[PATCH 05/10] meson: utils: Provide environment for Python scripts

Laurent Pinchart laurent.pinchart at ideasonboard.com
Fri Aug 9 02:59:09 CEST 2024


Python scripts run as part of the build process need to take a few
actions specific to the environment in which they operate. One of those
is disabling the Python bytecode cache, to avoid writing file to the
source tree. This is done manually in the IPC generate.py and parser.py
scripts.

The current implementation is not ideal because it hardcodes in the
scripts information related to the environment in which they operate. As
those scripts are part of libcamera this is more of a theoretical issue
than a practical one. A second issue is that future Python scripts will
need to duplicate similar mechanisms, resulting in a higher maintenance
burden.

Address the issue with a different approach, by creating a meson
environment for the Python scripts, and passing it to the
custom_target() functions. The environment only disables the bytecode
cache for now.

The diffstat shows an increase in code size. This is expected to be
offset by usage of the environment for more Python scripts, as well as
support of more variables in the environment.

Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 include/libcamera/ipa/meson.build             | 21 ++++++++++++-------
 src/libcamera/proxy/meson.build               |  3 ++-
 src/libcamera/proxy/worker/meson.build        |  3 ++-
 .../include/libcamera/ipa/meson.build         |  9 +++++---
 utils/codegen/ipc/generate.py                 |  3 ---
 utils/codegen/ipc/meson.build                 |  3 ++-
 utils/codegen/ipc/parser.py                   |  3 ---
 utils/codegen/meson.build                     |  4 ++++
 8 files changed, 30 insertions(+), 19 deletions(-)

diff --git a/include/libcamera/ipa/meson.build b/include/libcamera/ipa/meson.build
index 96fca42cc0b8..bf55e124e97e 100644
--- a/include/libcamera/ipa/meson.build
+++ b/include/libcamera/ipa/meson.build
@@ -26,7 +26,8 @@ ipa_mojom_core = custom_target(core_mojom_file.split('.')[0] + '_mojom_module',
                                    '--output-root', meson.project_build_root(),
                                    '--input-root', meson.project_source_root(),
                                    '--mojoms', '@INPUT@'
-                               ])
+                               ],
+                               env : py_build_env)
 
 # core_ipa_interface.h
 libcamera_ipa_headers += custom_target('core_ipa_interface_h',
@@ -42,7 +43,8 @@ libcamera_ipa_headers += custom_target('core_ipa_interface_h',
                       '--libcamera_generate_core_header',
                       '--libcamera_output_path=@OUTPUT@',
                       './' +'@INPUT@'
-                  ])
+                  ],
+                  env : py_build_env)
 
 # core_ipa_serializer.h
 libcamera_ipa_headers += custom_target('core_ipa_serializer_h',
@@ -56,7 +58,8 @@ libcamera_ipa_headers += custom_target('core_ipa_serializer_h',
                       '--libcamera_generate_core_serializer',
                       '--libcamera_output_path=@OUTPUT@',
                       './' +'@INPUT@'
-                  ])
+                  ],
+                  env : py_build_env)
 
 # Mapping from pipeline handler name to mojom file
 pipeline_ipa_mojom_mapping = {
@@ -99,7 +102,8 @@ foreach pipeline, file : pipeline_ipa_mojom_mapping
                               '--output-root', meson.project_build_root(),
                               '--input-root', meson.project_source_root(),
                               '--mojoms', '@INPUT@'
-                          ])
+                          ],
+                          env : py_build_env)
 
     # {interface}_ipa_interface.h
     header = custom_target(name + '_ipa_interface_h',
@@ -115,7 +119,8 @@ foreach pipeline, file : pipeline_ipa_mojom_mapping
                                '--libcamera_generate_header',
                                '--libcamera_output_path=@OUTPUT@',
                                './' +'@INPUT@'
-                           ])
+                           ],
+                           env : py_build_env)
 
     # {interface}_ipa_serializer.h
     serializer = custom_target(name + '_ipa_serializer_h',
@@ -129,7 +134,8 @@ foreach pipeline, file : pipeline_ipa_mojom_mapping
                                    '--libcamera_generate_serializer',
                                    '--libcamera_output_path=@OUTPUT@',
                                    './' +'@INPUT@'
-                               ])
+                               ],
+                               env : py_build_env)
 
     # {interface}_ipa_proxy.h
     proxy_header = custom_target(name + '_proxy_h',
@@ -143,7 +149,8 @@ foreach pipeline, file : pipeline_ipa_mojom_mapping
                                      '--libcamera_generate_proxy_h',
                                      '--libcamera_output_path=@OUTPUT@',
                                      './' +'@INPUT@'
-                                 ])
+                                 ],
+                                 env : py_build_env)
 
     ipa_mojoms += {
         'name': name,
diff --git a/src/libcamera/proxy/meson.build b/src/libcamera/proxy/meson.build
index d7de518a0549..8bd1b135d0f5 100644
--- a/src/libcamera/proxy/meson.build
+++ b/src/libcamera/proxy/meson.build
@@ -13,7 +13,8 @@ foreach mojom : ipa_mojoms
                               '--libcamera_generate_proxy_cpp',
                               '--libcamera_output_path=@OUTPUT@',
                               './' + '@INPUT@'
-                          ])
+                          ],
+                          env : py_build_env)
 
