add prompt dir app option

tooling/pipeline/src/data_generation/llama/generate_brewery.cc

@@ -59,11 +59,12 @@ BreweryResult LlamaGenerator::GenerateBrewery(
       location.country.empty() ? std::string{}
                                : std::format(", {}", location.country);
   /**
-   * Load brewery system prompt from file
-   * Falls back to minimal inline prompt if file not found
+   * Load brewery system prompt via the injected prompt directory.
+   * The key "BREWERY_GENERATION" resolves to BREWERY_GENERATION.md inside
+   * the configured --prompt-dir.  Throws on missing or empty file.
    */
   const std::string system_prompt =
-      LoadBrewerySystemPrompt("prompts/system.md");
+      prompt_directory_->Load("BREWERY_GENERATION");
 
   std::string user_prompt = std::format(
       "## CITY:\n{}\n\n## COUNTRY:\n{}\n\n## LOCAL LANGUAGE CODES:\n{}\n\n## "

tooling/pipeline/src/data_generation/llama/llama_generator.cc

@@ -32,9 +32,11 @@ void LlamaGenerator::ContextDeleter::operator()(
 
 LlamaGenerator::LlamaGenerator(
     const ApplicationOptions& options, const std::string& model_path,
-    std::unique_ptr<IPromptFormatter> prompt_formatter)
+    std::unique_ptr<IPromptFormatter> prompt_formatter,
+    std::unique_ptr<IPromptDirectory> prompt_directory)
     : rng_(std::random_device{}()),
-      prompt_formatter_(std::move(prompt_formatter)) {
+      prompt_formatter_(std::move(prompt_formatter)),
+      prompt_directory_(std::move(prompt_directory)) {
   if (model_path.empty()) {
     throw std::runtime_error("LlamaGenerator: model path must not be empty");
   }
@@ -44,6 +46,11 @@ LlamaGenerator::LlamaGenerator(
         "LlamaGenerator: prompt formatter dependency must not be null");
   }
 
+  if (!prompt_directory_) {
+    throw std::runtime_error(
+        "LlamaGenerator: prompt directory dependency must not be null");
+  }
+
   const auto sampling = options.generator.sampling.value_or(SamplingOptions{});
 
   if (sampling.temperature < 0.0F) {

tooling/pipeline/src/data_generation/llama/load_brewery_prompt.cc

@@ -1,55 +0,0 @@
-/**
- * @file data_generation/llama/load_brewery_prompt.cc
- * @brief Resolves brewery system prompt content from cache or a configured
- * filesystem path and provides a robust inline fallback prompt when absent.
- */
-
-#include <spdlog/spdlog.h>
-
-#include <filesystem>
-#include <fstream>
-#include <stdexcept>
-
-#include "data_generation/llama_generator.h"
-
-/**
- * @brief Loads brewery system prompt from disk or cache.
- *
- * @param prompt_file_path Preferred prompt file location.
- * @return Prompt text loaded from disk.
- */
-std::string LlamaGenerator::LoadBrewerySystemPrompt(
-    const std::filesystem::path& prompt_file_path) {
-  // Return cached version if already loaded
-  if (!brewery_system_prompt_.empty()) {
-    return brewery_system_prompt_;
-  }
-
-  std::ifstream prompt_file(prompt_file_path);
-  if (!prompt_file.is_open()) {
-    spdlog::error(
-        "LlamaGenerator: Failed to open brewery system prompt file '{}'",
-        prompt_file_path.string());
-    throw std::runtime_error(
-        "LlamaGenerator: missing brewery system prompt file: " +
-        prompt_file_path.string());
-  }
-
-  const std::string prompt((std::istreambuf_iterator(prompt_file)),
-                           std::istreambuf_iterator<char>());
-  prompt_file.close();
-
-  if (prompt.empty()) {
-    spdlog::error("LlamaGenerator: Brewery system prompt file '{}' is empty",
-                  prompt_file_path.string());
-    throw std::runtime_error(
-        "LlamaGenerator: empty brewery system prompt file: " +
-        prompt_file_path.string());
-  }
-
-  spdlog::info(
-      "LlamaGenerator: Loaded brewery system prompt from '{}' ({} chars)",
-      prompt_file_path.string(), prompt.length());
-  brewery_system_prompt_ = prompt;
-  return brewery_system_prompt_;
-}

tooling/pipeline/src/main.cc

@@ -24,6 +24,7 @@
 #include "llama_backend_state.h"
 #include "services/enrichment_service.h"
 #include "services/export_service.h"
+#include "services/prompt_directory.h"
 #include "services/sqlite_export_service.h"
 #include "services/wikipedia_service.h"
 #include "web_client/curl_web_client.h"
@@ -70,6 +71,9 @@ std::optional<ApplicationOptions> ParseArguments(const int argc, char** argv) {
   opt("log-path",
       prog_opts::value<std::string>()->default_value("pipeline.log"),
       "Path for application logs");
+  opt("prompt-dir", prog_opts::value<std::string>()->default_value(""),
+      "Directory containing named prompt files (e.g. BREWERY_GENERATION.md)."
+      " Required when not using --mocked.");
 
   if (argc == 1) {
     spdlog::info("Biergarten Pipeline");
@@ -95,6 +99,7 @@ std::optional<ApplicationOptions> ParseArguments(const int argc, char** argv) {
 
     options.pipeline.output_path = vm["output"].as<std::string>();
     options.pipeline.log_path = vm["log-path"].as<std::string>();
+    options.pipeline.prompt_dir = vm["prompt-dir"].as<std::string>();
 
     const bool use_mocked = vm["mocked"].as<bool>();
     const std::string model_path = vm["model"].as<std::string>();
@@ -111,6 +116,13 @@ std::optional<ApplicationOptions> ParseArguments(const int argc, char** argv) {
       return std::nullopt;
     }
 
