Validate configuration file against JSON schema

.clangd

@@ -4,3 +4,6 @@
 ---
 Diagnostics:
   UnusedIncludes: Strict
+
+CompileFlags:
+  CompilationDatabase: build

.editorconfig

@@ -26,7 +26,7 @@ indent_size = 4
 indent_style = space
 indent_size = 4
 
-[*.{nix,json}]
+[*.{nix,json,yaml}]
 indent_style = space
 indent_size = 2
 

.gdbinit

@@ -0,0 +1,12 @@
+# SPDX-FileCopyrightText: 2026 Institute for Automation of Complex Power Systems, RWTH Aachen University
+# SPDX-License-Identifier: Apache-2.0
+# Author: Philipp Jungkamp <philipp.jungkamp@rwth-aachen.de>
+
+python
+
+import os
+import gdb
+
+if nlohmann_json_src := os.environ.get('NLOHMANN_JSON_SRC'):
+    gdb.execute(f"source {nlohmann_json_src}/tools/gdb_pretty_printer/nlohmann-json.py")
+end

.pre-commit-config.yaml

@@ -26,7 +26,7 @@ repos:
         exclude: .devcontainer/devcontainer\.json
       - id: check-toml
       - id: check-added-large-files
-        exclude: ^paper\.md$
+        exclude: ^(?:paper\.md|lib/json_schema\.cpp)$
       - id: pretty-format-json
         # black has its own mind of formatting Jupyter notebooks
         exclude: \.ipynb$|^.devcontainer/devcontainer\.json$|package-lock\.json$

CMakeLists.txt

@@ -81,6 +81,7 @@ find_package(PkgConfig REQUIRED)
 find_package(spdlog REQUIRED)
 find_package(Threads REQUIRED)
 find_package(nlohmann_json REQUIRED)
+find_package(nlohmann_json_schema_validator REQUIRED)
 find_package(OpenMP)
 find_package(IBVerbs)
 find_package(RDMACM)

common/include/villas/exceptions.hpp

@@ -43,22 +43,6 @@ class MemoryAllocationError : public RuntimeError {
   MemoryAllocationError() : RuntimeError("Failed to allocate memory") {}
 };
 
-class JsonError : public std::runtime_error {
-
-protected:
-  json_error_t error;
-
-public:
-  template <typename... Args>
-  JsonError(const json_t *s, const json_error_t &e,
-            const std::string &what = std::string(), Args &&...args)
-      : std::runtime_error(
-            fmt::format("{}: {} in {}:{}:{}",
-                        fmt::format(what, std::forward<Args>(args)...),
-                        error.text, error.source, error.line, error.column)),
-        error(e) {}
-};
-
 class ConfigError : public std::runtime_error {
 
 protected:

common/include/villas/jansson.hpp

@@ -43,21 +43,20 @@ class JanssonPtr {
 
   ::json_t *release() { return std::exchange(inner, nullptr); }
 
-  void reset() {
-    json_decref(inner);
-    inner = nullptr;
-  }
-
-  void reset(::json_t *json) {
+  void reset(::json_t *json = nullptr) {
     json_decref(inner);
     inner = json_incref(json);
   }
 
   void swap(JanssonPtr &other) { std::swap(inner, other.inner); }
 
   operator bool() { return inner != nullptr; }
-  ::json_t *get() const { return inner; }
-  ::json_t *operator->() const { return inner; }
+
+  ::json_t const *get() const { return inner; }
+  ::json_t *get() { return inner; }
+
+  ::json_t const *operator->() const { return inner; }
+  ::json_t *operator->() { return inner; }
 
   friend void swap(JanssonPtr &lhs, JanssonPtr &rhs) { lhs.swap(rhs); }
   friend auto operator<=>(JanssonPtr const &, JanssonPtr const &) = default;

common/include/villas/json.hpp

@@ -27,6 +27,7 @@ struct LoadConfigFileOptions {
   bool allow_libconfig = false;
   bool allow_environment = false;
   bool allow_include = false;
+  bool allow_comments = false;
 };
 
 // load a configuration file

common/lib/json.cpp

@@ -150,7 +150,7 @@ void to_json(Json &json, JanssonPtr const &jansson) {
 namespace {
 
 // Implement the deprecated variable substitution syntax.
-void expand_substitutions(Json &value, bool resolve_env,
+void expand_substitutions(Json &value, bool resolve_env, bool allow_comments,
                           fs::path const *include_dir) {
   if (not value.is_string())
     return;
@@ -204,6 +204,7 @@ void expand_substitutions(Json &value, bool resolve_env,
                                      .allow_libconfig = false,
                                      .allow_environment = resolve_env,
                                      .allow_include = include_dir != nullptr,
+                                     .allow_comments = allow_comments,
                                  });
       if (result.is_null())
         result = partial_result;
@@ -225,14 +226,16 @@ void expand_substitutions(Json &value, bool resolve_env,
 #ifdef WITH_CONFIG
 
