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::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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 lists available 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\u003eEnvironment variables, such as \u003ccode\u003eGOOGLE_CLOUD_CPP_SERVICE_USAGE_ENDPOINT\u003c/code\u003e, can be used to override default library configurations like the endpoint.\u003c/p\u003e\n"],["\u003cp\u003eTracing can be enabled for gRPC calls via \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc\u003c/code\u003e, and the logging output can be sent to the console by setting \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eGOOGLE_CLOUD_CPP_TRACING_OPTIONS\u003c/code\u003e environment variable controls the formatting and behavior of gRPC tracing, including truncation of string and byte fields.\u003c/p\u003e\n"],["\u003cp\u003eWhile \u003ccode\u003eGOOGLE_CLOUD_PROJECT\u003c/code\u003e configures the GCP project in examples and tests, it does not impact the library's functionality directly.\u003c/p\u003e\n"]]],[],null,[]]
