gRPC C core based implementations (those contained in this repository) expose some configuration as environment variables that can be set.
GRPC_ABORT_ON_LEAKS A debugging aid to cause a call to abort() when gRPC objects are leaked past grpc_shutdown(). Set to 1 to cause the abort, if unset or 0 it does not abort the process.
GOOGLE_APPLICATION_CREDENTIALS The path to find the credentials to use when Google credentials are created
GRPC_SSL_CIPHER_SUITES A colon separated list of cipher suites to use with OpenSSL Defaults to: ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES256-GCM-SHA384
GRPC_DEFAULT_SSL_ROOTS_FILE_PATH PEM file to load SSL roots from
GRPC_POLL_STRATEGY [posix-style environments only] Declares which polling engines to try when starting gRPC. This is a comma-separated list of engines, which are tried in priority order first -> last. Available polling engines include:
- epoll (linux-only) - a polling engine based around the epoll family of system calls
- poll - a portable polling engine based around poll(), intended to be a fallback engine when nothing better exists
- legacy - the (deprecated) original polling engine for gRPC
GRPC_TRACE A comma separated list of tracers that provide additional insight into how gRPC C core is processing requests via debug logs. Available tracers include:
- api - traces api calls to the C core
- bdp_estimator - traces behavior of bdp estimation logic
- call_error - traces the possible errors contributing to final call status
- channel - traces operations on the C core channel stack
- combiner - traces combiner lock state
- compression - traces compression operations
- connectivity_state - traces connectivity state changes to channels
- channel_stack_builder - traces information about channel stacks being built
- http - traces state in the http2 transport engine
- http1 - traces HTTP/1.x operations performed by gRPC
- flowctl - traces http2 flow control
- op_failure - traces error information when failure is pushed onto a completion queue
- pending_tags - [debug builds only] traces still-in-progress tags on completion queues
- round_robin - traces the round_robin load balancing policy
- glb - traces the grpclb load balancer
- queue_pluck
- queue_timeout
- server_channel - lightweight trace of significant server channel events
- secure_endpoint - traces bytes flowing through encrypted channels
- timer - timers (alarms) in the grpc internals
- transport_security - traces metadata about secure channel establishment
- tcp - traces bytes in and out of a channel
‘all’ can additionally be used to turn all traces on. Individual traces can be disabled by prefixing them with ‘-’.
Example: export GRPC_TRACE=all,-pending_tags
GRPC_VERBOSITY Default gRPC logging verbosity - one of:
- DEBUG - log all gRPC messages
- INFO - log INFO and ERROR message
- ERROR - log only errors
GRPC_DNS_RESOLVER Declares which DNS resolver to use. The default is ares if gRPC is built with c-ares support. Otherwise, the value of this environment variable is ignored. Available DNS resolver include:
- native (default)- a DNS resolver based around getaddrinfo(), creates a new thread to perform name resolution
- ares - a DNS resolver based around the c-ares library