gRPC environment variables

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
    • 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
    • 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:

    • ares (default) - a DNS resolver based around the c-ares library
    • native - a DNS resolver based around getaddrinfo(), creates a new thread to perform name resolution