Creating new cache doesn't return error even if storage key is wrong

[renxinhe]

I tried testing Azure storage authentication using the following code:

autocertCacheAzureStorageAccountKey = "YmFkY3JlZGVudGlhbA==" // base64 encoded string "badcredential"

azureCertCache, err := azcertcache.New(
        autocertCacheAzureStorageAccountName,
	autocertCacheAzureStorageAccountKey,
	autocertCacheAzureStorageContainerName,
)

I encoded a purposely wrong account key in base64 and passed it into autocertCacheAzureStorageAccountKey. This should have returned an authentication error, however, err is returned as nil.

During runtime, when the server receives its first HTTPS request, it would fail to obtain the certificate from the Blob Storage.

https server started on [::]:443
echo: http: TLS handshake error from <REDACTED>:56440: -> github.com/Azure/azure-storage-blob-go/azblob.NewResponseError, /home/os/go/pkg/mod/github.com/!azure/azure-storage-blob-go@v0.0.0-20190123011202-457680cc0804/azblob/zz_generated_response_error.go:29
===== RESPONSE ERROR (ServiceCode=AuthenticationFailed) =====
Description=Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature.
RequestId:<REDACTED>
Time:2022-06-01T19:27:41.4488737Z, Details:
   AuthenticationErrorDetail: The MAC signature found in the HTTP request 'GVFuzxZ2UEFZSGUQt8HUt+0iNHDN6K007YKFKcZkbWc=' is not the same as any computed signature. Server used following string to sign: 'GET
x-ms-client-request-id:42dbaddb-0344-4092-5034-06bc350961d7
x-ms-date:Wed, 01 Jun 2022 19:27:41 GMT
x-ms-version:2018-03-28
/<REDACTED_azure_storage_name>/<REDACTED_container_name>/<REDACTED_dns_cname>
timeout:61'.
   Code: AuthenticationFailed
   GET https://<REDACTED_azure_storage_name>.blob.core.windows.net/<REDACTED_container_name>/<REDACTED_dns_cname>?timeout=61
   Authorization: REDACTED
   User-Agent: [Azure-Storage/0.5 (go1.17.4; linux)]
   X-Ms-Client-Request-Id: [42dbaddb-0344-4092-5034-06bc350961d7]
   X-Ms-Date: [Wed, 01 Jun 2022 19:27:41 GMT]
   X-Ms-Version: [2018-03-28]
   --------------------------------------------------------------------------------
   RESPONSE Status: 403 Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature.
   Content-Length: [783]
   Content-Type: [application/xml]
   Date: [Wed, 01 Jun 2022 19:27:40 GMT]
   Server: [Microsoft-HTTPAPI/2.0]
   X-Ms-Error-Code: [AuthenticationFailed]
   X-Ms-Request-Id: [93dbd2ed-101e-0036-3aed-75ec6e000000]

I think azcertcache.New should return an error if the storage credential is wrong, instead of failing when the first HTTPS request comes in.

[goenning]

I’m no longer using this package, but you send a PR I can merge it 👍

[renxinhe]

@goenning I submitted a PR. Please take a look when you have time. Thanks!

[goenning]

Thank you!