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::containeranalysis_v1::ContainerAnalysisClient(
google::cloud::containeranalysis_v1::MakeContainerAnalysisConnection(
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"]],[["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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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\u003eThis document details how to override the default authentication credentials for Google Cloud services using the C++ client libraries, focusing on the \u003ccode\u003eUnifiedCredentialsOption\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe latest available version is \u003ccode\u003e2.37.0-rc\u003c/code\u003e, and a range of previous versions from \u003ccode\u003e2.36.0\u003c/code\u003e down to \u003ccode\u003e2.11.0\u003c/code\u003e are also accessible, all pertaining to overriding the authentication.\u003c/p\u003e\n"],["\u003cp\u003eThe example provided demonstrates explicitly loading a service account key file to override default credentials, and offers additional links for \u003ccode\u003econtaineranalysis_v1::ContainerAnalysisClient\u003c/code\u003e and \u003ccode\u003econtaineranalysis_v1::GrafeasClient\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eFor more information on managing service account keys, users are encouraged to read the "Best practices for managing service account keys" guide, as well as the Authentication Components section for creating \u003ccode\u003egoogle::cloud::Credentials\u003c/code\u003e objects.\u003c/p\u003e\n"]]],[],null,[]]