 Json parse_libconfig_setting(::config_setting_t const *setting,
-                             bool resolve_env, fs::path const *include_dir) {
+                             bool resolve_env, bool allow_comments,
+                             fs::path const *include_dir) {
   switch (config_setting_type(setting)) {
   case CONFIG_TYPE_ARRAY:
   case CONFIG_TYPE_LIST: {
     auto array = Json::array();
     for (auto const idx : std::views::iota(0, config_setting_length(setting))) {
       auto const elem = config_setting_get_elem(setting, idx);
-      array.push_back(parse_libconfig_setting(elem, resolve_env, include_dir));
+      array.push_back(parse_libconfig_setting(elem, resolve_env, allow_comments,
+                                              include_dir));
     }
 
     return array;
@@ -244,15 +247,16 @@ Json parse_libconfig_setting(::config_setting_t const *setting,
       auto const elem = config_setting_get_elem(setting, idx);
       auto name = std::string(config_setting_name(elem));
       object.emplace(std::move(name),
-                     parse_libconfig_setting(elem, resolve_env, include_dir));
+                     parse_libconfig_setting(elem, resolve_env, allow_comments,
+                                             include_dir));
     }
 
     return object;
   }
 
   case CONFIG_TYPE_STRING: {
     auto json = Json(std::string(config_setting_get_string(setting)));
-    expand_substitutions(json, resolve_env, include_dir);
+    expand_substitutions(json, resolve_env, allow_comments, include_dir);
     return json;
   }
 
@@ -299,7 +303,8 @@ extern "C" char const **libconfig_include_func(::config_t *config, char const *,
   }
 
   auto pattern_json = Json(pattern);
-  expand_substitutions(pattern_json, hook->resolve_env, nullptr);
+  // The null include_dir only expands environment variables in the pattern.
+  expand_substitutions(pattern_json, hook->resolve_env, false, nullptr);
   auto const &pattern_expanded = pattern_json.get_ref<std::string const &>();
 
   try {
@@ -327,7 +332,7 @@ extern "C" char const **libconfig_include_func(::config_t *config, char const *,
 
 #endif
 
-Json load_libconfig_file(std::FILE *file, bool resolve_env,
+Json load_libconfig_file(std::FILE *file, bool resolve_env, bool allow_comments,
                          fs::path const *include_dir) {
   using ConfigDestroy = decltype([](::config_t *c) { ::config_destroy(c); });
   using ConfigGuard = std::unique_ptr<::config_t, ConfigDestroy>;
@@ -359,7 +364,7 @@ Json load_libconfig_file(std::FILE *file, bool resolve_env,
   }
 
   return parse_libconfig_setting(config_root_setting(&config), resolve_env,
-                                 include_dir);
+                                 allow_comments, include_dir);
 }
 
 #endif // WITH_CONFIG
@@ -381,16 +386,17 @@ Json load_config_file(fs::path const &path, LoadConfigFileOptions const &opts) {
     auto parser_callback = [&](int depth, Json::parse_event_t event,
                                Json &value) {
       if (event == Json::parse_event_t::value)
-        expand_substitutions(value, opts.allow_environment,
+        expand_substitutions(value, opts.allow_environment, opts.allow_comments,
                              opts.allow_include ? &include_dir : nullptr);
 
       return true;
     };
 
-    return Json::parse(file.get(), parser_callback);
+    return Json::parse(file.get(), parser_callback, true, opts.allow_comments);
   } else if (opts.allow_libconfig) {
 #ifdef WITH_CONFIG
     return load_libconfig_file(file.get(), opts.allow_environment,
+                               opts.allow_comments,
                                opts.allow_include ? &include_dir : nullptr);
 #else
     throw std::runtime_error(

common/lib/tool.cpp

@@ -60,7 +60,7 @@ int Tool::run() {
     logger->info(CLR_GRN("Goodbye!"));
 
     return ret;
-  } catch (const std::runtime_error &e) {
+  } catch (const std::exception &e) {
     logger->error("{}", e.what());
 
     return -1;

doc/openapi/components/schemas/config/http.yaml → doc/openapi/components/schemas/config-http.yaml

@@ -4,6 +4,13 @@
 ---
 type: object
 properties:
+  enabled:
+    type: boolean
+    default: true
+    title: Enable HTTP server
+    description: |
+      When set to `false`, the built-in HTTP & WebSocket server is disabled and will not listen on any port.
+
   port:
     type: integer
     default: 80
@@ -26,3 +33,5 @@ properties:
       The private x509 key used for server-side SSL encryption.
 
     example: /etc/ssl/private/mykey.pem
+
+additionalProperties: false

doc/openapi/components/schemas/config/logging.yaml → doc/openapi/components/schemas/config-logging.yaml

@@ -5,7 +5,6 @@
 type: object
 title: Logging configuration
 properties:
-
   level:
     title: The log level
     description: |
@@ -69,3 +68,6 @@ properties:
             - error
             - critical
             - 'off'
+      additionalProperties: false
+
+additionalProperties: false