Oops, I meant:
static int dh(void *cls, struct MHD_Connection *con, const char *url,
const char *method, const char *version,
const char *upload_data, size_t *upload_data_size, void
**con_cls) {
const char *page = "<html><body>I love MHD!</body></html>";
struct MHD_Daemon *d;
struct MHD_Response *response;
int ret;
unsigned char i;
bool quiesced;
if (NULL != *con_cls) {
*con_cls = (void *) 1;
return MHD_YES;
}
/* simulating a long processing, like hard query in a database ... */
i = 1;
while (i < 100) {
MHD_get_connection_info(con, MHD_CONNECTION_INFO_DAEMON, &d);
if (d) {
MHD_get_daemon_info(d, *MHD_DAEMON_INFO_<some option
informing that daemon was quiesced>*, &quiesced);
if (quiesced)
break;
}
sleep(1);
i++;
}
response = MHD_create_response_from_buffer(strlen(page), (void *)
page, MHD_RESPMEM_PERSISTENT);
ret = MHD_queue_response(con, MHD_HTTP_OK, response);
MHD_destroy_response(response);
return ret;
}
On Tue, Mar 28, 2017 at 1:32 PM, silvioprog <[email protected]> wrote:
> Done. The entire code is: https://pastebin.com/gNY2MwSY . I've used "curl
> http://localhost:8080; echo" to test it.
>
> Commenting the code: the locking happens at line 39 (MHD_stop_daemon(d)).
> I don't know it the stop function offer some option to force the server
> stopping, but I think we really don't need it. However, it would be nice to
> have a "MHD_DAEMON_INFO_<some option informing the daemon was quiesced>",
> so the clients could check it in their processing, e.g:
>
> ...
>
> static int dh(void *cls, struct MHD_Connection *con, const char *url, const
> char *method, const char *version,
> const char *upload_data, size_t *upload_data_size, void
> **con_cls) {
> const char *page = "<html><body>I love MHD!</body></html>";
> struct MHD_Daemon *d;
> struct MHD_Response *response;
> int ret;
> unsigned char i = 1;
> bool stoped;
> if (NULL != *con_cls) {
> *con_cls = (void *) 1;
> return MHD_YES;
> }
> /* simulating a long processing, like hard query in a database ... */
> i = 1;
> while (i < 100) {
> MHD_get_connection_info(con, MHD_CONNECTION_INFO_DAEMON, &d);
> if (d && MHD_get_daemon_info(d, *MHD_DAEMON_INFO_<some option
> informing that daemon was quiesced>*))
> break;
> sleep(1);
> i++;
> }
> response = MHD_create_response_from_buffer(strlen(page), (void *) page,
> MHD_RESPMEM_PERSISTENT);
> ret = MHD_queue_response(con, MHD_HTTP_OK, response);
> MHD_destroy_response(response);
> return ret;
> }
>
> ...
>
> It is just a idea, but I'm totally open to get new ideas. :-)
>
> Anyway, if you see that *MHD_DAEMON_INFO_<some option informing that
> daemon was quiesced>* could be an useful feature, I can try to send a
> patch implementing it, something like *MHD_DAEMON_INFO_**WAS_QUIESCED*.
>
> On Tue, Mar 28, 2017 at 12:51 PM, silvioprog <[email protected]> wrote:
>
>> Dude, thanks for fixing it, I'm going to study the changes and apply it
>> here. :-)
>>
>> I've got a situation that locks the shutdown even using this fix, but I
>> need to create a small project simulating the problem, I'm going to do it
>> now ...
>>
>> On Tue, Mar 28, 2017 at 12:08 PM, Evgeny Grin <[email protected]> wrote:
>>
>>> Fixed version of you code:
>>>
>>> bool bf_httpsrv_shutdown(struct bf_httpsrv *srv) { MHD_socket fd;
>>> uint8_t shutdown_attempts; /* Max 256. */ if (srv && srv->listening) {
>>> fd = MHD_quiesce_daemon(srv->mhd); if (fd != MHD_INVALID_SOCKET) {
>>> srv->listening = false; close(fd); if (! srv->forced_shutdown) {
>>> shutdown_attempts = 1; while (MHD_get_daemon_info(srv->mhd,
>>> MHD_DAEMON_INFO_CURRENT_CONNECTIONS)->num_connections > 0) { if
>>> (shutdown_attempts >= srv->shutdown_attempts) { /* Default
>>> srv->shutdown_attempts is 10. */ _BF_LOG("Forced server shutdown.\n");
>>> break; } shutdown_attempts++; sleep(1); } } } else _BF_LOG("Server
>>> quiesce failed.\n"); MHD_stop_daemon(srv->mhd); return true; } return
>>> false; }
>>>
>>> --
>>> Best Wishes,
>>> Evgeny Grin
>>>
>>> On 28.03.2017 4:46, silvioprog wrote:
>>> > Thanks for replying Evgeny, you and Christian always saving my day. :-)
>>> > I read and re-read your and Christian answer, and finally I found a
>>> > possible way to never lock the server at shutdown: adding an option to
>>> > exit the server after configurable attempts. It can solve the timeout
>>> > problem too, because I can't ensure that the programmer have
>>> > configured it (anyway my library will assume 15 seconds by default).
