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 setGOOGLE_CLOUD_CPP_ENABLE_CLOGto produce any output on the program's console.
GOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc-streams: turns on tracing for streaming gRPC calls, such asTable::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 2025-09-04 UTC."],[[["\u003cp\u003eThis document details environment variables that can configure the behavior of the Bigtable C++ library, offering flexibility beyond in-code configuration.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eBIGTABLE_EMULATOR_HOST\u003c/code\u003e variable allows users to override the default endpoint for testing purposes by connecting to a specified emulator.\u003c/p\u003e\n"],["\u003cp\u003eTracing for gRPC calls and streaming calls can be enabled using \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING\u003c/code\u003e, with options to trace both or specific types of calls, such as \u003ccode\u003erpc\u003c/code\u003e or \u003ccode\u003erpc-streams\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eLogging in the library, which is always present, can be activated to output to the console using \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG\u003c/code\u003e, requiring either a set logging backend, or setting the variable.\u003c/p\u003e\n"],["\u003cp\u003eThe document lists available versions of this library from 2.11.0 to 2.37.0-rc, which is the latest release candidate version.\u003c/p\u003e\n"]]],[],null,["Version 2.30.0keyboard_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::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."]]
