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_REACHABILITY_SERVICE_ENDPOINT=...overrides theEndpointOption(which defaults to "networkmanagement.googleapis.com") used byMakeReachabilityServiceConnection().
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 document outlines environment variables and settings for configuring the behavior of the C++ network management library, particularly when troubleshooting.\u003c/p\u003e\n"],["\u003cp\u003eThe latest release candidate version is 2.37.0-rc, and there are many previous versions of the C++ network management library readily available for download and use, such as version 2.36.0, 2.35.0 and many more all the way to 2.11.0.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eGOOGLE_CLOUD_CPP_REACHABILITY_SERVICE_ENDPOINT\u003c/code\u003e can be set to override the default endpoint used by \u003ccode\u003eMakeReachabilityServiceConnection()\u003c/code\u003e, allowing for custom endpoint configurations.\u003c/p\u003e\n"],["\u003cp\u003eYou can use \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING\u003c/code\u003e to enable tracing for gRPC calls, which outputs gRPC requests and responses, and \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG\u003c/code\u003e to produce output to the console, allowing logging to occur.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eGOOGLE_CLOUD_PROJECT\u003c/code\u003e can be set to define the GCP project when testing, but is not used by the library itself, and is only used for example and testing purposes.\u003c/p\u003e\n"]]],[],null,["Version 2.11.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/networkmanagement/latest/networkmanagement-env)\n- [2.41.0](/cpp/docs/reference/networkmanagement/2.41.0/networkmanagement-env)\n- [2.40.0](/cpp/docs/reference/networkmanagement/2.40.0/networkmanagement-env)\n- [2.39.0](/cpp/docs/reference/networkmanagement/2.39.0/networkmanagement-env)\n- [2.38.0](/cpp/docs/reference/networkmanagement/2.38.0/networkmanagement-env)\n- [2.37.0](/cpp/docs/reference/networkmanagement/2.37.0/networkmanagement-env)\n- [2.36.0](/cpp/docs/reference/networkmanagement/2.36.0/networkmanagement-env)\n- [2.35.0](/cpp/docs/reference/networkmanagement/2.35.0/networkmanagement-env)\n- [2.34.0](/cpp/docs/reference/networkmanagement/2.34.0/networkmanagement-env)\n- [2.33.0](/cpp/docs/reference/networkmanagement/2.33.0/networkmanagement-env)\n- [2.32.0](/cpp/docs/reference/networkmanagement/2.32.0/networkmanagement-env)\n- [2.31.0](/cpp/docs/reference/networkmanagement/2.31.0/networkmanagement-env)\n- [2.30.0](/cpp/docs/reference/networkmanagement/2.30.0/networkmanagement-env)\n- [2.29.0](/cpp/docs/reference/networkmanagement/2.29.0/networkmanagement-env)\n- [2.28.0](/cpp/docs/reference/networkmanagement/2.28.0/networkmanagement-env)\n- [2.27.0](/cpp/docs/reference/networkmanagement/2.27.0/networkmanagement-env)\n- [2.26.0](/cpp/docs/reference/networkmanagement/2.26.0/networkmanagement-env)\n- [2.25.1](/cpp/docs/reference/networkmanagement/2.25.1/networkmanagement-env)\n- [2.24.0](/cpp/docs/reference/networkmanagement/2.24.0/networkmanagement-env)\n- [2.23.0](/cpp/docs/reference/networkmanagement/2.23.0/networkmanagement-env)\n- [2.22.1](/cpp/docs/reference/networkmanagement/2.22.1/networkmanagement-env)\n- [2.21.0](/cpp/docs/reference/networkmanagement/2.21.0/networkmanagement-env)\n- [2.20.0](/cpp/docs/reference/networkmanagement/2.20.0/networkmanagement-env)\n- [2.19.0](/cpp/docs/reference/networkmanagement/2.19.0/networkmanagement-env)\n- [2.18.0](/cpp/docs/reference/networkmanagement/2.18.0/networkmanagement-env)\n- [2.17.0](/cpp/docs/reference/networkmanagement/2.17.0/networkmanagement-env)\n- [2.16.0](/cpp/docs/reference/networkmanagement/2.16.0/networkmanagement-env)\n- [2.15.1](/cpp/docs/reference/networkmanagement/2.15.1/networkmanagement-env)\n- [2.14.0](/cpp/docs/reference/networkmanagement/2.14.0/networkmanagement-env)\n- [2.13.0](/cpp/docs/reference/networkmanagement/2.13.0/networkmanagement-env)\n- [2.12.0](/cpp/docs/reference/networkmanagement/2.12.0/networkmanagement-env)\n- [2.11.0](/cpp/docs/reference/networkmanagement/2.11.0/networkmanagement-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_REACHABILITY_SERVICE_ENDPOINT=...` overrides the `EndpointOption` (which defaults to \"networkmanagement.googleapis.com\") used by `MakeReachabilityServiceConnection()`.\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."]]
