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::datastream_v1::DatastreamClient(
google::cloud::datastream_v1::MakeDatastreamConnection(options));
}
[[["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."],[[["The latest version available is 2.37.0-rc, with numerous other versions, starting at 2.36.0 and going all the way to 2.11.0, available for selection."],["By default, client libraries utilize Application Default Credentials for authenticating with Google Cloud Services."],["You can override the default authentication credentials by providing the `UnifiedCredentialsOption`, allowing for custom authentication configurations."],["Service account key files can be loaded explicitly to override default credentials, as demonstrated in the provided code example using the `MakeServiceAccountCredentials` function."],["For detailed information about creating `google::cloud::Credentials` objects, refer to the Authentication Components section in the documentation."]]],[]]