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
GOOGLE_CLOUD_CPP_DATA_FUSION_ENDPOINT=...overrides theEndpointOption(which defaults to "datafusion.googleapis.com") used byMakeDataFusionConnection().
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.
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 provides a comprehensive list of Data Fusion C++ library versions, ranging from version 2.13.0 up to the release candidate 2.37.0-rc, with each version having a direct link to its specific documentation.\u003c/p\u003e\n"],["\u003cp\u003eEnvironment variables can be used to configure the behavior of the Data Fusion library, offering a convenient way to troubleshoot issues.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eGOOGLE_CLOUD_CPP_DATA_FUSION_ENDPOINT\u003c/code\u003e variable can override the default endpoint used by \u003ccode\u003eMakeDataFusionConnection()\u003c/code\u003e, allowing for custom endpoint configurations.\u003c/p\u003e\n"],["\u003cp\u003eTracing for gRPC calls can be enabled using the \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc\u003c/code\u003e variable, which prints gRPC requests and responses, and can be further customized using \u003ccode\u003eGOOGLE_CLOUD_CPP_TRACING_OPTIONS\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG=yes\u003c/code\u003e variable enables logging in the library, allowing the logging infrastructure to output information, and the \u003ccode\u003eGOOGLE_CLOUD_PROJECT\u003c/code\u003e variable is useful for examples and integration tests, however it does not affect library behavior.\u003c/p\u003e\n"]]],[],null,["Version 2.33.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/datafusion/latest/datafusion-env)\n- [2.41.0](/cpp/docs/reference/datafusion/2.41.0/datafusion-env)\n- [2.40.0](/cpp/docs/reference/datafusion/2.40.0/datafusion-env)\n- [2.39.0](/cpp/docs/reference/datafusion/2.39.0/datafusion-env)\n- [2.38.0](/cpp/docs/reference/datafusion/2.38.0/datafusion-env)\n- [2.37.0](/cpp/docs/reference/datafusion/2.37.0/datafusion-env)\n- [2.36.0](/cpp/docs/reference/datafusion/2.36.0/datafusion-env)\n- [2.35.0](/cpp/docs/reference/datafusion/2.35.0/datafusion-env)\n- [2.34.0](/cpp/docs/reference/datafusion/2.34.0/datafusion-env)\n- [2.33.0](/cpp/docs/reference/datafusion/2.33.0/datafusion-env)\n- [2.32.0](/cpp/docs/reference/datafusion/2.32.0/datafusion-env)\n- [2.31.0](/cpp/docs/reference/datafusion/2.31.0/datafusion-env)\n- [2.30.0](/cpp/docs/reference/datafusion/2.30.0/datafusion-env)\n- [2.29.0](/cpp/docs/reference/datafusion/2.29.0/datafusion-env)\n- [2.28.0](/cpp/docs/reference/datafusion/2.28.0/datafusion-env)\n- [2.27.0](/cpp/docs/reference/datafusion/2.27.0/datafusion-env)\n- [2.26.0](/cpp/docs/reference/datafusion/2.26.0/datafusion-env)\n- [2.25.1](/cpp/docs/reference/datafusion/2.25.1/datafusion-env)\n- [2.24.0](/cpp/docs/reference/datafusion/2.24.0/datafusion-env)\n- [2.23.0](/cpp/docs/reference/datafusion/2.23.0/datafusion-env)\n- [2.22.1](/cpp/docs/reference/datafusion/2.22.1/datafusion-env)\n- [2.21.0](/cpp/docs/reference/datafusion/2.21.0/datafusion-env)\n- [2.20.0](/cpp/docs/reference/datafusion/2.20.0/datafusion-env)\n- [2.19.0](/cpp/docs/reference/datafusion/2.19.0/datafusion-env)\n- [2.18.0](/cpp/docs/reference/datafusion/2.18.0/datafusion-env)\n- [2.17.0](/cpp/docs/reference/datafusion/2.17.0/datafusion-env)\n- [2.16.0](/cpp/docs/reference/datafusion/2.16.0/datafusion-env)\n- [2.15.1](/cpp/docs/reference/datafusion/2.15.1/datafusion-env)\n- [2.14.0](/cpp/docs/reference/datafusion/2.14.0/datafusion-env)\n- [2.13.0](/cpp/docs/reference/datafusion/2.13.0/datafusion-env) \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- `GOOGLE_CLOUD_CPP_DATA_FUSION_ENDPOINT=...` overrides the `EndpointOption` (which defaults to \"datafusion.googleapis.com\") used by `MakeDataFusionConnection()`.\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###### 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."]]
