Python post-fork handler: exit if grpc shutdown fails

grpc.def

@@ -15,6 +15,7 @@ EXPORTS
     grpc_register_plugin
     grpc_init
     grpc_shutdown
+    grpc_is_initialized
     grpc_version_string
     grpc_g_stands_for
     grpc_completion_queue_factory_lookup

include/grpc/grpc.h

@@ -79,6 +79,12 @@ GRPCAPI void grpc_init(void);
     destroyed. */
 GRPCAPI void grpc_shutdown(void);
 
+/** EXPERIMENTAL. Returns 1 if the grpc library has been initialized.
+    TODO(ericgribkoff) Decide if this should be promoted to non-experimental as
+    part of stabilizing the fork support API, as tracked in
+    https://github.com/grpc/grpc/issues/15334 */
+GRPCAPI int grpc_is_initialized(void);
+
 /** Return a string representing the current version of grpc */
 GRPCAPI const char* grpc_version_string(void);
 

src/core/lib/iomgr/fork_posix.cc

@@ -25,6 +25,7 @@
 #include <string.h>
 
 #include <grpc/fork.h>
+#include <grpc/grpc.h>
 #include <grpc/support/log.h>
 
 #include "src/core/lib/gpr/env.h"
@@ -34,7 +35,6 @@
 #include "src/core/lib/iomgr/executor.h"
 #include "src/core/lib/iomgr/timer_manager.h"
 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
-#include "src/core/lib/surface/init.h"
 
 /*
  * NOTE: FORKING IS NOT GENERALLY SUPPORTED, THIS IS ONLY INTENDED TO WORK

src/core/lib/surface/init.h

@@ -22,6 +22,5 @@
 void grpc_register_security_filters(void);
 void grpc_security_pre_init(void);
 void grpc_security_init(void);
-int grpc_is_initialized(void);
 
 #endif /* GRPC_CORE_LIB_SURFACE_INIT_H */

src/python/grpcio/grpc/_cython/_cygrpc/fork_posix.pyx.pxi

@@ -73,6 +73,10 @@ cdef void __postfork_child() nogil:
         # TODO(ericgribkoff) Check and abort if core is not shutdown
         with _fork_state.fork_in_progress_condition:
             _fork_state.fork_in_progress = False
+    if grpc_is_initialized() > 0:
+        with gil:
+            _LOGGER.error('Failed to shutdown gRPC Core after fork()')
+            os._exit(os.EX_USAGE)
 
 
 def fork_handlers_and_grpc_init():

src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxi

@@ -322,6 +322,7 @@ cdef extern from "grpc/grpc.h":
 
   void grpc_init() nogil
   void grpc_shutdown() nogil
+  int grpc_is_initialized() nogil
 
   ctypedef struct grpc_completion_queue_factory:
     pass

src/ruby/ext/grpc/rb_grpc_imports.generated.c

@@ -38,6 +38,7 @@ grpc_call_details_destroy_type grpc_call_details_destroy_import;
 grpc_register_plugin_type grpc_register_plugin_import;
 grpc_init_type grpc_init_import;
 grpc_shutdown_type grpc_shutdown_import;
+grpc_is_initialized_type grpc_is_initialized_import;
 grpc_version_string_type grpc_version_string_import;
 grpc_g_stands_for_type grpc_g_stands_for_import;
 grpc_completion_queue_factory_lookup_type grpc_completion_queue_factory_lookup_import;
@@ -291,6 +292,7 @@ void grpc_rb_load_imports(HMODULE library) {
   grpc_register_plugin_import = (grpc_register_plugin_type) GetProcAddress(library, "grpc_register_plugin");
   grpc_init_import = (grpc_init_type) GetProcAddress(library, "grpc_init");
   grpc_shutdown_import = (grpc_shutdown_type) GetProcAddress(library, "grpc_shutdown");
+  grpc_is_initialized_import = (grpc_is_initialized_type) GetProcAddress(library, "grpc_is_initialized");
   grpc_version_string_import = (grpc_version_string_type) GetProcAddress(library, "grpc_version_string");
   grpc_g_stands_for_import = (grpc_g_stands_for_type) GetProcAddress(library, "grpc_g_stands_for");
   grpc_completion_queue_factory_lookup_import = (grpc_completion_queue_factory_lookup_type) GetProcAddress(library, "grpc_completion_queue_factory_lookup");

src/ruby/ext/grpc/rb_grpc_imports.generated.h

@@ -89,6 +89,9 @@ extern grpc_init_type grpc_init_import;
 typedef void(*grpc_shutdown_type)(void);
 extern grpc_shutdown_type grpc_shutdown_import;
 #define grpc_shutdown grpc_shutdown_import
+typedef int(*grpc_is_initialized_type)(void);
+extern grpc_is_initialized_type grpc_is_initialized_import;
+#define grpc_is_initialized grpc_is_initialized_import
 typedef const char*(*grpc_version_string_type)(void);
 extern grpc_version_string_type grpc_version_string_import;
 #define grpc_version_string grpc_version_string_import

test/core/surface/public_headers_must_be_c89.c

@@ -77,6 +77,7 @@ int main(int argc, char **argv) {
   printf("%lx", (unsigned long) grpc_register_plugin);
   printf("%lx", (unsigned long) grpc_init);
   printf("%lx", (unsigned long) grpc_shutdown);
+  printf("%lx", (unsigned long) grpc_is_initialized);
   printf("%lx", (unsigned long) grpc_version_string);
   printf("%lx", (unsigned long) grpc_g_stands_for);
   printf("%lx", (unsigned long) grpc_completion_queue_factory_lookup);