1*cc02d7e2SAndroid Build Coastguard Worker# Troubleshooting gRPC 2*cc02d7e2SAndroid Build Coastguard Worker 3*cc02d7e2SAndroid Build Coastguard WorkerThis guide is for troubleshooting gRPC implementations based on C core library (sources for most of them are living in the `grpc/grpc` repository). 4*cc02d7e2SAndroid Build Coastguard Worker 5*cc02d7e2SAndroid Build Coastguard Worker## Enabling extra logging and tracing 6*cc02d7e2SAndroid Build Coastguard Worker 7*cc02d7e2SAndroid Build Coastguard WorkerExtra logging can be very useful for diagnosing problems. All gRPC implementations based on C core library support 8*cc02d7e2SAndroid Build Coastguard Workerthe `GRPC_VERBOSITY` and `GRPC_TRACE` environment variables that can be used to increase the amount of information 9*cc02d7e2SAndroid Build Coastguard Workerthat gets printed to stderr. 10*cc02d7e2SAndroid Build Coastguard Worker 11*cc02d7e2SAndroid Build Coastguard Worker## GRPC_VERBOSITY 12*cc02d7e2SAndroid Build Coastguard Worker 13*cc02d7e2SAndroid Build Coastguard Worker`GRPC_VERBOSITY` is used to set the minimum level of log messages printed by gRPC (supported values are `DEBUG`, `INFO` and `ERROR`). If this environment variable is unset, only `ERROR` logs will be printed. 14*cc02d7e2SAndroid Build Coastguard Worker 15*cc02d7e2SAndroid Build Coastguard Worker## GRPC_TRACE 16*cc02d7e2SAndroid Build Coastguard Worker 17*cc02d7e2SAndroid Build Coastguard Worker`GRPC_TRACE` can be used to enable extra logging for some internal gRPC components. Enabling the right traces can be invaluable 18*cc02d7e2SAndroid Build Coastguard Workerfor diagnosing for what is going wrong when things aren't working as intended. Possible values for `GRPC_TRACE` are listed in [Environment Variables Overview](doc/environment_variables.md). 19*cc02d7e2SAndroid Build Coastguard WorkerMultiple traces can be enabled at once (use comma as separator). 20*cc02d7e2SAndroid Build Coastguard Worker 21*cc02d7e2SAndroid Build Coastguard Worker``` 22*cc02d7e2SAndroid Build Coastguard Worker# Enable debug logs for an application 23*cc02d7e2SAndroid Build Coastguard WorkerGRPC_VERBOSITY=debug ./helloworld_application_using_grpc 24*cc02d7e2SAndroid Build Coastguard Worker``` 25*cc02d7e2SAndroid Build Coastguard Worker 26*cc02d7e2SAndroid Build Coastguard Worker``` 27*cc02d7e2SAndroid Build Coastguard Worker# Print information about invocations of low-level C core API. 28*cc02d7e2SAndroid Build Coastguard Worker# Note that trace logs of log level DEBUG won't be displayed. 29*cc02d7e2SAndroid Build Coastguard Worker# Also note that most tracers user log level INFO, so without setting 30*cc02d7e2SAndroid Build Coastguard Worker# GPRC_VERBOSITY accordingly, no traces will be printed. 31*cc02d7e2SAndroid Build Coastguard WorkerGRPC_VERBOSITY=info GRPC_TRACE=api ./helloworld_application_using_grpc 32*cc02d7e2SAndroid Build Coastguard Worker``` 33*cc02d7e2SAndroid Build Coastguard Worker 34*cc02d7e2SAndroid Build Coastguard Worker``` 35*cc02d7e2SAndroid Build Coastguard Worker# Print info from 3 different tracers, including tracing logs with log level DEBUG 36*cc02d7e2SAndroid Build Coastguard WorkerGRPC_VERBOSITY=debug GRPC_TRACE=tcp,http,api ./helloworld_application_using_grpc 37*cc02d7e2SAndroid Build Coastguard Worker``` 38*cc02d7e2SAndroid Build Coastguard Worker 39*cc02d7e2SAndroid Build Coastguard WorkerKnown limitations: `GPRC_TRACE=tcp` is currently not implemented for Windows (you won't see any tcp traces). 40*cc02d7e2SAndroid Build Coastguard Worker 41*cc02d7e2SAndroid Build Coastguard WorkerPlease note that the `GRPC_TRACE` environment variable has nothing to do with gRPC's "tracing" feature (= tracing RPCs in 42*cc02d7e2SAndroid Build Coastguard Workermicroservice environment to gain insight about how requests are processed by deployment), it is merely used to enable printing 43*cc02d7e2SAndroid Build Coastguard Workerof extra logs. 44