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_TPU_ENDPOINT=... overrides the EndpointOption (which defaults to "tpu.googleapis.com") used by MakeTpuConnection().
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"]],[["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 2025-03-14 UTC."],[[["This page provides documentation for various versions of the C++ TPU library, ranging from version 2.11.0 up to the latest release candidate, 2.37.0-rc."],["Environment variables can be used to configure the library's behavior, especially useful for troubleshooting, and there are also equivalent in code functions."],["The `GOOGLE_CLOUD_CPP_TPU_ENDPOINT` environment variable can override the default endpoint used by the `MakeTpuConnection()` function."],["Tracing for gRPC calls can be enabled using `GOOGLE_CLOUD_CPP_ENABLE_TRACING`, and logging can be turned on with `GOOGLE_CLOUD_CPP_ENABLE_CLOG`, allowing developers to track request and response interactions."],["While it is commonly used in tests and examples, the `GOOGLE_CLOUD_PROJECT` environment variable does not have any effect on the behavior of the C++ library."]]],[]]
