Authenticate for Google Cloud PubSub using parameters from a config file in c#.net - google-cloud-platform

Question

I am following this sample in attempt to publish messages in PubSub from a c#.net app on a windows server. As expected it throws auth exception on:
PublisherClient publisher = PublisherClient.Create();
Most of my code base connects to GCS and BigQuery using their respective services, sample below:
private StorageService GetStorageService()
{
X509Certificate2 certificate = new X509Certificate2(certificateFile, "notasecret", X509KeyStorageFlags.Exportable);
ServiceAccountCredential credential = new ServiceAccountCredential(
new ServiceAccountCredential.Initializer(serviceAccountEmail)
{
Scopes = new[] { StorageService.Scope.DevstorageFullControl }
}.FromCertificate(certificate));
return new StorageService(new BaseClientService.Initializer()
{
HttpClientInitializer = credential,
ApplicationName = projectNumber,
});
}
I just pass certificateFile, serviceAccountEmail from a config file as parameters. Is there anyway to Auth similarly for PubSub?

Answer 1

Yes, it's possible, and you're looking in the right repo for samples. I notice the QuickStart directory is missing a README.md. I'll add one shortly.
To get this line of code to work:
PublisherClient publisher = PublisherClient.Create();
Set the environment variable GOOGLE_APPLICATION_CREDENTIALS to the path of a json service account credentials file. Details are in step 3 of the root README:
https://github.com/GoogleCloudPlatform/dotnet-docs-samples/blob/master/README.md
If your environment requires you to manually specify the path to a credential file, the code looks like this:
GoogleCredential googleCredential = null;
using (var jsonStream = new FileStream(jsonPath, FileMode.Open,
FileAccess.Read, FileShare.Read))
{
googleCredential = GoogleCredential.FromStream(jsonStream)
.CreateScoped(PublisherClient.DefaultScopes);
}
Channel channel = new Channel(PublisherClient.DefaultEndpoint.Host,
PublisherClient.DefaultEndpoint.Port,
googleCredential.ToChannelCredentials());
PublisherClient publisher = PublisherClient.Create(channel);
I reported issue https://github.com/GoogleCloudPlatform/google-cloud-dotnet/issues/1398 to make this common task simpler.