>>> > So, the code below applies your tips and implements the attempts
>>> approach:
>>> > bool bf_httpsrv_shutdown(struct bf_httpsrv *srv) { MHD_socket fd;
>>> > uint8_t shutdown_attempts; /* Max 256. */ if (srv && srv->listening) {
>>> > fd = MHD_quiesce_daemon(srv->mhd); if (fd != MHD_INVALID_SOCKET)
>>> > close(fd); else _BF_LOG("Server quiesce failed.\n"); if
>>> > (srv->forced_shutdown) { shutdown_attempts = 1; while
>>> > (MHD_get_daemon_info(srv->mhd,
>>> > MHD_DAEMON_INFO_CURRENT_CONNECTIONS)->num_connections > 0) { if
>>> > (shutdown_attempts >= srv->shutdown_attempts) { /* Default
>>> > srv->shutdown_attempts is 10. */ _BF_LOG("Forced server shutdown.\n");
>>> > exit(EINTR); } shutdown_attempts++; sleep(1); } }
>>> > MHD_stop_daemon(srv->mhd); srv->listening = false; return true; }
>>> > return false; }
>>> > Unfortunately if exit was called the MHD_stop_daemon() will be not
>>> > called, probably raising some memory leak, but current I have no idea
>>> > how it could be solved.
>>> > Feel totally free to point improvements about this new version. :-)
>>> > On Sun, Mar 26, 2017 at 5:36 PM, Evgeny Grin <[email protected]
>>> > <mailto:[email protected]>> wrote:
>>> >
>>> > On 26.03.2017 8:33, silvioprog wrote: > I found the following
>>> > related message: > >
>>> > https://lists.gnu.org/archive/html/libmicrohttpd/2014-09/ms
>>> g00012.html
>>> > <https://lists.gnu.org/archive/html/libmicrohttpd/2014-09/m
>>> sg00012.html>
>>> > > > I've used a similar logic, but with item X below, because I
>>> > need to wait > the client processing: > > 1) MHD_quiesce_daemon()
>>> > > *X) while (info.num_connections > 0) sleep(0.5s) # pseudo code*
>>> > > 2) MHD_stop_daemon() > 3) close() > > Real implementation: > >
>>> > bool bf_httpsrv_shutdown(struct bf_httpsrv *srv, bool force) { >
>>> > MHD_socket fd; > if (srv && srv->listening) { > fd
>>> > = MHD_quiesce_daemon(srv->mhd); > if (!force) >
>>> > while (MHD_get_daemon_info(srv->mhd,
>>> > MHD_DAEMON_INFO_CURRENT_CONNECTIONS)->num_connections > 0) >
>>> > usleep(1000 * 500); //TODO: allow to use external
>>> > callback > MHD_stop_daemon(srv->mhd); > if (fd !=
>>> > MHD_INVALID_SOCKET) > close(fd); >
>>> > srv->listening = false; > return true; > } >
>>> > return false; > } > > > Calling it with bf_httpsrv_shutdown(srv,
>>> > false) the server stops waiting > for clients processing. > > So,
>>> > what do you think about the logic above? Should it be improved?! >
>>> > > Thanks in advance for any suggestions! If you don't check
>>> > returned value from MHD_quiesce_daemon(), you may later found that
>>> > you didn't quiesced daemon, so move check right after
>>> > MHD_quiesce_daemon() and added error handling. If you didn't set
>>> > connection timeout, connection may live indefinitely. Moreover,
>>> > even with connection timeout, clients may continue processing on
>>> > same HTTP 1.1 connections with new requests indefinitely.
>>> > Furthermore, even with HTTP 1.0 and connection timeout
>>> > hypothetical client may read answer very slow with results in very
>>> > long unpredictable closure of connection. So: yes, you code will
>>> > work but may result in very long (hours, for example) or even
>>> > indefinitely long daemon shutdown. -- Best Wishes, Evgeny Grin
>>> >
>>> >
>>> > --
>>> > Silvio Clécio
>>>
>>
>> --
>> Silvio Clécio
>>
>
>
>
> --
> Silvio Clécio
>
--
Silvio Clécio
