Add Nix flake support and a NixOS module

2026-03-28-pr.md

@@ -0,0 +1,23 @@
+# PR Title
+
+Add Nix flake support and fix musl build configuration
+
+# PR Body
+
+## Summary
+
+- add a Nix flake with a default package, dev shell, portable musl build, and exported NixOS module
+- add a NixOS module plus README and maintainer docs for running `etserver` from declarative config
+- fix the non-vcpkg and musl build path by gating Catch2 on `BUILD_TESTING`, adding protobuf/absl/`utf8_range` link handling, and improving static `libunwind` linking
+- make `format.sh` work in Nix environments by falling back to `clang-format` or `nix run` when `clang-format-18` is not present
+
+## Testing
+
+- `bash format.sh`
+- `nix develop path:. --command bash -lc 'cmake -S . -B build -GNinja -DDISABLE_VCPKG=ON -DDISABLE_TELEMETRY=ON'`
+- `nix develop path:. --command bash -lc 'cmake --build build -j"$(nproc)"'`
+- `nix develop path:. --command bash -lc 'ctest --test-dir build --parallel "$(nproc)"'`
+
+## Notes
+
+- this keeps the Nix and musl work without reintroducing generated `build-musl/` artifacts or oversized binaries

CMakeLists.txt

@@ -113,6 +113,8 @@ project(EternalTCP VERSION 6.2.11 LANGUAGES C CXX)
 
 include(CMakeFindDependencyMacro)
 
+option(BUILD_TESTING "Build tests" ON)
+
 # Add cmake script directory.
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake")
 set(CMAKE_MODULE_PATH "${EXTERNAL_DIR}/sanitizers-cmake/cmake" ${CMAKE_MODULE_PATH})
@@ -131,7 +133,9 @@ find_package(Protobuf REQUIRED)
 find_package(Unwind)
 
 if(DISABLE_VCPKG)
-  add_subdirectory(${EXTERNAL_DIR}/Catch2)
+  if(BUILD_TESTING)
+    add_subdirectory(${EXTERNAL_DIR}/Catch2)
+  endif()
   add_subdirectory(${EXTERNAL_DIR}/cxxopts)
   add_subdirectory(${EXTERNAL_DIR}/cpp-httplib)
   add_subdirectory(${EXTERNAL_DIR}/json)
@@ -144,7 +148,9 @@ if(DISABLE_VCPKG)
     ${EXTERNAL_DIR}/cxxopts/include
   )
 else()
-  find_package(Catch2 CONFIG REQUIRED)
+  if(BUILD_TESTING)
+    find_package(Catch2 CONFIG REQUIRED)
+  endif()
   find_package(httplib CONFIG REQUIRED)
   find_package(cxxopts CONFIG REQUIRED)
   find_package(nlohmann_json CONFIG REQUIRED)
@@ -210,7 +216,6 @@ endif()
 
 option(CODE_COVERAGE "Enable code coverage" OFF)
 option(FUZZING "Enable builds for fuzz testing" OFF)
-option(BUILD_TESTING "Build tests" ON)
 option(DISABLE_CRASH_LOG "Disable installing easylogging crash handler" OFF)
 option(INSTALL_BASH_COMPLETION "Install bash completion script" ON)
 option(INSTALL_ZSH_COMPLETION "Install zsh completion script" ON)
@@ -261,8 +266,57 @@ set(PROTOBUF_LIBS protobuf::libprotobuf)
 if(Protobuf_VERSION VERSION_GREATER_EQUAL 4)
   find_package(absl REQUIRED)
   find_package(utf8_range CONFIG REQUIRED)
+  set(PROTOBUF_ABSL_LIBS
+    absl::absl_check
+    absl::absl_log
+    absl::algorithm
+    absl::base
+    absl::bind_front
+    absl::bits
+    absl::btree
+    absl::cleanup
+    absl::cord
+    absl::core_headers
+    absl::debugging
+    absl::die_if_null
+    absl::dynamic_annotations
+    absl::flags
+    absl::flat_hash_map
+    absl::flat_hash_set
+    absl::function_ref
+    absl::hash
+    absl::layout
+    absl::log_globals
+    absl::log_initialize
+    absl::log_internal_check_op
+    absl::log_severity
+    absl::memory
+    absl::node_hash_map
+    absl::node_hash_set
+    absl::optional
+    absl::random_distributions
+    absl::random_random
+    absl::span
+    absl::status
+    absl::statusor
+    absl::strings
+    absl::synchronization
+    absl::time
+    absl::utility
+    utf8_range::utf8_validity
+    utf8_range::utf8_range
+  )
 
