works

CLAUDE.md

@@ -0,0 +1,117 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+This repository contains a Docker-based build system for creating statically-linked C++ executables using Alpine Linux and musl libc. It consists of:
+
+1. **dropshell-build-base**: A comprehensive C++ development base image with Drogon web framework and database support
+2. **dropshell-build**: A multi-stage Docker build system that uses the base image to compile C++ projects
+3. **ipdemo**: A sample application demonstrating the build system
+
+## Key Commands
+
+### Building the Base Image
+```bash
+cd build-base
+./build.sh
+```
+This creates the `gitea.jde.nz/public/dropshell-build-base:latest` Docker image with all dependencies.
+
+### Building a Project
+```bash
+./build.sh
+```
+This builds the project defined in `build.sh` (default: ipdemo) and outputs the binary to `output/`.
+
+### Testing the Built Binary
+```bash
+./test.sh
+```
+Runs the compiled binary from `output/` directory.
+
+### Environment Variables
+- `CMAKE_BUILD_TYPE`: Set to "Debug" or "Release" (default: Debug)
+- `PROJECT`: The project name to build (default: ipdemo)
+
+## Architecture and Design
+
+### Build System Structure
+
+The build system uses a two-stage approach:
+
+1. **Base Image** (`dropshell-build-base`): Contains all dependencies compiled from source with static linking:
+   - C++ compiler toolchain with ccache and mold linker
+   - Libraries: OpenSSL, jsoncpp, PostgreSQL, MariaDB, MySQL, SQLite3, cURL, c-ares
+   - Drogon web framework with full database support
+   - All libraries built with `-fPIC` for static linking
+
+2. **Project Build** (`Dockerfile.dropshell-build`): Multi-stage build that:
+   - Uses build cache mounts for faster rebuilds
+   - Runs cmake_prebuild.sh for custom pre-build steps
+   - Generates version information dynamically
+   - Produces a single static binary in a scratch container
+
+### CMake Configuration
+
+The CMakeLists.txt enforces static linking through:
+- `CMAKE_EXE_LINKER_FLAGS` with `-static` flag
+- `CMAKE_FIND_LIBRARY_SUFFIXES` set to `.a`
+- `BUILD_SHARED_LIBS` forced to OFF
+- Custom library paths from the base image
+
+Important: Projects must set CMAKE_PREFIX_PATH and explicitly link PostgreSQL libraries:
+```cmake
+# Set paths for libraries before finding Drogon
+set(CMAKE_PREFIX_PATH ${CMAKE_PREFIX_PATH} 
+    /usr/local/jsoncpp
+    /usr/local/openssl-musl
+    /usr/local/pgsql
+    # ... other library paths
+)
+
+# Additional PostgreSQL libraries needed for static linking
+set(POSTGRESQL_EXTRA_LIBS
+    /usr/local/pgsql/lib/libpgcommon.a
+    /usr/local/pgsql/lib/libpgport.a
+)
+```
+
+### Project Structure for New Applications
+
+New C++ projects should follow this structure:
+```
+project-name/
+├── CMakeLists.txt      # Based on ipdemo example
+├── cmake_prebuild.sh   # Optional pre-build script
+└── src/
+    ├── main.cpp        # Application entry point
+    └── version.hpp.in  # Version template
+```
+
+### Adding New Projects
+
+To build a different project:
+1. Create a directory with the project structure above
+2. Modify `build.sh` to set `PROJECT="your-project-name"`
+3. Run `./build.sh` to build
+
+### Static Linking Details
+
+The system ensures complete static linking by:
+- Using Alpine Linux's musl libc
+- Building all dependencies with `--enable-static --disable-shared`
+- Setting `-fPIC` for position-independent code
+- Using mold linker with `-static` flag
+- Configuring CMake to prefer `.a` libraries
+
+### Database Support
+
+Applications can use:
+- PostgreSQL via libpq at `/usr/local/pgsql/`
+- MySQL via client library at `/usr/local/mysql/`
+- MariaDB via connector at `/usr/local/mariadb-connector-c/`
+- SQLite3 at `/usr/local/sqlite3/`
+
+All database libraries are statically linked into the final binary.

