(const std::string &source, const std::string &content);
+
+  RymlDocument(ryml::Tree tree) : tree_(std::move(tree)) {}
+  RymlDocument(RymlDocument &&)                      = delete;
+  RymlDocument(const RymlDocument &)                 = delete;
+  RymlDocument &operator=(RymlDocument &&)           = delete;
+  RymlDocument &operator=(const RymlDocument &other) = delete;
+  ~RymlDocument() override                           = default;
+
+  std::unique_ptr<DocumentNode> GetRootNode() override;
+
+private:
+  ryml::Tree tree_;
+};
+
+}  // namespace configuration
+}  // namespace sdk
+OPENTELEMETRY_END_NAMESPACE