accessing a previously running site crashes dispatcher

[kaos]

It doesn't matter if the site config says enabled true or false, only requirement is that the site was running, and then later was stopped.

Expected a 404, as it gives for a site that is disabled, and was never started.

12:42:27.204 [error] gen_server z_sites_dispatcher terminated with reason: no such process or port in call to gen_server:call('z_trans_server$zhost', table)
12:42:27.207 [error] CRASH REPORT Process z_sites_dispatcher with 0 neighbours exited with reason: no such process or port in call to gen_server:call('z_trans_server$zhost', table) in gen_server:terminate/6 line 744
12:42:27.208 [error] Supervisor z_sites_sup had child z_sites_dispatcher started with z_sites_dispatcher:start_link() at <0.749.0> exit with reason no such process or port in call to gen_server:call('z_trans_server$zhost', table) in context child_terminated
12:42:27.208 [error] CRASH REPORT Process <0.775.0> with 0 neighbours exited with reason: {{noproc,{gen_server,call,['z_trans_server$zhost',table]}},{gen_server,call,[z_sites_dispatcher,{dispatch,"zhost.local:8040","/en/admin/logon",'GET',http}]}} in gen_server:call/2 line 180
12:42:27.209 [error] CRASH REPORT Process <0.2154.0> with 0 neighbours exited with reason: no such process or port in call to gen_server:call(z_sites_dispatcher, {dispatch,"zhost.local:8040","/en/admin/logon",'GET',http}) in gen_server:call/2 line 180
12:42:27.212 [error] CRASH REPORT Process <0.768.0> with 0 neighbours exited with reason: no such process or port in call to gen_server:call(z_sites_dispatcher, {dispatch,"zhost.local:8040","/en/admin/logon",'GET',http}) in gen_server:call/2 line 180
12:42:27.214 [error] CRASH REPORT Process <0.1698.0> with 0 neighbours exited with reason: no such process or port in call to gen_server:call(z_sites_dispatcher, {dispatch,"zhost.local:8040","/en/admin/logon",'GET',http}) in gen_server:call/2 line 180
12:42:27.223 [error] CRASH REPORT Process <0.767.0> with 0 neighbours exited with reason: no such process or port in call to gen_server:call(z_sites_dispatcher, {dispatch,"zhost.local:8040","/en/admin/logon",'GET',http}) in gen_server:call/2 line 180
12:42:27.225 [error] CRASH REPORT Process <0.1462.0> with 0 neighbours exited with reason: no such process or port in call to gen_server:call(z_sites_dispatcher, {dispatch,"zhost.local:8040","/en/admin/logon",'GET',http}) in gen_server:call/2 line 180
12:42:27.228 [error] CRASH REPORT Process <0.2349.0> with 0 neighbours exited with reason: no such process or port in call to gen_server:call(z_sites_dispatcher, {dispatch,"zhost.local:8040","/en/admin/logon",'GET',http}) in gen_server:call/2 line 180

[arjan]

I've seen this crash before. So you're saying it's easily reproducible?

[mworrell]

Is that after the site was restarted? Otherwise I fail to see how the dispatcher would be able to dispatch to that particular host.

[kaos]

I got a report for it, and reproduced it easily on my machine. The site was in state "stopped". Try it :p

[arjan]

You are right. Just do

z_sites_manager:stop(sitename).

and then try reload the site; it will crash.

On 13-02-14 13:29, Andreas Stenius wrote:

I got a report for it, and reproduced it easily on my machine. The site
was in state "stopped". Try it :p

—
Reply to this email directly or view it on GitHub
#714 (comment).

[arjan]

Finally managed to produce the stack trace:

(zotonic001@x1)27> [{gen_server,call,2,[{file,"gen_server.erl"},{line,180}]},
 {z_trans_server,table,1,
                 [{file,"/home/arjan/devel/zotonic/src/i18n/z_trans_server.erl"},
                  {line,71}]},
 {z_context,set_server_names,1,
            [{file,"/home/arjan/devel/zotonic/src/support/z_context.erl"},
             {line,201}]},
 {z_context,new,1,
            [{file,"/home/arjan/devel/zotonic/src/support/z_context.erl"},
             {line,156}]},
 {z_sites_dispatcher,wm_dispatch,5,
                     [{file,"/home/arjan/devel/zotonic/src/support/z_sites_dispatcher.erl"},
                      {line,569}]},
 {z_sites_dispatcher,handle_host_dispatch,3,
                     [{file,"/home/arjan/devel/zotonic/src/support/z_sites_dispatcher.erl"},
                      {line,189}]},
 {z_sites_dispatcher,handle_call,3,
                     [{file,"/home/arjan/devel/zotonic/src/support/z_sites_dispatcher.erl"},
                      {line,128}]},
 {gen_server,handle_msg,5,[{file,"gen_server.erl"},{line,588}]}]14:48:10.016 [error] gen_server z_sites_dispatcher terminated with reason: no such process or port in call to gen_server:call('z_trans_server$nmmweb', table)
14:48:10.017 [error] CRASH REPORT Process z_sites_dispatcher with 0 neighbours exited with reason: no such process or port in call to gen_server:call('z_trans_server$nmmweb', table) in gen_server:terminate/6 line 747

[arjan]

Will look into it later, no time now

[mworrell]

Apparently the stopped site is still known to the dispatcher.

[arjan]

Yes, so what's the best solution to fix this?

[mworrell]

Need to check - I think the dispatcher shouldn't "know" about any stopped site.

[arjan]

indeed so we need to reload the dispatch info when a site starts and/or stops? or is that done already?

[mworrell]

I am not sure now, will have a look at it later.

[arjan]

BTW, it crashes because z_context:new() is called on a site that is not running. That is not such bad behaviour only the crash message could be better.

[mworrell]

Solution is good - efficiency of the dispatcher is something I want to tackle later anyway. (See also the GSoC 2014 list)

[kaos]

👍