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\u003eThis document provides reference information for configuring the behavior of the Storage Transfer Service library using environment variables, which is particularly useful for troubleshooting.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version of the Storage Transfer Service, version 2.37.0-rc, is available, along with a comprehensive list of previous versions, down to version 2.11.0, each with its own specific documentation.\u003c/p\u003e\n"],["\u003cp\u003eEnvironment variables like \u003ccode\u003eGOOGLE_CLOUD_CPP_STORAGE_TRANSFER_SERVICE_ENDPOINT\u003c/code\u003e allow for overriding default endpoints, and \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING\u003c/code\u003e enables detailed tracing for gRPC calls.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG\u003c/code\u003e environment variable is necessary to enable output logging in the library, in addition to the program setting its own backend.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eGOOGLE_CLOUD_PROJECT\u003c/code\u003e is used to configure the GCP project for testing and examples, but it has no impact on the library itself.\u003c/p\u003e\n"]]],[],null,["Version 2.33.0keyboard_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."]]
