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_RECOMMENDER_ENDPOINT=...overrides theEndpointOption(which defaults to "recommender.googleapis.com") used byMakeRecommenderConnection().
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::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"]],[["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 webpage provides documentation for the Recommender library, with version 2.37.0-rc being the latest release candidate, and a list of previous versions available for reference, ranging from 2.11.0 to 2.36.0.\u003c/p\u003e\n"],["\u003cp\u003eThe library's behavior can be configured through various environment variables, which are particularly useful for troubleshooting.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eGOOGLE_CLOUD_CPP_RECOMMENDER_ENDPOINT\u003c/code\u003e environment variable can be used to override the default endpoint used by the \u003ccode\u003eMakeRecommenderConnection()\u003c/code\u003e function.\u003c/p\u003e\n"],["\u003cp\u003eTracing for gRPC calls can be enabled using the \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc\u003c/code\u003e environment variable, allowing detailed monitoring of gRPC requests and responses.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG=yes\u003c/code\u003e environment variable enables logging within the library, directing output to the program's console if no custom logging backend is configured.\u003c/p\u003e\n"]]],[],null,["Version 2.14.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/recommender/latest/recommender-env)\n- [2.41.0](/cpp/docs/reference/recommender/2.41.0/recommender-env)\n- [2.40.0](/cpp/docs/reference/recommender/2.40.0/recommender-env)\n- [2.39.0](/cpp/docs/reference/recommender/2.39.0/recommender-env)\n- [2.38.0](/cpp/docs/reference/recommender/2.38.0/recommender-env)\n- [2.37.0](/cpp/docs/reference/recommender/2.37.0/recommender-env)\n- [2.36.0](/cpp/docs/reference/recommender/2.36.0/recommender-env)\n- [2.35.0](/cpp/docs/reference/recommender/2.35.0/recommender-env)\n- [2.34.0](/cpp/docs/reference/recommender/2.34.0/recommender-env)\n- [2.33.0](/cpp/docs/reference/recommender/2.33.0/recommender-env)\n- [2.32.0](/cpp/docs/reference/recommender/2.32.0/recommender-env)\n- [2.31.0](/cpp/docs/reference/recommender/2.31.0/recommender-env)\n- [2.30.0](/cpp/docs/reference/recommender/2.30.0/recommender-env)\n- [2.29.0](/cpp/docs/reference/recommender/2.29.0/recommender-env)\n- [2.28.0](/cpp/docs/reference/recommender/2.28.0/recommender-env)\n- [2.27.0](/cpp/docs/reference/recommender/2.27.0/recommender-env)\n- [2.26.0](/cpp/docs/reference/recommender/2.26.0/recommender-env)\n- [2.25.1](/cpp/docs/reference/recommender/2.25.1/recommender-env)\n- [2.24.0](/cpp/docs/reference/recommender/2.24.0/recommender-env)\n- [2.23.0](/cpp/docs/reference/recommender/2.23.0/recommender-env)\n- [2.22.1](/cpp/docs/reference/recommender/2.22.1/recommender-env)\n- [2.21.0](/cpp/docs/reference/recommender/2.21.0/recommender-env)\n- [2.20.0](/cpp/docs/reference/recommender/2.20.0/recommender-env)\n- [2.19.0](/cpp/docs/reference/recommender/2.19.0/recommender-env)\n- [2.18.0](/cpp/docs/reference/recommender/2.18.0/recommender-env)\n- [2.17.0](/cpp/docs/reference/recommender/2.17.0/recommender-env)\n- [2.16.0](/cpp/docs/reference/recommender/2.16.0/recommender-env)\n- [2.15.1](/cpp/docs/reference/recommender/2.15.1/recommender-env)\n- [2.14.0](/cpp/docs/reference/recommender/2.14.0/recommender-env)\n- [2.13.0](/cpp/docs/reference/recommender/2.13.0/recommender-env)\n- [2.12.0](/cpp/docs/reference/recommender/2.12.0/recommender-env)\n- [2.11.0](/cpp/docs/reference/recommender/2.11.0/recommender-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_RECOMMENDER_ENDPOINT=...` overrides the `EndpointOption` (which defaults to \"recommender.googleapis.com\") used by `MakeRecommenderConnection()`.\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."]]
