add crate_config_from_file() and use it in the mini-daq to load both JSON or YAML

Author: flueke

extras/mini-daq/src/mini_daq_main.cc

@@ -328,7 +328,7 @@ int main(int argc, char *argv[])
 
         // positional args
         | lyra::arg(opt_crateConfig, "crateConfig")
-            ("crate config yaml file").required()
+            ("crate config YAML or JSON file").required()
 
         | lyra::arg(opt_secondsToRun, "secondsToRun")
             ("duration the DAQ should run in seconds").optional()
@@ -365,15 +365,6 @@ int main(int argc, char *argv[])
     if (opt_logTrace)
         set_global_log_level(spdlog::level::trace);
 
-
-    std::ifstream inConfig(opt_crateConfig);
-
-    if (!inConfig.is_open())
-    {
-        cerr << "Error opening crate config " << argv[1] << " for reading." << endl;
-        return 1;
-    }
-
     try
     {
         auto timeToRun = std::chrono::seconds(opt_secondsToRun);
@@ -382,11 +373,11 @@ int main(int argc, char *argv[])
 
         try
         {
-            crateConfig = crate_config_from_yaml(inConfig);
+            crateConfig = crate_config_from_file(opt_crateConfig);
         }
         catch (const std::runtime_error &e)
         {
-            cerr << "Error parsing CrateConfig: " << e.what() << endl;
+            cerr << fmt::format("Error loading CrateConfig from '{}': {}\n", opt_crateConfig, e.what());
             return 1;
         }
 

src/mesytec-mvlc/mvlc_readout_config.cc

@@ -2,6 +2,7 @@
 
 #include <cassert>
 #include <fstream>
+#include <nlohmann/json.hpp>
 
 #include "util/fmt.h"
 #include "util/string_util.h"
@@ -331,6 +332,39 @@ StackCommandBuilder stack_command_builder_from_yaml_file(
     return stack_command_builder_from_yaml(input);
 }
 
+CrateConfig crate_config_from_data(const std::string &data, const std::string &format_)
+{
+    auto format = util::str_tolower(format_);
+
+    if (format == "yaml")
+        return crate_config_from_yaml(data);
+
+    if (format == "json")
+        return crate_config_from_json(data);
+
+    throw std::runtime_error(fmt::format("unexpected format '{}', want 'json' or 'yaml'.", format));
+}
+
+CrateConfig crate_config_from_file(const std::string &filename)
+{
+    std::filesystem::path fp(filename);
+
+    if (fp.extension() == ".json")
+    {
+        std::ifstream input(filename);
+        input.exceptions(std::ios::failbit | std::ios::badbit);
+        auto json = nlohmann::json::parse(input);
+        return crate_config_from_json(json.dump());
+    }
+    else if (fp.extension() == ".yaml")
+    {
+        return crate_config_from_yaml_file(filename);
+    }
+
+    throw std::runtime_error(fmt::format("unexpected file extension '{}', want '.json' or '.yaml'.",
+         fp.extension().string()));
+}
+
 namespace detail
 {
 template<typename T>

src/mesytec-mvlc/mvlc_readout_config.h

@@ -75,6 +75,14 @@ StackCommandBuilder MESYTEC_MVLC_EXPORT stack_command_builder_from_yaml_file(con
 std::string MESYTEC_MVLC_EXPORT to_json(const CrateConfig &crateConfig);
 CrateConfig MESYTEC_MVLC_EXPORT crate_config_from_json(const std::string &json);
 
+// Wrapper around the from_yaml/from_json functions.
+// - data contains the raw YAML or JSON data.
+// - format is either "yaml" or "json".
+// Throws on error
+CrateConfig MESYTEC_MVLC_EXPORT crate_config_from_data(const std::string &data, const std::string &format);
+CrateConfig MESYTEC_MVLC_EXPORT crate_config_from_file(const std::string &filename);
+
+// StackCommandBuilder serialization
 std::string MESYTEC_MVLC_EXPORT to_json(const StackCommandBuilder &sb);
 StackCommandBuilder MESYTEC_MVLC_EXPORT stack_command_builder_from_json(const std::string &json);