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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["\u003cp\u003eThe latest version available is 2.37.0-rc, with numerous other versions dating back to 2.11.0 also accessible via their respective links.\u003c/p\u003e\n"],["\u003cp\u003eEnvironment variables can be utilized to customize the library's operation, offering a practical solution for issue resolution and testing.\u003c/p\u003e\n"],["\u003cp\u003eThe library allows overriding the default endpoint to connect to a local emulator for testing using the \u003ccode\u003eBIGTABLE_EMULATOR_HOST\u003c/code\u003e variable.\u003c/p\u003e\n"],["\u003cp\u003eTracing for gRPC calls, both regular and streaming, can be activated with the \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING\u003c/code\u003e variable, offering insights into request and response activities.\u003c/p\u003e\n"],["\u003cp\u003eLogging can be enabled within the library using the variable \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG\u003c/code\u003e, outputting any logging performed by the library to the console.\u003c/p\u003e\n"]]],[],null,["Version 2.19.0keyboard_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::TracingComponentsOption`](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1TracingComponentsOption.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."]]
