Unless otherwise configured, the client libraries use Application Default Credentials to authenticate with Google Cloud Services. While this works for most applications, in some cases you may need to override this default. You can do so by providing the UnifiedCredentialsOption The following example shows how to explicitly load a service account key file:
[](std::string const& keyfile) {
auto is = std::ifstream(keyfile);
is.exceptions(std::ios::badbit); // Minimal error handling in examples
auto contents = std::string(std::istreambuf_iterator<char>(is.rdbuf()), {});
auto options =
google::cloud::Options{}.set<google::cloud::UnifiedCredentialsOption>(
google::cloud::MakeServiceAccountCredentials(contents));
return google::cloud::trace_v1::TraceServiceClient(
google::cloud::trace_v1::MakeTraceServiceConnection(options));
}
Follow these links to find examples for other *Client classes:
[[["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 2025-03-21 UTC."],[[["The latest version available is 2.37.0-rc, with a comprehensive list of previous versions ranging from 2.36.0 down to 2.11.0 also provided."],["Client libraries primarily utilize Application Default Credentials for authentication with Google Cloud Services, but this can be overridden."],["You can override default authentication by using the `UnifiedCredentialsOption` and loading a service account key file."],["Examples are available for `trace_v1::TraceServiceClient` and `trace_v2::TraceServiceClient`, demonstrating how to override authentication in other client classes."],["The best practice guide for managing service account keys and the authentication components document provide further details on this subject."]]],[]]