     libcamera_internal_sources += proxy
 endforeach
diff --git a/src/libcamera/proxy/worker/meson.build b/src/libcamera/proxy/worker/meson.build
index b5ab9794c622..8c54a2e206a5 100644
--- a/src/libcamera/proxy/worker/meson.build
+++ b/src/libcamera/proxy/worker/meson.build
@@ -15,7 +15,8 @@ foreach mojom : ipa_mojoms
                                '--libcamera_generate_proxy_worker',
                                '--libcamera_output_path=@OUTPUT@',
                                './' + '@INPUT@'
-                           ])
+                           ],
+                           env : py_build_env)
 
     proxy = executable(mojom['name'] + '_ipa_proxy', worker,
                        install : true,
diff --git a/test/serialization/generated_serializer/include/libcamera/ipa/meson.build b/test/serialization/generated_serializer/include/libcamera/ipa/meson.build
index 6f8794c188a3..ae08e9bee6b9 100644
--- a/test/serialization/generated_serializer/include/libcamera/ipa/meson.build
+++ b/test/serialization/generated_serializer/include/libcamera/ipa/meson.build
@@ -9,7 +9,8 @@ mojom = custom_target('test_mojom_module',
                           '--output-root', meson.project_build_root(),
                           '--input-root', meson.project_source_root(),
                           '--mojoms', '@INPUT@'
-                      ])
+                      ],
+                      env : py_build_env)
 
 # test_ipa_interface.h
 generated_test_header = custom_target('test_ipa_interface_h',
@@ -23,7 +24,8 @@ generated_test_header = custom_target('test_ipa_interface_h',
                            '--libcamera_generate_header',
                            '--libcamera_output_path=@OUTPUT@',
                            './' +'@INPUT@'
-                       ])
+                       ],
+                       env : py_build_env)
 
 # test_ipa_serializer.h
 generated_test_serializer = custom_target('test_ipa_serializer_h',
@@ -37,4 +39,5 @@ generated_test_serializer = custom_target('test_ipa_serializer_h',
                                '--libcamera_generate_serializer',
                                '--libcamera_output_path=@OUTPUT@',
                                './' +'@INPUT@'
-                           ])
+                           ],
+                           env : py_build_env)
diff --git a/utils/codegen/ipc/generate.py b/utils/codegen/ipc/generate.py
index c2b3fcb72e1f..dfbe659bc0ca 100755
--- a/utils/codegen/ipc/generate.py
+++ b/utils/codegen/ipc/generate.py
@@ -9,9 +9,6 @@
 import os
 import sys
 
-# TODO set sys.pycache_prefix for >= python3.8
-sys.dont_write_bytecode = True
-
 sys.path.insert(0, f'{os.path.dirname(__file__)}/mojo/public/tools/bindings')
 
 import mojo.public.tools.bindings.mojom_bindings_generator as generator
diff --git a/utils/codegen/ipc/meson.build b/utils/codegen/ipc/meson.build
index 973a5417dc99..f77bf32497ba 100644
--- a/utils/codegen/ipc/meson.build
+++ b/utils/codegen/ipc/meson.build
@@ -13,6 +13,7 @@ mojom_docs_extractor = find_program('./extract-docs.py')
 mojom_templates = custom_target('mojom_templates',
                                 input : mojom_template_files,
                                 output : 'libcamera_templates.zip',
-                                command : [mojom_generator, '-o', '@OUTDIR@', 'precompile'])
+                                command : [mojom_generator, '-o', '@OUTDIR@', 'precompile'],
+                                env : py_build_env)
 
 mojom_templates_dir = meson.current_build_dir()
diff --git a/utils/codegen/ipc/parser.py b/utils/codegen/ipc/parser.py
index cb5608b7c165..8e70322d1bdb 100755
--- a/utils/codegen/ipc/parser.py
+++ b/utils/codegen/ipc/parser.py
@@ -9,9 +9,6 @@
 import os
 import sys
 
-# TODO set sys.pycache_prefix for >= python3.8
-sys.dont_write_bytecode = True
-
 # Make sure that mojom_parser.py can import mojom
 sys.path.insert(0, f'{os.path.dirname(__file__)}/mojo/public/tools/mojom')
 
diff --git a/utils/codegen/meson.build b/utils/codegen/meson.build
index 7dd312e16559..fb2196ee0d20 100644
--- a/utils/codegen/meson.build
+++ b/utils/codegen/meson.build
@@ -2,6 +2,10 @@
 
 ## Code generation
 
+py_build_env = environment()
+# \todo Investigate usage of PYTHONPYCACHEPREFIX for Python >= 3.8
+py_build_env.set('PYTHONDONTWRITEBYTECODE', '1')
+
 py_modules += ['jinja2', 'yaml']
 
 gen_controls = files('gen-controls.py')
-- 
Regards,

Laurent Pinchart



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