On Tue, 17 Nov 2020, Eran Kornblau wrote:
Hi,
This patch adds 2 options to http:
- reconnect_on_status - a list of http status codes that should be retried. the
list can contain explicit status codes or the strings 4xx/5xx.
- reconnect_on_err - reconnects on arbitrary errors during connect, e.g.
ECONNRESET/ETIMEDOUT.
The retry employs the same exponential backoff logic as the existing
reconnect/reconnect_at_eof flags.
Related tickets:
https://trac.ffmpeg.org/ticket/6066
https://trac.ffmpeg.org/ticket/7768
From f412ca316f26f8c52d9763a33703ab06134feb37 Mon Sep 17 00:00:00 2001
From: erankor <eran.kornb...@kaltura.com>
Date: Sun, 25 Oct 2020 15:25:13 +0200
Subject: [PATCH] http: support retry on connection error
added 2 new options:
- reconnect_on_status - a list of http status codes that should be
retried. the list can contain explicit status codes / the strings
4xx/5xx.
Maybe better name this option reconnect_on_http_error. Also this is a
flags-like option, so use AV_OPT_TYPE_FLAGS with 4xx and 5xx as flags.
- reconnect_on_err - reconnects on arbitrary errors during connect, e.g.
ECONNRESET/ETIMEDOUT
Maybe reconnect_on_network_error better reflects that this reconnects on
underlying protocol (TCP/TLS) error.
Anyhow, the new options should be added to docs/protocols.texi.
the retry employs the same exponential backoff logic as the existing
reconnect/reconnect_at_eof flags.
related tickets:
https://trac.ffmpeg.org/ticket/6066
https://trac.ffmpeg.org/ticket/7768
---
libavformat/http.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 60 insertions(+), 2 deletions(-)
diff --git a/libavformat/http.c b/libavformat/http.c
index 3d25d652d3..ea14ef0c47 100644
--- a/libavformat/http.c
+++ b/libavformat/http.c
@@ -119,8 +119,10 @@ typedef struct HTTPContext {
char *method;
int reconnect;
int reconnect_at_eof;
+ int reconnect_on_err;
int reconnect_streamed;
int reconnect_delay_max;
+ char *reconnect_on_status;
int listen;
char *resource;
int reply_code;
@@ -164,6 +166,8 @@ static const AVOption options[] = {
{ "method", "Override the HTTP method or set the expected HTTP method from a
client", OFFSET(method), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
{ "reconnect", "auto reconnect after disconnect before EOF",
OFFSET(reconnect), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D },
{ "reconnect_at_eof", "auto reconnect at EOF", OFFSET(reconnect_at_eof),
AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D },
+ { "reconnect_on_err", "auto reconnect in case of tcp/tls error during
connect", OFFSET(reconnect_on_err), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D },
+ { "reconnect_on_status", "list of http status codes to reconnect on. the list
can include specific status codes / 4xx / 5xx", OFFSET(reconnect_on_status),
AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D },
AV_OPT_TYPE_FLAGS, as I explained above.
{ "reconnect_streamed", "auto reconnect streamed / non seekable streams",
OFFSET(reconnect_streamed), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D },
{ "reconnect_delay_max", "max reconnect delay in seconds after which to give
up", OFFSET(reconnect_delay_max), AV_OPT_TYPE_INT, { .i64 = 120 }, 0, UINT_MAX/1000/1000, D },
{ "listen", "listen on HTTP", OFFSET(listen), AV_OPT_TYPE_INT, { .i64 = 0
}, 0, 2, D | E },
@@ -258,21 +262,75 @@ static int http_open_cnx_internal(URLContext *h,
AVDictionary **options)
return location_changed;
}
+static int http_should_reconnect(HTTPContext *s, int err)
+{
+ const char *status_group;
+ char http_code[4];
+
+ switch (err) {
+ case AVERROR_HTTP_BAD_REQUEST:
+ case AVERROR_HTTP_UNAUTHORIZED:
+ case AVERROR_HTTP_FORBIDDEN:
+ case AVERROR_HTTP_NOT_FOUND:
+ case AVERROR_HTTP_OTHER_4XX:
+ status_group = "4xx";
+ break;
+
+ case AVERROR_HTTP_SERVER_ERROR:
+ status_group = "5xx";
+ break;
+
+ default:
+ return s->reconnect_on_err;
+ }
+
+ if (!s->reconnect_on_status) {
+ return 0;
+ }
+
+ if (av_match_list(status_group, s->reconnect_on_status, ',') > 0) {
+ return 1;
+ }
+
+ snprintf(http_code, sizeof(http_code), "%d", s->http_code);
+
+ return av_match_list(http_code, s->reconnect_on_status, ',') > 0;
+}
+
/* return non zero if error */
static int http_open_cnx(URLContext *h, AVDictionary **options)
{
HTTPAuthType cur_auth_type, cur_proxy_auth_type;
HTTPContext *s = h->priv_data;
int location_changed, attempts = 0, redirects = 0;
+ int reconnect_delay = 0;
+ uint64_t off;
+
redo:
av_dict_copy(options, s->chained_options, 0);
cur_auth_type = s->auth_state.auth_type;
cur_proxy_auth_type = s->auth_state.auth_type;
+ off = s->off;
location_changed = http_open_cnx_internal(h, options);
Are you sure you get AVERROR_HTTP_* here? Also if you follow the code
there is special handling of 401/407, that should be done first before
your checks, no?
- if (location_changed < 0)
- goto fail;
+ if (location_changed < 0) {
+ if (!http_should_reconnect(s, location_changed) ||
+ reconnect_delay > s->reconnect_delay_max)
+ goto fail;
+
+ av_log(h, AV_LOG_WARNING, "Will reconnect at %"PRIu64" in %d
second(s).\n", off, reconnect_delay);
+ location_changed = ff_network_sleep_interruptible(1000U * 1000 *
reconnect_delay, &h->interrupt_callback);
+ if (location_changed != AVERROR(ETIMEDOUT))
+ goto fail;
+ reconnect_delay = 1 + 2 * reconnect_delay;
+
+ /* restore the offset (http_connect resets it) */
+ s->off = off;
+
+ ffurl_closep(&s->hd);
+ goto redo;
+ }
attempts++;
if (s->http_code == 401) {
Another comment is that if you want to reconnect based on errors
classified as 4xx or 5xx, then probably you should revisit
ff_http_averror(400, xxx) calls and check if they are indeed caused by
client behaviour. Because if the server is violating the protocol, then
they should be ff_http_averror(500, xxx) IMHO.
Regards,
Marton
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