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 the EndpointOption (which defaults to "apikeys.googleapis.com") used by MakeApiKeysConnection().
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.
See Also
google::cloud::TracingComponentsOptionGOOGLE_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"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["\u003cp\u003eThis document provides version-specific documentation for the C++ API Keys library, ranging from version 2.11.0 up to the latest release candidate 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eEnvironment variables can be used to configure the library's behavior, especially useful for troubleshooting, and can be overridden with functions within the code.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eGOOGLE_CLOUD_CPP_API_KEYS_ENDPOINT\u003c/code\u003e variable overrides the default endpoint for the \u003ccode\u003eMakeApiKeysConnection()\u003c/code\u003e function, allowing for custom endpoint configurations.\u003c/p\u003e\n"],["\u003cp\u003eTracing can be enabled for gRPC calls using \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc\u003c/code\u003e, and \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG\u003c/code\u003e to output on the console, along with the option to modify gRPC tracing behavior with the \u003ccode\u003eGOOGLE_CLOUD_CPP_TRACING_OPTIONS\u003c/code\u003e variable.\u003c/p\u003e\n"],["\u003cp\u003eSetting \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG=yes\u003c/code\u003e turns on logging within the library, which otherwise does not have a backend to print information to.\u003c/p\u003e\n"]]],[],null,["Version 2.13.0keyboard_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::TracingComponentsOption`](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1TracingComponentsOption.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."]]
