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::accesscontextmanager_v1::AccessContextManagerClient(
google::cloud::accesscontextmanager_v1::
MakeAccessContextManagerConnection(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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 numerous other versions, including stable releases, listed down to 2.11.0, all within the context of the accesscontextmanager and authentication override.\u003c/p\u003e\n"],["\u003cp\u003eClient libraries typically use Application Default Credentials for authentication, but this can be overridden if necessary, utilizing the UnifiedCredentialsOption.\u003c/p\u003e\n"],["\u003cp\u003eYou can explicitly load a service account key file to override the default credentials, as demonstrated in the provided code example, which sets up the AccessContextManagerClient with specific credentials.\u003c/p\u003e\n"],["\u003cp\u003eThe provided documentation links to guides on authentication components, for more information on the creation of \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects, and to best practices for managing service account keys, to improve security.\u003c/p\u003e\n"]]],[],null,[]]
