A number of environment variables can be used to configure the behavior of the library. There are also functions to configure this behavior in code. The environment variables are convenient when troubleshooting problems.
Endpoint Overrides
BIGTABLE_EMULATOR_HOST=host:port: tells the library to connect to the specified emulator rather than the default endpoint. Intended for testing only.
GOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc: turns on tracing for most gRPC calls. The library injects an additional Stub decorator that prints each gRPC request and response. Unless you have configured your own logging backend, you should also set GOOGLE_CLOUD_CPP_ENABLE_CLOG to produce any output on the program's console.
GOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc-streams: turns on tracing for streaming gRPC calls, such as Table::ReadRows(). Be warned that streams produce a lot of output.
GOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc,rpc-streams: turns on tracing for both regular RPC calls and streaming RPC calls.
See Also
google::cloud::TracingComponentsOptionGOOGLE_CLOUD_CPP_TRACING_OPTIONS=...: modifies the behavior of gRPC tracing, including whether messages will be output on multiple lines, or whether string/bytes fields will be truncated.
See Also
google::cloud::GrpcTracingOptionsOptionGOOGLE_CLOUD_CPP_ENABLE_CLOG=yes: turns on logging in the library, basically the library always "logs" but the logging infrastructure has no backend to actually print anything until the application sets a backend or they set this environment variable.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-07-09 UTC."],[[["This document details environment variables for configuring the behavior of the Bigtable C++ client library, including options for testing, logging, and tracing gRPC calls."],["The latest release candidate version is 2.37.0-rc, and the document provides links to documentation for many past versions, ranging from 2.36.0 to 2.11.0."],["Environment variables like `BIGTABLE_EMULATOR_HOST` allow overriding the default endpoint for testing purposes, while others like `GOOGLE_CLOUD_CPP_ENABLE_TRACING` and `GOOGLE_CLOUD_CPP_ENABLE_CLOG` are used to manage gRPC tracing and logging output."],["`GOOGLE_CLOUD_PROJECT` can be used in examples and integration tests to set the GCP project, but has no effect on the library itself."]]],[]]
