Re: [PATCH] Retry HTTP requests on SSL connect failures

> From: "Shawn O. Pearce" <spearce@spearce.org>
> 
> When libcurl fails to connect to an SSL server always retry the
> request once. Since the connection failed before the HTTP headers
> can be sent, no data has exchanged hands, so the remote side has
> not learned of the request and will not perform it twice.
> 
> In the wild we have seen git-remote-https fail to connect to
> some load-balanced SSL servers sporadically, while modern popular
> browsers (e.g. Firefox and Chromium) have no trouble with the same
> server pool.
> 
> Lets assume the site operators (Hi Google!) have a clue and are
> doing everything they already can to ensure secure, successful
> SSL connections from a wide range of HTTP clients. Implementing a
> single level of retry in the client can make it more robust against
> transient failure modes.

> +	for (attempts = 0; attempts < 2; attempts++) {
> +		if (start_active_slot(slot)) {
> +			run_active_slot(slot);
> +			if (slot->results->curl_result == CURLE_SSL_CONNECT_ERROR)
> +				continue;
> +			ret = handle_curl_result(slot);
> +		} else {
> +			error("Unable to start HTTP request for %s", url);
> +			ret = HTTP_START_FAILED;
> +		}
> +		break;

> diff --git a/remote-curl.c b/remote-curl.c
> index a269608..04a379c 100644
> --- a/remote-curl.c
> +++ b/remote-curl.c
> @@ -353,6 +353,8 @@ static int run_slot(struct active_request_slot *slot)
>  
>  	slot->results = &results;
>  	slot->curl_result = curl_easy_perform(slot->curl);
> +	if (slot->curl_result == CURLE_SSL_CONNECT_ERROR)
> +		slot->curl_result = curl_easy_perform(slot->curl);
>  	finish_active_slot(slot);