-  set(PROTOBUF_LIBS ${PROTOBUF_LIBS} absl::log_internal_check_op utf8_range::utf8_validity utf8_range::utf8_range)
+  if(Protobuf_USE_STATIC_LIBS)
+    set(PROTOBUF_LIBS
+      -Wl,--start-group
+      ${PROTOBUF_LIBS}
+      ${PROTOBUF_ABSL_LIBS}
+      -Wl,--end-group
+    )
+  else()
+    set(PROTOBUF_LIBS ${PROTOBUF_LIBS} ${PROTOBUF_ABSL_LIBS})
+  endif()
 endif()
 
 if(SELINUX_FOUND)
@@ -322,7 +376,6 @@ else()
     resolv
     atomic
     stdc++fs
-    anl
   )
 endif()
 

NIXOS-readme.md

@@ -0,0 +1,92 @@
+# EternalTerminal on NixOS
+
+This repo adds Nix support on top of the upstream CMake and Debian-style packaging.
+
+## Changes from base
+
+- `flake.nix` adds:
+  - `packages.default` and `packages.eternal-terminal`
+  - `devShells.default`
+  - `nixosModules.default` and `nixosModules.eternalTerminal`
+- `default.nix` adds a NixOS module for running `etserver`
+- `CMakeLists.txt` gates Catch2 behind `BUILD_TESTING=ON` so Nix package builds do not pull test-only dependencies
+
+## Nix behavior in this repo
+
+- Flake builds use `DISABLE_VCPKG=ON`, `DISABLE_SENTRY=ON`, `DISABLE_TELEMETRY=ON`, and `BUILD_TESTING=OFF`.
+- The flake uses `inputs.self.submodules = true`, so consumers fetch the vendored submodules needed by the build.
+- The package source is filtered with `lib.cleanSourceWith` so local `build/`, `cov_build/`, and `result/` directories do not leak into Nix builds.
+
+## Using it with Nix
+
+For a local checkout, use `path:.`:
+
+```bash
+nix flake show path:.
+nix develop path:.
+nix build path:. --no-link
+```
+
+`nix develop` gives you a shell with the package inputs and the extra developer tools needed for normal CMake work on NixOS.
+
+## Using it with NixOS: module + package
+
+Common setup: import the NixOS module for the service, and add the package if you also want the client tools in `PATH`.
+
+The module manages the server side:
+
+- generates `/etc/et.cfg`
+- starts `etserver` from the selected package
+- opens the configured port when `openFirewall = true`
+
+Example flake-based NixOS configuration:
+
+```nix
+{
+  inputs.et.url = "github:MisterTea/EternalTerminal";
+
+  outputs = { nixpkgs, et, ... }: {
+    nixosConfigurations.my-host = nixpkgs.lib.nixosSystem {
+      system = "x86_64-linux";
+      modules = [
+        et.nixosModules.default
+        ({ pkgs, ... }: {
+          environment.systemPackages = [
+            et.packages.${pkgs.stdenv.hostPlatform.system}.default
+          ];
+
+          services.eternalTerminal = {
+            enable = true;
+            openFirewall = true;
+            port = 2022;
+            settings.Networking.bind_ip = "0.0.0.0";
+          };
+        })
+      ];
+    };
+  };
+}
+```
+
+Notes:
+
+- The module runs the server, but it does not add the client tools to `PATH` by itself. Add the package to `environment.systemPackages` if you also want `et`, `htm`, and the other binaries available interactively.
+- When imported through the flake, `services.eternalTerminal.package` defaults to the flake package.
+- When importing `./default.nix` directly, set `services.eternalTerminal.package` yourself.
+
+## Module options
+
+- `services.eternalTerminal.enable`
+- `services.eternalTerminal.package`
+- `services.eternalTerminal.port`
+- `services.eternalTerminal.openFirewall`
+- `services.eternalTerminal.settings`
+
+`services.eternalTerminal.settings` is written as INI sections into `/etc/et.cfg`. `Networking.port` is always taken from `services.eternalTerminal.port`.
+
+## Service checks
+
+```bash
+systemctl status eternal-terminal
+journalctl -u eternal-terminal -b
+```

