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::functions_v1::CloudFunctionsServiceClient(
google::cloud::functions_v1::MakeCloudFunctionsServiceConnection(
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 2025-03-14 UTC."],[[["This page documents how to override the default authentication credentials used by Google Cloud client libraries, which typically rely on Application Default Credentials."],["You can override default credentials by utilizing the `UnifiedCredentialsOption` and providing explicit credentials, such as those from a service account key file."],["The provided example demonstrates loading credentials from a service account key file using `MakeServiceAccountCredentials` within a C++ context."],["Examples for `CloudFunctionsServiceClient` and `FunctionServiceClient` are linked, offering specific guidance for those client classes in versions 2.31.0 of the reference documentation."],["The page references best practices for managing service account keys and the Authentication Components for more details on credential management within Google Cloud."]]],[]]
