Previously, signal handlers were only given a chance to run upon receipt of an
entry in the RPC stream. Since there is no time bound on how long that might
take, there can be an arbitrarily long time gap between receipt of the signal
and the execution of the application's signal handlers.
Signal handlers are only run on the main thread. The cpython implementation
takes great care to ensure that the main thread does not block for an
arbitrarily long period between signal checks.
Our indefinite blocking was due to wait() invocations on condition variables
without a timeout.
This changes all usages of wait() in the the channel implementation to use a
wrapper that is responsive to signals even while waiting on an RPC.
A test has been added to verify this.
Tests are currently disabled under gevent due to
https://github.com/grpc/grpc/issues/18980, but a fix for that has been
found and should be merged shortly.
More generic configuration system is introduced in order to i) unify the
way how modules access the configurations instead of using low-level
get/setenv functions and ii) enable the customization for where configuration
is stored. This could be extended to support flag, file, etc.
Default configuration system uses environment variables as before so
basically this is expected to work just as it did. This behavior can
change by redefining GPR_GLOBAL_CONFIG_DEFINE_*type* macros.
* Migrated configuration
GRPC_CLIENT_CHANNEL_BACKUP_POLL_INTERVAL_MS
GRPC_EXPERIMENTAL_DISABLE_FLOW_CONTROL
GRPC_ABORT_ON_LEAKS
GRPC_NOT_USE_SYSTEM_SSL_ROOTS
Qiancheng Zhao
Lidi Zheng
Richard Belleville
Richard Belleville
Esun Kim
Yunjia Wang
Soheil Hassas Yeganeh
Lidi Zheng
Mehrdad Afshari
Stanley Cheung
Lily Li
Srini Polavarapu
Srini Polavarapu
Muxi Yan
murgatroid99
Alexander Polcyn