* `Container Build Time`_

This option defines the charset that is used in the application. This value is

exposed via the ``kernel.charset`` configuration parameter and the

:method:`Symfony\\Component\\HttpKernel\\Kernel::getCharset` method.

To change this value, override the ``getCharset()`` method and return another

charset::

This value is exposed via the ``kernel.name`` configuration parameter and the

:method:`Symfony\\Component\\HttpKernel\\Kernel::getName` method.

To change this setting, override the ``getName()`` method. Alternatively, move

your kernel into a different directory. For example, if you moved the kernel

into a ``foo`` directory (instead of ``app``), the kernel name will be ``foo``.

This returns the absolute path of the directory where your kernel class is

located. If you use the Symfony Standard edition, this is the ``app/`` directory

of your project.

This value is exposed via the ``kernel.root_dir`` configuration parameter and

the :method:`Symfony\\Component\\HttpKernel\\Kernel::getRootDir` method. To

change this setting, override the ``getRootDir()`` method::

This returns the absolute path of the root directory of your Symfony project.

It's calculated automatically as the directory where the main ``composer.json``

file is stored.

This value is exposed via the ``kernel.project_dir`` configuration parameter and

the :method:`Symfony\\Component\\HttpKernel\\Kernel::getProjectDir` method. To

change this setting, override the ``getProjectDir()`` method to return the right

project directory::

This returns the absolute path of the cache directory of your Symfony project.

It's calculated automatically based on the current

:doc:`environment </configuration/environments>`.

This value is exposed via the ``kernel.cache_dir`` configuration parameter and

the :method:`Symfony\\Component\\HttpKernel\\Kernel::getCacheDir` method. To

change this setting, override the ``getCacheDir()`` method to return the right

cache directory.

This returns the absolute path of the log directory of your Symfony project.

It's calculated automatically based on the current

:doc:`environment </configuration/environments>`.

This value is exposed via the ``kernel.log_dir`` configuration parameter and

the :method:`Symfony\\Component\\HttpKernel\\Kernel::getLogDir` method. To

change this setting, override the ``getLogDir()`` method to return the right

log directory.

Container Build Time

**type**: ``string`` **default**: the result of executing ``time()``

Symfony follows the `reproducible builds`_ philosophy, which ensures that the

result of compiling the exact same source code doesn't produce different

results. This helps checking that a given binary or executable code was compiled

from some trusted source code.

In practice, the compiled :doc:`service container </service_container>` of your

application will always be the same if you don't change its source code. This is

exposed via these configuration parameters:

* ``container.build_hash``, a hash of the contents of all your source files;

* ``container.build_time``, a timestamp of the moment when the container was

built (the result of executing PHP's :phpfunction:`time` function);

* ``container.build_id``, the result of merging the two previous parameters and

encoding the result using CRC32.

Since the ``container.build_time`` value will change every time you compile the

application, the build will not be strictly reproducible. If you care about

this, the solution is to use another configuration parameter called

``kernel.container_build_time`` and set it to a non-changing build time to

achieve a strict reproducible build::

.. configuration-block::

.. code-block:: yaml

.. code-block:: xml

.. code-block:: php

.. _`reproducible builds`: https://en.wikipedia.org/wiki/Reproducible_builds