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::securesourcemanager_v1::SecureSourceManagerClient(
google::cloud::securesourcemanager_v1::
MakeSecureSourceManagerConnection(options));
}
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["\u003cp\u003eThe latest version available is 2.37.0-rc, with multiple preceding versions, ranging from 2.36.0 down to 2.18.0, also available.\u003c/p\u003e\n"],["\u003cp\u003eThe client libraries primarily utilize Application Default Credentials for Google Cloud Services authentication, although this can be overridden.\u003c/p\u003e\n"],["\u003cp\u003eAuthentication can be overridden by using the UnifiedCredentialsOption, which is exemplified by loading a service account key file.\u003c/p\u003e\n"],["\u003cp\u003eThe code provided is a simplified example of overriding default authentication, and it is recommended to refer to best practices for service account key management.\u003c/p\u003e\n"],["\u003cp\u003eFor additional information on creating Credentials objects, the Authentication Components documentation is provided.\u003c/p\u003e\n"]]],[],null,[]]