ipdemo/CMakeLists.txt

@@ -96,6 +96,22 @@ set(EXTRA_LIBS
 )
 
 
+# Set paths for libraries before finding Drogon
+set(CMAKE_PREFIX_PATH ${CMAKE_PREFIX_PATH} 
+    /usr/local/jsoncpp
+    /usr/local/openssl-musl
+    /usr/local/pgsql
+    /usr/local/mariadb-connector-c
+    /usr/local/sqlite3
+    /usr/local/mysql
+    /usr/local/cares
+    /usr/local/curl
+)
+
+# Explicitly set jsoncpp paths for Drogon's FindJsoncpp.cmake
+set(JSONCPP_INCLUDE_DIRS /usr/local/jsoncpp/include)
+set(JSONCPP_LIBRARIES /usr/local/jsoncpp/lib/libjsoncpp.a)
+
 ##########
 # If you include the drogon source code locally in your project, use this method to add drogon
 # add_subdirectory(external/drogon)
@@ -105,10 +121,17 @@ find_package(Drogon CONFIG REQUIRED)
 target_link_libraries(${PROJECT_NAME} PRIVATE Drogon::Drogon)
 
 
+# Additional PostgreSQL libraries needed for static linking
+set(POSTGRESQL_EXTRA_LIBS
+    /usr/local/pgsql/lib/libpgcommon.a
+    /usr/local/pgsql/lib/libpgport.a
+)
+
 # Link libraries
 target_link_libraries(${PROJECT_EXE_NAME} PRIVATE
     nlohmann_json::nlohmann_json
     Drogon::Drogon
+    ${POSTGRESQL_EXTRA_LIBS}
     ${EXTRA_LIBS}
 )
 

ipdemo/src/main.cpp

@@ -1,7 +1,10 @@
 #include <iostream>
+#include <memory>
+#include <thread>
+#include <chrono>
 #include <nlohmann/json.hpp>
 
-#include <drogon/HttpClient.h>
+#include <drogon/drogon.h>
 #include "version.hpp"
 #include "assert.hpp"
 
@@ -14,24 +17,36 @@ int main() {
     std::cout << std::endl;
     std::cout << "Retrieving IP address..." << std::endl;
 
-    auto loop = trantor::EventLoop::getEventLoopOfCurrentThread();
+    // Initialize drogon app but don't run it
-    auto client = drogon::HttpClient::newHttpClient("http://ipinfo.io", loop);
+    drogon::app().setLogLevel(trantor::Logger::kError);
-    auto req = drogon::HttpRequest::newHttpRequest();
+    
-    req->setMethod(drogon::Get);
-    req->setPath("/ip");
     std::string ip_body;
     int status = 0;
     bool done = false;
-    client->sendRequest(req, [&](drogon::ReqResult result, const drogon::HttpResponsePtr &resp) {
+    
-        if (result == drogon::ReqResult::Ok && resp) {
+    // Run in a separate thread to avoid event loop conflicts
-            ip_body = resp->body();
+    std::thread worker([&]() {
-            status = resp->statusCode();
+        trantor::EventLoop loop;
-        } else {
+        auto client = drogon::HttpClient::newHttpClient("http://ipinfo.io", &loop);
-            status = 0;
+        auto req = drogon::HttpRequest::newHttpRequest();
-        }
+        req->setMethod(drogon::Get);
-        done = true;
+        req->setPath("/ip");
+        
+        client->sendRequest(req, [&](drogon::ReqResult result, const drogon::HttpResponsePtr &resp) {
+            if (result == drogon::ReqResult::Ok && resp) {
+                ip_body = resp->body();
+                status = resp->statusCode();
+            } else {
+                status = 0;
+            }
+            done = true;
+            loop.quit();
+        });
+        
+        loop.loop();
     });
-    while (!done) loop->loopOnce();
+    
+    worker.join();
 
     ASSERT(status == 200, "Failed to get IP");