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_SIMULATOR_ENDPOINT=...overrides theEndpointOption(which defaults to "policysimulator.googleapis.com") used byMakeSimulatorConnection().
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\u003eThe latest release candidate version for the Policy Simulator environment is 2.37.0-rc, and the most recent stable version available is 2.36.0.\u003c/p\u003e\n"],["\u003cp\u003eA comprehensive list of versions, ranging from 2.15.1 to 2.37.0-rc, provides links to the documentation for each specific release of the Policy Simulator environment.\u003c/p\u003e\n"],["\u003cp\u003eEnvironment variables like \u003ccode\u003eGOOGLE_CLOUD_CPP_SIMULATOR_ENDPOINT\u003c/code\u003e can override default settings, such as the endpoint for the Policy Simulator connection.\u003c/p\u003e\n"],["\u003cp\u003eLogging and tracing for gRPC calls can be enabled using \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING\u003c/code\u003e and \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG\u003c/code\u003e, with options to customize the output format and content via \u003ccode\u003eGOOGLE_CLOUD_CPP_TRACING_OPTIONS\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eWhile \u003ccode\u003eGOOGLE_CLOUD_PROJECT\u003c/code\u003e can set the default GCP project in examples and tests, it does not impact the behavior of the Policy Simulator library itself.\u003c/p\u003e\n"]]],[],null,["Version 2.27.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/policysimulator/latest/policysimulator-env)\n- [2.41.0](/cpp/docs/reference/policysimulator/2.41.0/policysimulator-env)\n- [2.40.0](/cpp/docs/reference/policysimulator/2.40.0/policysimulator-env)\n- [2.39.0](/cpp/docs/reference/policysimulator/2.39.0/policysimulator-env)\n- [2.38.0](/cpp/docs/reference/policysimulator/2.38.0/policysimulator-env)\n- [2.37.0](/cpp/docs/reference/policysimulator/2.37.0/policysimulator-env)\n- [2.36.0](/cpp/docs/reference/policysimulator/2.36.0/policysimulator-env)\n- [2.35.0](/cpp/docs/reference/policysimulator/2.35.0/policysimulator-env)\n- [2.34.0](/cpp/docs/reference/policysimulator/2.34.0/policysimulator-env)\n- [2.33.0](/cpp/docs/reference/policysimulator/2.33.0/policysimulator-env)\n- [2.32.0](/cpp/docs/reference/policysimulator/2.32.0/policysimulator-env)\n- [2.31.0](/cpp/docs/reference/policysimulator/2.31.0/policysimulator-env)\n- [2.30.0](/cpp/docs/reference/policysimulator/2.30.0/policysimulator-env)\n- [2.29.0](/cpp/docs/reference/policysimulator/2.29.0/policysimulator-env)\n- [2.28.0](/cpp/docs/reference/policysimulator/2.28.0/policysimulator-env)\n- [2.27.0](/cpp/docs/reference/policysimulator/2.27.0/policysimulator-env)\n- [2.26.0](/cpp/docs/reference/policysimulator/2.26.0/policysimulator-env)\n- [2.25.1](/cpp/docs/reference/policysimulator/2.25.1/policysimulator-env)\n- [2.24.0](/cpp/docs/reference/policysimulator/2.24.0/policysimulator-env)\n- [2.23.0](/cpp/docs/reference/policysimulator/2.23.0/policysimulator-env)\n- [2.22.1](/cpp/docs/reference/policysimulator/2.22.1/policysimulator-env)\n- [2.21.0](/cpp/docs/reference/policysimulator/2.21.0/policysimulator-env)\n- [2.20.0](/cpp/docs/reference/policysimulator/2.20.0/policysimulator-env)\n- [2.19.0](/cpp/docs/reference/policysimulator/2.19.0/policysimulator-env)\n- [2.18.0](/cpp/docs/reference/policysimulator/2.18.0/policysimulator-env)\n- [2.17.0](/cpp/docs/reference/policysimulator/2.17.0/policysimulator-env)\n- [2.16.0](/cpp/docs/reference/policysimulator/2.16.0/policysimulator-env)\n- [2.15.1](/cpp/docs/reference/policysimulator/2.15.1/policysimulator-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_SIMULATOR_ENDPOINT=...` overrides the `EndpointOption` (which defaults to \"policysimulator.googleapis.com\") used by `MakeSimulatorConnection()`.\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."]]
