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::LoggingComponentsOptionGOOGLE_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"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-28 UTC."],[[["\u003cp\u003eThe latest version available is 2.37.0-rc, with numerous previous versions from 2.36.0 down to 2.11.0 also available for reference.\u003c/p\u003e\n"],["\u003cp\u003eEnvironment variables can be set to configure the library's behavior, and can be particularly useful for troubleshooting.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eBIGTABLE_EMULATOR_HOST\u003c/code\u003e allows overriding the default endpoint, typically used for testing purposes with a specified emulator.\u003c/p\u003e\n"],["\u003cp\u003eTracing for gRPC calls can be enabled using \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING\u003c/code\u003e, which can log both regular and streaming RPC calls.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG\u003c/code\u003e enables logging within the library and \u003ccode\u003eGOOGLE_CLOUD_PROJECT\u003c/code\u003e can be set for examples and testing, although it does not directly affect the library.\u003c/p\u003e\n"]]],[],null,["Version latestkeyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/bigtable/latest/bigtable-environment-variables)\n- [2.41.0](/cpp/docs/reference/bigtable/2.41.0/bigtable-environment-variables)\n- [2.40.0](/cpp/docs/reference/bigtable/2.40.0/bigtable-environment-variables)\n- [2.39.0](/cpp/docs/reference/bigtable/2.39.0/bigtable-environment-variables)\n- [2.38.0](/cpp/docs/reference/bigtable/2.38.0/bigtable-environment-variables)\n- [2.37.0](/cpp/docs/reference/bigtable/2.37.0/bigtable-environment-variables)\n- [2.36.0](/cpp/docs/reference/bigtable/2.36.0/bigtable-environment-variables)\n- [2.35.0](/cpp/docs/reference/bigtable/2.35.0/bigtable-environment-variables)\n- [2.34.0](/cpp/docs/reference/bigtable/2.34.0/bigtable-environment-variables)\n- [2.33.0](/cpp/docs/reference/bigtable/2.33.0/bigtable-environment-variables)\n- [2.32.0](/cpp/docs/reference/bigtable/2.32.0/bigtable-environment-variables)\n- [2.31.0](/cpp/docs/reference/bigtable/2.31.0/bigtable-environment-variables)\n- [2.30.0](/cpp/docs/reference/bigtable/2.30.0/bigtable-environment-variables)\n- [2.29.0](/cpp/docs/reference/bigtable/2.29.0/bigtable-environment-variables)\n- [2.28.0](/cpp/docs/reference/bigtable/2.28.0/bigtable-environment-variables)\n- [2.27.0](/cpp/docs/reference/bigtable/2.27.0/bigtable-environment-variables)\n- [2.26.0](/cpp/docs/reference/bigtable/2.26.0/bigtable-environment-variables)\n- [2.25.1](/cpp/docs/reference/bigtable/2.25.1/bigtable-environment-variables)\n- [2.24.0](/cpp/docs/reference/bigtable/2.24.0/bigtable-environment-variables)\n- [2.23.0](/cpp/docs/reference/bigtable/2.23.0/bigtable-environment-variables)\n- [2.22.1](/cpp/docs/reference/bigtable/2.22.1/bigtable-environment-variables)\n- [2.21.0](/cpp/docs/reference/bigtable/2.21.0/bigtable-environment-variables)\n- [2.20.0](/cpp/docs/reference/bigtable/2.20.0/bigtable-environment-variables)\n- [2.19.0](/cpp/docs/reference/bigtable/2.19.0/bigtable-environment-variables)\n- [2.18.0](/cpp/docs/reference/bigtable/2.18.0/bigtable-environment-variables)\n- [2.17.0](/cpp/docs/reference/bigtable/2.17.0/bigtable-environment-variables)\n- [2.16.0](/cpp/docs/reference/bigtable/2.16.0/bigtable-environment-variables)\n- [2.15.1](/cpp/docs/reference/bigtable/2.15.1/bigtable-environment-variables)\n- [2.14.0](/cpp/docs/reference/bigtable/2.14.0/bigtable-environment-variables)\n- [2.13.0](/cpp/docs/reference/bigtable/2.13.0/bigtable-environment-variables)\n- [2.12.0](/cpp/docs/reference/bigtable/2.12.0/bigtable-environment-variables)\n- [2.11.0](/cpp/docs/reference/bigtable/2.11.0/bigtable-environment-variables) \n\nEnvironment Variables\n=====================\n\nA 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.\n\nEndpoint Overrides\n------------------\n\n`BIGTABLE_EMULATOR_HOST=host:port`: tells the library to connect to the specified emulator rather than the default endpoint. Intended for testing only.\n\n###### See Also\n\n[`google::cloud::EndpointOption`](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1EndpointOption.html)\n\nLogging\n-------\n\n`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.\n\n`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.\n\n`GOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc,rpc-streams`: turns on tracing for both regular RPC calls and streaming RPC calls.\n\n###### See Also\n\n[`google::cloud::LoggingComponentsOption`](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1LoggingComponentsOption.html)`GOOGLE_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.\n\n###### See Also\n\n[`google::cloud::GrpcTracingOptionsOption`](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1GrpcTracingOptionsOption.html)`GOOGLE_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.\n\n###### See Also\n\n[`google::cloud::LogBackend`](https://cloud.google.com/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1LogBackend.html)\n\n###### See Also\n\n[`google::cloud::LogSink`](https://cloud.google.com/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1LogSink.html)\n\nSetting the Default Project\n---------------------------\n\n`GOOGLE_CLOUD_PROJECT=...`: is used in examples and integration tests to configure the GCP project. This has no effect in the library."]]
