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::vmmigration_v1::VmMigrationClient(
google::cloud::vmmigration_v1::MakeVmMigrationConnection(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."],[[["This webpage provides documentation for various versions of the vmmigration library, ranging from version 2.11.0 up to the latest release candidate 2.37.0-rc."],["The primary content focuses on how to override the default authentication credentials used by client libraries when interacting with Google Cloud Services."],["Overriding the default credentials can be accomplished by utilizing the `UnifiedCredentialsOption` and providing a service account key file for authentication."],["The example provided demonstrates how to load a service account key file, though it is noted to consult the \"Best practices for managing service account keys\" guide for more comprehensive information."],["Additional details on authentication components and creating `google::cloud::Credentials` objects can be found in the \"Authentication Components\" section, which links to further information."]]],[]]