using venv

CMakeLists.txt

@@ -2,9 +2,20 @@ cmake_minimum_required(VERSION 3.14)
 
 project(sbe-code-gen)
 
-find_package(PythonInterp 3.4 REQUIRED)
-
-set(CPP_CODE_GEN_ROOT ${CMAKE_CURRENT_SOURCE_DIR})
+find_package(Python3 REQUIRED COMPONENTS Interpreter)
+
+set(cppCodeGenRoot ${CMAKE_CURRENT_SOURCE_DIR})
+set(pythonEnvPath ${CMAKE_CURRENT_BINARY_DIR}/venv)
+set(pythonEnv ${pythonEnvPath}/bin/python)
+
+add_custom_command(
+  OUTPUT ${pythonEnv}
+  COMMAND ${Python3_EXECUTABLE} -m venv ${pythonEnvPath}
+  DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/requirements.txt
+  COMMAND ${pythonEnv} -m pip install --upgrade pip
+  COMMAND ${pythonEnv} -m pip install -r ${CMAKE_CURRENT_SOURCE_DIR}/requirements.txt
+)
+add_custom_target(venv DEPENDS ${pythonEnv})
 
 function(SBEMakeCodec TARGET)
   set(options)
@@ -15,23 +26,17 @@ function(SBEMakeCodec TARGET)
 
   add_custom_command(
     OUTPUT ${PARSED_OUTPUT}/schema.h
-    COMMAND ${PYTHON_EXECUTABLE} -m app --schema="${PARSED_SCHEMA}" --destination="${PARSED_OUTPUT}" --generator="${PARSED_GENERATOR}"
-    DEPENDS ${PARSED_SCHEMA}
-    WORKING_DIRECTORY ${CPP_CODE_GEN_ROOT}
+    DEPENDS ${PARSED_SCHEMA} venv
+    COMMAND ${pythonEnv} -m app --schema="${PARSED_SCHEMA}" --destination="${PARSED_OUTPUT}" --generator="${PARSED_GENERATOR}"
+    WORKING_DIRECTORY ${cppCodeGenRoot}
     COMMENT "generating schema (${PARSED_SCHEMA})"
   )
 
   add_library(${TARGET} INTERFACE)
   target_compile_features(${TARGET} INTERFACE cxx_std_20)
-  target_sources(${TARGET} PUBLIC ${PARSED_OUTPUT}/schema.h)
+  target_sources(${TARGET} INTERFACE ${PARSED_OUTPUT}/schema.h)
   target_include_directories(${TARGET} INTERFACE "${PARSED_OUTPUT}")
 endfunction()
 
-add_custom_target(InstallRequirements
-  COMMAND ${PYTHON_EXECUTABLE} -m pip install -r requirements.txt
-  WORKING_DIRECTORY ${CPP_CODE_GEN_ROOT}
-  COMMENT install requirements
-)
-
 add_subdirectory(tests EXCLUDE_FROM_ALL)
 add_subdirectory(example EXCLUDE_FROM_ALL)