README.md

@@ -130,6 +130,34 @@ make
 sudo make install
 ```
 
+### NixOS
+
+If you use flakes, you can import the bundled NixOS module and let it manage
+the package, `/etc/et.cfg`, and the `etserver` service:
+
+```nix
+{
+  inputs.et.url = "github:MisterTea/EternalTerminal";
+
+  outputs = { nixpkgs, et, ... }: {
+    nixosConfigurations.my-host = nixpkgs.lib.nixosSystem {
+      system = "x86_64-linux";
+      modules = [
+        et.nixosModules.default
+        ({ ... }: {
+          services.eternalTerminal = {
+            enable = true;
+            openFirewall = true;
+            port = 2022;
+            settings.Networking.bind_ip = "0.0.0.0";
+          };
+        })
+      ];
+    };
+  };
+}
+```
+
 ### Windows
 
 Eternal Terminal works under WSL (Windows Subsystem for Linux). Follow the ubuntu instructions.
@@ -148,7 +176,10 @@ You are ready to start using ET!
 
 ## Configuring
 
-If you'd like to modify the server settings (e.g. to change the listening port), edit /etc/et.cfg.
+If you'd like to modify the server settings (e.g. to change the listening
+port), edit `/etc/et.cfg`. On NixOS, set `services.eternalTerminal.settings`
+instead so the generated `/etc/et.cfg` stays in sync with your system
+configuration.
 
 ## Using
 

cmake/FindUnwind.cmake

@@ -12,6 +12,13 @@ if (PKG_CONFIG_FOUND)
   pkg_check_modules(PC_UNWIND QUIET libunwind)
 endif()
 
+if (PC_UNWIND_FOUND)
+  set(Unwind_EXTRA_LIBRARIES ${PC_UNWIND_LINK_LIBRARIES})
+  if (PC_UNWIND_STATIC_LINK_LIBRARIES)
+    set(Unwind_STATIC_EXTRA_LIBRARIES ${PC_UNWIND_STATIC_LINK_LIBRARIES})
+  endif()
+endif()
+
 find_path (Unwind_INCLUDE_DIR
   NAMES unwind.h libunwind.h
   HINTS ${PC_UNWIND_INCLUDE_DIRS}
@@ -89,13 +96,23 @@ find_package_handle_standard_args (Unwind REQUIRED_VARS Unwind_INCLUDE_DIR
 
 if (Unwind_FOUND)
   if (NOT TARGET unwind::unwind)
+    set(_Unwind_LINK_LIBRARIES ${Unwind_LIBRARY} ${Unwind_PLATFORM_LIBRARY})
+    if (Unwind_LIBRARY MATCHES "\\.a$")
+      list(APPEND _Unwind_LINK_LIBRARIES ${Unwind_STATIC_EXTRA_LIBRARIES})
+      if (UNIX)
+        list(APPEND _Unwind_LINK_LIBRARIES lzma)
+      endif()
+    else()
+      list(APPEND _Unwind_LINK_LIBRARIES ${Unwind_EXTRA_LIBRARIES})
+    endif()
+
     add_library (unwind::unwind INTERFACE IMPORTED)
 
     set_property (TARGET unwind::unwind PROPERTY
       INTERFACE_INCLUDE_DIRECTORIES ${Unwind_INCLUDE_DIR}
     )
     set_property (TARGET unwind::unwind PROPERTY
-      INTERFACE_LINK_LIBRARIES ${Unwind_LIBRARY} ${Unwind_PLATFORM_LIBRARY}
+      INTERFACE_LINK_LIBRARIES ${_Unwind_LINK_LIBRARIES}
     )
     set_property (TARGET unwind::unwind PROPERTY
       IMPORTED_CONFIGURATIONS RELEASE