FR : exposing Retry-After header

[bulletblp4]

As per the documentation, seems like we have to honor the retry after header. But the golang sdk doesn't seem to be exposing it.

• Firebase SDK version: v3.13.0

[hiranya911]

SDK automatically does that so no additional handling is necessary. But if you really wish to access the headers, the v4 SDK provides the necessary APIs:

https://pkg.go.dev/firebase.google.com/go/v4/errorutils?tab=doc#HTTPResponse
https://firebase.google.com/docs/reference/admin/error-handling#accessing-the-http-response

[bulletblp4]

Thanks!
I havent explored the code base, but as per the docmentations

the SDK will respect that when retrying as long as the specified wait duration is not very long

How long is long here. I am asking cause a while ago we encountered a case where gcm/fcm was down for an hour or more. And our queues were stacked up with thousands of messages. Will SDK handle that case aswell ?

[hiranya911]

SDK retires are intended to help recover from transient network and backend errors that are short-lived (in the order of seconds). Therefore the SDK does not retry if the backend server sends an error with Retry-After set to a duration longer than 2 minutes.

firebase-admin-go/internal/http_client.go

Lines 69 to 89 in cef91ac

	// WithDefaultRetryConfig creates a new HTTPClient using the provided client and the default
	// RetryConfig.
	//
	// The default RetryConfig retries requests on all low-level network errors as well as on HTTP
	// InternalServerError (500) and ServiceUnavailable (503) errors. Repeatedly failing requests are
	// retried up to 4 times with exponential backoff. Retry delay is never longer than 2 minutes.
	func WithDefaultRetryConfig(hc *http.Client) *HTTPClient {
	twoMinutes := time.Duration(2) * time.Minute
	return &HTTPClient{
	Client: hc,
	RetryConfig: &RetryConfig{
	MaxRetries: 4,
	CheckForRetry: retryNetworkAndHTTPErrors(
	http.StatusInternalServerError,
	http.StatusServiceUnavailable,
	),
	ExpBackoffFactor: 0.5,
	MaxDelay: &twoMinutes,
	},
	}
	}