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_DOMAINS_ENDPOINT=...overrides theEndpointOption(which defaults to "domains.googleapis.com") used byMakeDomainsConnection().
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 versioned documentation for the Google Cloud C++ client library, with version 2.37.0-rc being the latest release candidate and links to versions ranging from 2.36.0 down to 2.12.0.\u003c/p\u003e\n"],["\u003cp\u003eThe library's behavior can be configured using various environment variables, which are particularly useful for troubleshooting, alongside the availability of in-code configuration functions.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eGOOGLE_CLOUD_CPP_DOMAINS_ENDPOINT\u003c/code\u003e can be used to override the default endpoint for the \u003ccode\u003eMakeDomainsConnection()\u003c/code\u003e function, allowing for custom endpoint configurations.\u003c/p\u003e\n"],["\u003cp\u003eTracing and logging for gRPC calls can be enabled and customized using \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING\u003c/code\u003e, \u003ccode\u003eGOOGLE_CLOUD_CPP_TRACING_OPTIONS\u003c/code\u003e, and \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG\u003c/code\u003e environment variables, which provide detailed insights into gRPC interactions and overall library activity.\u003c/p\u003e\n"],["\u003cp\u003eThe environment variable \u003ccode\u003eGOOGLE_CLOUD_PROJECT\u003c/code\u003e can be used in examples and integration tests to configure the GCP project, but this is not a library configuration.\u003c/p\u003e\n"]]],[],null,["Version latestkeyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/domains/latest/domains-env)\n- [2.41.0](/cpp/docs/reference/domains/2.41.0/domains-env)\n- [2.40.0](/cpp/docs/reference/domains/2.40.0/domains-env)\n- [2.39.0](/cpp/docs/reference/domains/2.39.0/domains-env)\n- [2.38.0](/cpp/docs/reference/domains/2.38.0/domains-env)\n- [2.37.0](/cpp/docs/reference/domains/2.37.0/domains-env)\n- [2.36.0](/cpp/docs/reference/domains/2.36.0/domains-env)\n- [2.35.0](/cpp/docs/reference/domains/2.35.0/domains-env)\n- [2.34.0](/cpp/docs/reference/domains/2.34.0/domains-env)\n- [2.33.0](/cpp/docs/reference/domains/2.33.0/domains-env)\n- [2.32.0](/cpp/docs/reference/domains/2.32.0/domains-env)\n- [2.31.0](/cpp/docs/reference/domains/2.31.0/domains-env)\n- [2.30.0](/cpp/docs/reference/domains/2.30.0/domains-env)\n- [2.29.0](/cpp/docs/reference/domains/2.29.0/domains-env)\n- [2.28.0](/cpp/docs/reference/domains/2.28.0/domains-env)\n- [2.27.0](/cpp/docs/reference/domains/2.27.0/domains-env)\n- [2.26.0](/cpp/docs/reference/domains/2.26.0/domains-env)\n- [2.25.1](/cpp/docs/reference/domains/2.25.1/domains-env)\n- [2.24.0](/cpp/docs/reference/domains/2.24.0/domains-env)\n- [2.23.0](/cpp/docs/reference/domains/2.23.0/domains-env)\n- [2.22.1](/cpp/docs/reference/domains/2.22.1/domains-env)\n- [2.21.0](/cpp/docs/reference/domains/2.21.0/domains-env)\n- [2.20.0](/cpp/docs/reference/domains/2.20.0/domains-env)\n- [2.19.0](/cpp/docs/reference/domains/2.19.0/domains-env)\n- [2.18.0](/cpp/docs/reference/domains/2.18.0/domains-env)\n- [2.17.0](/cpp/docs/reference/domains/2.17.0/domains-env)\n- [2.16.0](/cpp/docs/reference/domains/2.16.0/domains-env)\n- [2.15.1](/cpp/docs/reference/domains/2.15.1/domains-env)\n- [2.14.0](/cpp/docs/reference/domains/2.14.0/domains-env)\n- [2.13.0](/cpp/docs/reference/domains/2.13.0/domains-env)\n- [2.12.0](/cpp/docs/reference/domains/2.12.0/domains-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_DOMAINS_ENDPOINT=...` overrides the `EndpointOption` (which defaults to \"domains.googleapis.com\") used by `MakeDomainsConnection()`.\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."]]