+    if (!use_mocked && options.pipeline.prompt_dir.empty()) {
+      spdlog::error(
+          "Invalid arguments: --prompt-dir is required when not using "
+          "--mocked");
+      return std::nullopt;
+    }
+
     options.generator.use_mocked = use_mocked;
     options.generator.model_path = model_path;
 
@@ -172,6 +184,19 @@ int main(const int argc, char** argv) {
     const auto sampling =
         options.generator.sampling.value_or(SamplingOptions{});
 
+    // Scenario 4: Validate the prompt directory up-front, before any DI
+    // wiring, so the error surfaces immediately with a clear message.
+    std::unique_ptr<IPromptDirectory> prompt_directory;
+    if (!options.generator.use_mocked) {
+      try {
+        prompt_directory =
+            std::make_unique<PromptDirectory>(options.pipeline.prompt_dir);
+      } catch (const std::exception& dir_error) {
+        spdlog::error("[Startup] Invalid --prompt-dir: {}", dir_error.what());
+        return 1;
+      }
+    }
+
     const auto injector = di::make_injector(
         di::bind<WebClient>().to<CURLWebClient>(),
         di::bind<ApplicationOptions>().to(options),
@@ -180,8 +205,8 @@ int main(const int argc, char** argv) {
         di::bind<IPromptFormatter>().to<Gemma4JinjaPromptFormatter>(),
         di::bind<std::string>().to(model_path),
         di::bind<DataGenerator>().to(
-            [options, model_path,
-             sampling](const auto& inj) -> std::unique_ptr<DataGenerator> {
+            [options, model_path, sampling, &prompt_directory](
+                const auto& inj) -> std::unique_ptr<DataGenerator> {
               if (options.generator.use_mocked) {
                 spdlog::info(
                     "[Generator] Using MockGenerator (no model path provided)");
@@ -193,7 +218,13 @@ int main(const int argc, char** argv) {
                   "top-p={}, top-k={}, n_ctx={}, seed={})",
                   model_path, sampling.temperature, sampling.top_p,
                   sampling.top_k, sampling.n_ctx, sampling.seed);
-              return inj.template create<std::unique_ptr<LlamaGenerator>>();
+              // Transfer ownership of the pre-validated PromptDirectory into
+              // the LlamaGenerator.  The lambda captures by reference so the
+              // unique_ptr is moved exactly once.
+              return std::make_unique<LlamaGenerator>(
+                  options, model_path,
+                  inj.template create<std::unique_ptr<IPromptFormatter>>(),
+                  std::move(prompt_directory));
             }));
 
     auto generator =

tooling/pipeline/src/services/prompt_directory.cc

@@ -0,0 +1,85 @@
+/**
+ * @file services/prompt_directory.cc
+ * @brief PromptDirectory implementation: validates the directory at
+ * construction and loads named prompt files on demand with in-process caching.
+ */
+
+#include "services/prompt_directory.h"
+
+#include <spdlog/spdlog.h>
+
+#include <filesystem>
+#include <fstream>
+#include <stdexcept>
+#include <string>
+#include <string_view>
+
+// ---------------------------------------------------------------------------
+// PromptDirectory
+// ---------------------------------------------------------------------------
+
+PromptDirectory::PromptDirectory(const std::filesystem::path& prompt_dir)
+    : prompt_dir_(prompt_dir) {
+  std::error_code ec;
+
+  // Scenario 4: directory must exist.
+  if (!std::filesystem::exists(prompt_dir_, ec) || ec) {
+    throw std::runtime_error(
+        "PromptDirectory: prompt directory does not exist: " +
+        prompt_dir_.string());
+  }
+
+  // Scenario 4: path must be a directory, not a file.
+  if (!std::filesystem::is_directory(prompt_dir_, ec) || ec) {
+    throw std::runtime_error(
+        "PromptDirectory: prompt directory path is not a directory: " +
+        prompt_dir_.string());
+  }
+
+  // Scenario 4: directory must be readable (probe with directory_iterator).
+  std::filesystem::directory_iterator probe(prompt_dir_, ec);
+  if (ec) {
+    throw std::runtime_error(
+        "PromptDirectory: prompt directory is not readable: " +
+        prompt_dir_.string() + " (" + ec.message() + ")");
+  }
+
+  spdlog::info("[PromptDirectory] Resolved prompt directory: {}",
+               prompt_dir_.string());
+}
+
+std::string PromptDirectory::Load(std::string_view key) {
+  const std::string key_str(key);
+
+  // Return cached content if already loaded during this run.
+  const auto cache_it = cache_.find(key_str);
+  if (cache_it != cache_.end()) {
+    return cache_it->second;
+  }
+
+  // Scenario 3: resolve <prompt_dir>/<key>.md and require it to exist.
+  const std::filesystem::path file_path =
+      prompt_dir_ / std::filesystem::path(key_str + ".md");
+
+  std::ifstream file(file_path);
+  if (!file.is_open()) {
+    throw std::runtime_error(
+        "PromptDirectory: prompt file not found for key '" + key_str +
+        "': " + file_path.string());
+  }
+
+  std::string content((std::istreambuf_iterator<char>(file)),
+                      std::istreambuf_iterator<char>());
+  file.close();
+
+  if (content.empty()) {
+    throw std::runtime_error("PromptDirectory: prompt file for key '" +
+                             key_str + "' is empty: " + file_path.string());
+  }
+
+  spdlog::info("[PromptDirectory] Loaded prompt '{}' from '{}' ({} chars)",
+               key_str, file_path.string(), content.size());
+
+  cache_.emplace(key_str, content);
+  return content;
+}