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::serviceusage_v1::ServiceUsageClient(
google::cloud::serviceusage_v1::MakeServiceUsageConnection(options));
}
[[["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 numerous other versions, from 2.36.0 down to 2.11.0, also accessible via the provided links."],["The client libraries typically use Application Default Credentials for Google Cloud Service authentication, but this default can be overridden when necessary."],["You can override the default credentials by providing the UnifiedCredentialsOption, as demonstrated by an example showing how to explicitly load a service account key file."],["The provided example, while simple, represents only one way to manage credentials, and users should refer to the \"Best practices for managing service account keys\" guide for more information."],["More details about the creation of [`google::cloud::Credentials`](https://cloud.google.com/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1Credentials.html) objects can be found in the Authentication Components documentation."]]],[]]
