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charset=\"us-ascii\"","Content-Transfer-Encoding":"7bit","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "},"content":"Describe the environment variables used in libcamera, excluded\nvariables are `LIBCAMERA_IPA_FORCE_C_API` and `LIBCAMERA_IPA_PROXY_PATH`,\nthe former because it is likely to be removed and the later because\nit has no current use-case.\n\nAdd a brief explanation for the IPA configuration and IPA modules.\nList all the available Log levels and categories and add a short guide\non how to use them for debugging.\n\nSigned-off-by: Sebastian Fricke \nReviewed-by: Jacopo Mondi \n\n---\n\nChanges since V3:\n* Rework the LIBCAMERA_LOG_LEVELS explanation\n* improve wording at various places\n* Move the changelog out of the commit description into the email\n\nChanges since V2:\n* replace bullet point list with definition list\n* Remove the category list as it is too difficult to maintain, instead\n explain how the categories are set with the LOG_DECLARE_CATEGORY &\n LOG_DEFINE_CATEGORY macros\n* Remove the short summary for the IPA module, as it can be misleading\n and probably not accurate enough\n* Improve the notes for debugging part by linking to a full explanation\n while extending the description in the documentation as well\n* Add an example for the Log level setting\n* Remove the documentation from guides and add it to the documentation\n base path\n\nChanges since V1:\n* abandon the usage of tables as they are too clunky and difficult to\nmaintain\n* Fix a wrong example that does not work on most distributions and setups\n* Improve structure of log categories\n\n---\n\n Documentation/environment_variables.rst | 132 ++++++++++++++++++++++++\n Documentation/index.rst | 1 +\n Documentation/meson.build | 1 +\n 3 files changed, 134 insertions(+)\n create mode 100644 Documentation/environment_variables.rst","diff":"diff --git a/Documentation/environment_variables.rst b/Documentation/environment_variables.rst\nnew file mode 100644\nindex 0000000..85346af\n--- /dev/null\n+++ b/Documentation/environment_variables.rst\n@@ -0,0 +1,132 @@\n+Environment variables\n+=====================\n+\n+List of variables\n+-----------------\n+\n+LIBCAMERA_LOG_FILE\n+ The custom destination for log output.\n+\n+ Example value: ``/home/{user}/camera_log.log``\n+\n+LIBCAMERA_LOG_LEVELS\n+ Configure the verbosity of log messages for different categories (`more <#log-levels>`__)\n+\n+ Example value: ``*:DEBUG``\n+\n+LIBCAMERA_IPA_CONFIG_PATH\n+ Define custom search locations for IPA configurations (`more <#ipa-configuration>`__)\n+\n+ Example value: ``/usr/path/one:/tmp/path/two``\n+\n+LIBCAMERA_IPA_MODULE_PATH\n+ Define custom search locations for IPA modules (`more <#ipa-module>`__)\n+\n+ Example value: ``/usr/path/one:/tmp/path/two``\n+\n+Further details\n+---------------\n+\n+Notes about debugging\n+~~~~~~~~~~~~~~~~~~~~~\n+\n+The environment variables `LIBCAMERA_LOG_FILE` and `LIBCAMERA_LOG_LEVELS`\n+are used to modify the destination and verbosity of messages provided by\n+libcamera.\n+\n+The `LIBCAMERA_LOG_LEVELS` variable accepts a comma-separated list of\n+'category:level' pairs.\n+\n+The `level <#log-levels>`__ part is mandatory and can either be\n+specified by name or by numerical index associated with each level.\n+\n+The optional `category <#log-categories>`__ part is a regular\n+expression, which is matched against the categories defined by each\n+file in the source base using the logging infrastructure.\n+\n+For more information refer to the `API-documentation `__\n+\n+Examples:\n+\n+Enable full debug output to a separate file, for every `category <#log-categories>`__\n+within a local environment:\n+\n+.. code:: bash\n+\n+ :~$ LIBCAMERA_LOG_FILE='/tmp/example_log.log' \\\n+ LIBCAMERA_LOG_LEVELS=0 \\\n+ cam --list\n+\n+Enable full debug output for the categories Camera & V4L2 within a\n+global environment:\n+\n+.. code:: bash\n+\n+ :~$ export LIBCAMERA_LOG_LEVELS='Camera:DEBUG,V4L2:DEBUG'\n+ :~$ cam --list\n+\n+Log levels\n+~~~~~~~~~~~\n+\n+This is the list of available log levels, notice that all levels below\n+the chosen one are printed, while those above are discarded.\n+\n+- DEBUG (0)\n+- INFO (1)\n+- WARN (2)\n+- ERROR (3)\n+- FATAL (4)\n+\n+Example:\n+If you choose WARN (2), you will be able to see WARN (2), ERROR (3) & FATAL (4)\n+but not DEBUG (0) & INFO (1).\n+\n+Log categories\n+~~~~~~~~~~~~~~~\n+\n+Every category represents a specific area of the libcamera codebase,\n+the names can be located within the source code, for example:\n+`src/libcamera/camera_manager.cpp `__\n+\n+.. code:: bash\n+\n+ LOG_DEFINE_CATEGORY(Camera)\n+\n+There are 2 available macros used to assign a category name to a part of the\n+libcamera codebase:\n+\n+LOG_DEFINE_CATEGORY\n+ This macro is required, in order to use the `LOGC` macro for a\n+\tparticular category. It can only be used once for each category.\n+\tIf you want to create log messages within multiple compilation\n+\tunits for the same category utilize the `LOG_DECLARE_CATEGORY` macro,\n+\tin every file except the definition file.\n+LOG_DECLARE_CATEGORY\n+ Used for sharing an already defined category in between multiple\n+\tseparate compilation units.\n+\n+Both macros have to be used within the libcamera namespace of the C++ source\n+code.\n+\n+IPA configuration\n+~~~~~~~~~~~~~~~~~~\n+\n+The format and contents of the configuration file are specific to the\n+IPA (Image Processing Algorithm). It usually contains tuning parameters\n+for the IPA algorithms stored in JSON format.\n+The `LIBCAMERA_IPA_CONFIG_PATH` variable can be used to specify custom\n+storage locations to search for those configuration files.\n+\n+`Examples `__\n+\n+IPA module\n+~~~~~~~~~~~\n+\n+In order to locate the correct IPA module for your hardware, libcamera gathers\n+existing IPA modules from multiple locations. The default locations for this\n+operation are the installed system path (for example on Debian:\n+``/usr/local/x86_64-pc-linux-gnu/libcamera``) and the build directory.\n+With the `LIBCAMERA_IPA_MODULE_PATH`, you can specify a non-default\n+location to search for IPA modules.\n+\n+`Examples for existing IPA modules `__\ndiff --git a/Documentation/index.rst b/Documentation/index.rst\nindex ff697d4..c49db18 100644\n--- a/Documentation/index.rst\n+++ b/Documentation/index.rst\n@@ -17,3 +17,4 @@\n Application Writer's Guide \n Pipeline Handler Writer's Guide \n Tracing guide \n+ Environment variables \ndiff --git a/Documentation/meson.build b/Documentation/meson.build\nindex 26a12fc..8086abf 100644\n--- a/Documentation/meson.build\n+++ b/Documentation/meson.build\n@@ -53,6 +53,7 @@ if sphinx.found()\n 'contributing.rst',\n 'docs.rst',\n 'index.rst',\n+ 'environment_variables.rst',\n 'guides/introduction.rst',\n 'guides/application-developer.rst',\n 'guides/pipeline-handler.rst',\n","prefixes":["libcamera-devel","v4"]}