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_SERVICE_USAGE_ENDPOINT=... overrides the EndpointOption (which defaults to "serviceusage.googleapis.com") used by MakeServiceUsageConnection().
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::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"]],[["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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 details various versions of the Service Usage C++ library, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eThe environment variable \u003ccode\u003eGOOGLE_CLOUD_CPP_SERVICE_USAGE_ENDPOINT\u003c/code\u003e allows users to override the default endpoint used by the \u003ccode\u003eMakeServiceUsageConnection()\u003c/code\u003e function.\u003c/p\u003e\n"],["\u003cp\u003eUsers can enable detailed tracing for gRPC calls using the \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc\u003c/code\u003e environment variable, which requires \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG\u003c/code\u003e to be set for console output.\u003c/p\u003e\n"],["\u003cp\u003eThe library's logging can be enabled by setting \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG=yes\u003c/code\u003e, which activates the backend to output the library's logs.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eGOOGLE_CLOUD_PROJECT\u003c/code\u003e can be used in examples and integration tests to set a project but will have no effect in the library itself.\u003c/p\u003e\n"]]],[],null,[]]
