This was accidentally broken by #9627 because during config sync, a config
validation happens that uses `--define System.ZonesStageVarDir=...` which fails
on the now frozen namespace.
This commit changes this to use `Internal.ZonesStageVarDir` instead. After all,
this is used for internal functionality, users should not directly interact
with this flag.
Additionally, it no longer freezes the `Internal` namespace which actually
allows using `Internal.ZonesStageVarDir` in the first place. This also fixes
`--define Internal.Debug*` which was also broken by said PR. Freezing of the
`Internal` namespace is not necessary for performance reasons as it's not
searched implicitly (for example when accessing `globals.x`) and should users
actually interact with it, they should know by that name that they are on their
own.
This can be observed when running something like `icinga2 daemon -C -DTypes.Host=42`.
Without this commit:
[2023-02-01 09:29:00 +0100] critical/Application: Error: Namespace is read-only and must not be modified.
Additional information is available in '/var/log/icinga2/crash/report.1675240140.425155'
With this commit:
[2023-02-01 09:30:37 +0100] critical/icinga-app: cannot set 'Types.Host': Namespace is read-only and must not be modified.
* Add the Option to disable RetryWrites to CheckCommand for newer check_mongodb.py
* Add documentation foor the Option to disable RetryWrites in the MongoDB-Check
This commit moves the initialization of the globals.Types namespace to type.cpp
in order to keep a pointer to the Namespace object in Type::m_Namespace and
simplify Type::GetByName() using it.
The dynamic type check is moved into an assertion after freezing the namespace.
This makes freezing a namespace an irrevocable operation but in return allows
omitting further lock operations. This results in a performance improvement as
reading an atomic bool is faster than acquiring and releasing a shared lock.
ObjectLocks on namespaces remain untouched as these mostly affect write
operations which there should be none of after freezing (if there are some,
they will throw exceptions anyways).
This commit removes EmbeddedNamespaceValue and ConstEmbeddedNamespaceValue and
reduces NamespaceValue down to a simple struct without inheritance or member
functions. The code from these clases is inlined into the Namespace class. The
class hierarchy determining whether a value is const is moved to an attribute
of NamespaceValue.
This is done in preparation for changes to the locking in the Namespace class.
Currently, it relies on a recursive mutex. In the future, a shared mutex
(read/write lock) should be used instead, which cannot allow recursive locking
(without failing or risk deadlocking on lock upgrades). With this change, all
operations requiring a lock for one operation are within one function, no
recursive locking is not needed any more.
This commit adds a new initialization priority `FreezeNamespaces` that is run
last and moves all calls to `Namespace::Freeze()` there. This allows all other
initialization functions to still update namespaces without the use of the
`overrideFrozen` flag.
It also moves the initialization of `System.Platform*` and `System.Build*` to
an initialize function so that these can also be set without setting
`overrideFrozen`.
This is preparation for a following commit that will make the frozen flag in
namespaces finial, no longer allowing it to be overriden (freezing the
namespace will disable locking, so performing further updates would be unsafe).
