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::logging_v2::ConfigServiceV2Client(
google::cloud::logging_v2::MakeConfigServiceV2Connection(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 document provides a list of versioned documentation for overriding authentication credentials in Google Cloud C++ client libraries, starting from version 2.11.0 and going up to the latest release candidate 2.37.0-rc."],["The default authentication method for these libraries uses Application Default Credentials, but this can be overridden using the `UnifiedCredentialsOption`."],["You can explicitly load a service account key file to override default credentials, as demonstrated in the provided code example, which loads a service account key file and uses it to set the authentication credentials."],["Examples for overriding authentication are provided for `ConfigServiceV2Client`, `LoggingServiceV2Client`, and `MetricsServiceV2Client`."],["For more information on creating `google::cloud::Credentials` objects, you can consult the Authentication Components documentation."]]],[]]