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_STORAGE_TRANSFER_SERVICE_ENDPOINT=...overrides theEndpointOption(which defaults to "storagetransfer.googleapis.com") used byMakeStorageTransferServiceConnection().
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\u003eThe latest release candidate version for the Storage Transfer service is 2.37.0-rc, and the page provides links to documentation for versions ranging from 2.36.0 down to 2.11.0.\u003c/p\u003e\n"],["\u003cp\u003eEnvironment variables can be used to configure the library's behavior, particularly when troubleshooting issues, and these variables can override settings defined in the code itself.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eGOOGLE_CLOUD_CPP_STORAGE_TRANSFER_SERVICE_ENDPOINT\u003c/code\u003e environment variable can override the default endpoint used by \u003ccode\u003eMakeStorageTransferServiceConnection()\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eTracing for gRPC calls can be enabled using the \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING\u003c/code\u003e environment variable, along with the possibility to use \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG\u003c/code\u003e to produce the output on the console.\u003c/p\u003e\n"],["\u003cp\u003eThe environment variable \u003ccode\u003eGOOGLE_CLOUD_PROJECT\u003c/code\u003e is used to set the default GCP project in examples and integration tests, but it has no impact on the library itself.\u003c/p\u003e\n"]]],[],null,["Version 2.28.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/storagetransfer/latest/storagetransfer-env)\n- [2.41.0](/cpp/docs/reference/storagetransfer/2.41.0/storagetransfer-env)\n- [2.40.0](/cpp/docs/reference/storagetransfer/2.40.0/storagetransfer-env)\n- [2.39.0](/cpp/docs/reference/storagetransfer/2.39.0/storagetransfer-env)\n- [2.38.0](/cpp/docs/reference/storagetransfer/2.38.0/storagetransfer-env)\n- [2.37.0](/cpp/docs/reference/storagetransfer/2.37.0/storagetransfer-env)\n- [2.36.0](/cpp/docs/reference/storagetransfer/2.36.0/storagetransfer-env)\n- [2.35.0](/cpp/docs/reference/storagetransfer/2.35.0/storagetransfer-env)\n- [2.34.0](/cpp/docs/reference/storagetransfer/2.34.0/storagetransfer-env)\n- [2.33.0](/cpp/docs/reference/storagetransfer/2.33.0/storagetransfer-env)\n- [2.32.0](/cpp/docs/reference/storagetransfer/2.32.0/storagetransfer-env)\n- [2.31.0](/cpp/docs/reference/storagetransfer/2.31.0/storagetransfer-env)\n- [2.30.0](/cpp/docs/reference/storagetransfer/2.30.0/storagetransfer-env)\n- [2.29.0](/cpp/docs/reference/storagetransfer/2.29.0/storagetransfer-env)\n- [2.28.0](/cpp/docs/reference/storagetransfer/2.28.0/storagetransfer-env)\n- [2.27.0](/cpp/docs/reference/storagetransfer/2.27.0/storagetransfer-env)\n- [2.26.0](/cpp/docs/reference/storagetransfer/2.26.0/storagetransfer-env)\n- [2.25.1](/cpp/docs/reference/storagetransfer/2.25.1/storagetransfer-env)\n- [2.24.0](/cpp/docs/reference/storagetransfer/2.24.0/storagetransfer-env)\n- [2.23.0](/cpp/docs/reference/storagetransfer/2.23.0/storagetransfer-env)\n- [2.22.1](/cpp/docs/reference/storagetransfer/2.22.1/storagetransfer-env)\n- [2.21.0](/cpp/docs/reference/storagetransfer/2.21.0/storagetransfer-env)\n- [2.20.0](/cpp/docs/reference/storagetransfer/2.20.0/storagetransfer-env)\n- [2.19.0](/cpp/docs/reference/storagetransfer/2.19.0/storagetransfer-env)\n- [2.18.0](/cpp/docs/reference/storagetransfer/2.18.0/storagetransfer-env)\n- [2.17.0](/cpp/docs/reference/storagetransfer/2.17.0/storagetransfer-env)\n- [2.16.0](/cpp/docs/reference/storagetransfer/2.16.0/storagetransfer-env)\n- [2.15.1](/cpp/docs/reference/storagetransfer/2.15.1/storagetransfer-env)\n- [2.14.0](/cpp/docs/reference/storagetransfer/2.14.0/storagetransfer-env)\n- [2.13.0](/cpp/docs/reference/storagetransfer/2.13.0/storagetransfer-env)\n- [2.12.0](/cpp/docs/reference/storagetransfer/2.12.0/storagetransfer-env)\n- [2.11.0](/cpp/docs/reference/storagetransfer/2.11.0/storagetransfer-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_STORAGE_TRANSFER_SERVICE_ENDPOINT=...` overrides the `EndpointOption` (which defaults to \"storagetransfer.googleapis.com\") used by `MakeStorageTransferServiceConnection()`.\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."]]
