* Icinga daemon leaves zombie processes on very busy system
On a very heavily loaded system the process group kill can
be delayed until after the regular TERM signal has caused
the process to exit. In this situation the waitpid call
is valid and reaps the zombie process that would otherwise
be left behind.
* Update AUTHORS file
First, the icinga_legacytimeperiod/dst test was excluded, as it fails on
Alpine most likely due to some differences between musl and glibc. After
some debugging, I disabled the test as the Alpine packages does.
More build dependencies were added from the Alpine package, allowing to
only disable MySQL and PostgreSQL support as these libraries have fixed
dependencies on OpenSSL, conflicting with LibreSSL.
In addition, I have added comments where I was first puzzled.
Services downtimes scheduled via the `all_services` flag get already
removed automatically when removing their parent downtimes (introduced
with #8913). Now, this commit makes it possible to perform the same actions
for all child downtimes, i.e. not only for those of service objects, but
for all child objects represented in the dependency tree.
`checkable` is already added to the set by the insert call above, so calling
emplace for the same checkable doesn't do anything useful and can be removed.
The previous wasn't per-se wrong, but it was way too inefficient. With
this commit each and every Checkable is going to be visited only once,
and we won't traverse the same Checkable's children multiple times
somewhere in the dependency chain.
The previous limit (32) doesn't seem to make sense, and appears to be some random number.
So, this limit is set to 256 to match the limit in IsReachable().
This commit removes a distinction in how dependency objects are checked for
cycles in the resulting graph depending on whether they are part of the
initially loaded configuration during process startup or as part of a runtime
update.
The DependencyCycleChecker helper class is extended with a mechanism that
allows additional dependencies to be considered during the cycle search. This
allows using it to check for cycles before actually registering the
dependencies with the checkables.
The aforementioned case-distinction for initial/runtime-update config is
removed by making use of the newly added BeforeOnAllConfigLoaded signal to
perform the cycle check at once for each batch of dependencies inside
ConfigItem::CommitNewItems() for both cases now. During the initial config
loading, there can be multiple batches of dependencies as objects from apply
rules are created separately, so parts of the dependency graph might be visited
multiple times now, however that is limited to a minimum as only parts of the
graph that are reachable from the newly added dependencies are searched.
This commit groups a bunch of structs and static functions inside
dependency.cpp into a new DependencyCycleChecker helper class. In the process,
the implementation was changed a bit, the behavior should be unchanged except
for a more user-friendly error message in the exception.
