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_API_KEYS_ENDPOINT=...overrides theEndpointOption(which defaults to "apikeys.googleapis.com") used byMakeApiKeysConnection().
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 API key versions, ranging from the latest release candidate 2.37.0-rc down to version 2.11.0, all accessible via provided links.\u003c/p\u003e\n"],["\u003cp\u003eEnvironment variables, such as \u003ccode\u003eGOOGLE_CLOUD_CPP_API_KEYS_ENDPOINT\u003c/code\u003e, can be utilized to customize the library's behavior, including overriding the default endpoint.\u003c/p\u003e\n"],["\u003cp\u003eTracing for gRPC calls can be enabled via the \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc\u003c/code\u003e environment variable, and more details about configuration can be found in the \u003ccode\u003egoogle::cloud::GrpcTracingOptionsOption\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG=yes\u003c/code\u003e environment variable allows logging to be active in the library, in conjunction with setting a logging backend or just directly to the console.\u003c/p\u003e\n"],["\u003cp\u003eThe library does not use \u003ccode\u003eGOOGLE_CLOUD_PROJECT=...\u003c/code\u003e for its core functionality, only for examples and integration tests, thus having no effect for the library.\u003c/p\u003e\n"]]],[],null,["Version 2.34.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/apikeys/latest/apikeys-env)\n- [2.41.0](/cpp/docs/reference/apikeys/2.41.0/apikeys-env)\n- [2.40.0](/cpp/docs/reference/apikeys/2.40.0/apikeys-env)\n- [2.39.0](/cpp/docs/reference/apikeys/2.39.0/apikeys-env)\n- [2.38.0](/cpp/docs/reference/apikeys/2.38.0/apikeys-env)\n- [2.37.0](/cpp/docs/reference/apikeys/2.37.0/apikeys-env)\n- [2.36.0](/cpp/docs/reference/apikeys/2.36.0/apikeys-env)\n- [2.35.0](/cpp/docs/reference/apikeys/2.35.0/apikeys-env)\n- [2.34.0](/cpp/docs/reference/apikeys/2.34.0/apikeys-env)\n- [2.33.0](/cpp/docs/reference/apikeys/2.33.0/apikeys-env)\n- [2.32.0](/cpp/docs/reference/apikeys/2.32.0/apikeys-env)\n- [2.31.0](/cpp/docs/reference/apikeys/2.31.0/apikeys-env)\n- [2.30.0](/cpp/docs/reference/apikeys/2.30.0/apikeys-env)\n- [2.29.0](/cpp/docs/reference/apikeys/2.29.0/apikeys-env)\n- [2.28.0](/cpp/docs/reference/apikeys/2.28.0/apikeys-env)\n- [2.27.0](/cpp/docs/reference/apikeys/2.27.0/apikeys-env)\n- [2.26.0](/cpp/docs/reference/apikeys/2.26.0/apikeys-env)\n- [2.25.1](/cpp/docs/reference/apikeys/2.25.1/apikeys-env)\n- [2.24.0](/cpp/docs/reference/apikeys/2.24.0/apikeys-env)\n- [2.23.0](/cpp/docs/reference/apikeys/2.23.0/apikeys-env)\n- [2.22.1](/cpp/docs/reference/apikeys/2.22.1/apikeys-env)\n- [2.21.0](/cpp/docs/reference/apikeys/2.21.0/apikeys-env)\n- [2.20.0](/cpp/docs/reference/apikeys/2.20.0/apikeys-env)\n- [2.19.0](/cpp/docs/reference/apikeys/2.19.0/apikeys-env)\n- [2.18.0](/cpp/docs/reference/apikeys/2.18.0/apikeys-env)\n- [2.17.0](/cpp/docs/reference/apikeys/2.17.0/apikeys-env)\n- [2.16.0](/cpp/docs/reference/apikeys/2.16.0/apikeys-env)\n- [2.15.1](/cpp/docs/reference/apikeys/2.15.1/apikeys-env)\n- [2.14.0](/cpp/docs/reference/apikeys/2.14.0/apikeys-env)\n- [2.13.0](/cpp/docs/reference/apikeys/2.13.0/apikeys-env)\n- [2.12.0](/cpp/docs/reference/apikeys/2.12.0/apikeys-env)\n- [2.11.0](/cpp/docs/reference/apikeys/2.11.0/apikeys-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_API_KEYS_ENDPOINT=...` overrides the `EndpointOption` (which defaults to \"apikeys.googleapis.com\") used by `MakeApiKeysConnection()`.\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."]]
