… | |
… | |
403 | will not restart syscalls (that includes Async::Interrupt and AnyEvent's |
403 | will not restart syscalls (that includes Async::Interrupt and AnyEvent's |
404 | pure perl implementation). |
404 | pure perl implementation). |
405 | |
405 | |
406 | Safe/Unsafe Signals |
406 | Safe/Unsafe Signals |
407 | Perl signals can be either "safe" (synchronous to opcode handling) or |
407 | Perl signals can be either "safe" (synchronous to opcode handling) or |
408 | "unsafe" (asynchronous) - the former might get delayed indefinitely, the |
408 | "unsafe" (asynchronous) - the former might delay signal delivery |
409 | latter might corrupt your memory. |
409 | indefinitely, the latter might corrupt your memory. |
410 | |
410 | |
411 | AnyEvent signal handlers are, in addition, synchronous to the event |
411 | AnyEvent signal handlers are, in addition, synchronous to the event |
412 | loop, i.e. they will not interrupt your running perl program but will |
412 | loop, i.e. they will not interrupt your running perl program but will |
413 | only be called as part of the normal event handling (just like timer, |
413 | only be called as part of the normal event handling (just like timer, |
414 | I/O etc. callbacks, too). |
414 | I/O etc. callbacks, too). |
… | |
… | |
416 | Signal Races, Delays and Workarounds |
416 | Signal Races, Delays and Workarounds |
417 | Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching |
417 | Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching |
418 | callbacks to signals in a generic way, which is a pity, as you cannot do |
418 | callbacks to signals in a generic way, which is a pity, as you cannot do |
419 | race-free signal handling in perl, requiring C libraries for this. |
419 | race-free signal handling in perl, requiring C libraries for this. |
420 | AnyEvent will try to do its best, which means in some cases, signals |
420 | AnyEvent will try to do its best, which means in some cases, signals |
421 | will be delayed. The maximum time a signal might be delayed is specified |
421 | will be delayed. The maximum time a signal might be delayed is 10 |
422 | in $AnyEvent::MAX_SIGNAL_LATENCY (default: 10 seconds). This variable |
422 | seconds by default, but can be overriden via |
423 | can be changed only before the first signal watcher is created, and |
423 | $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} or $AnyEvent::MAX_SIGNAL_LATENCY |
424 | should be left alone otherwise. This variable determines how often |
424 | - see the Ö<ENVIRONMENT VARIABLES> section for details. |
425 | AnyEvent polls for signals (in case a wake-up was missed). Higher values |
|
|
426 | will cause fewer spurious wake-ups, which is better for power and CPU |
|
|
427 | saving. |
|
|
428 | |
425 | |
429 | All these problems can be avoided by installing the optional |
426 | All these problems can be avoided by installing the optional |
430 | Async::Interrupt module, which works with most event loops. It will not |
427 | Async::Interrupt module, which works with most event loops. It will not |
431 | work with inherently broken event loops such as Event or Event::Lib (and |
428 | work with inherently broken event loops such as Event or Event::Lib (and |
432 | not with POE currently, as POE does its own workaround with one-second |
|
|
433 | latency). For those, you just have to suffer the delays. |
429 | not with POE currently). For those, you just have to suffer the delays. |
434 | |
430 | |
435 | CHILD PROCESS WATCHERS |
431 | CHILD PROCESS WATCHERS |
436 | $w = AnyEvent->child (pid => <process id>, cb => <callback>); |
432 | $w = AnyEvent->child (pid => <process id>, cb => <callback>); |
437 | |
433 | |
438 | You can also watch for a child process exit and catch its exit status. |
434 | You can also watch for a child process exit and catch its exit status. |
… | |
… | |
1010 | If AnyEvent::Log is not loaded then this function makes a simple |
1006 | If AnyEvent::Log is not loaded then this function makes a simple |
1011 | test to see whether the message will be logged. If the test succeeds |
1007 | test to see whether the message will be logged. If the test succeeds |
1012 | it will load AnyEvent::Log and call "AnyEvent::Log::log" - |
1008 | it will load AnyEvent::Log and call "AnyEvent::Log::log" - |
1013 | consequently, look at the AnyEvent::Log documentation for details. |
1009 | consequently, look at the AnyEvent::Log documentation for details. |
1014 | |
1010 | |
1015 | If the test fails it will simply return. |
1011 | If the test fails it will simply return. Right now this happens when |
|
|
1012 | a numerical loglevel is used and it is larger than the level |
|
|
1013 | specified via $ENV{PERL_ANYEVENT_VERBOSE}. |
1016 | |
1014 | |
1017 | If you want to sprinkle loads of logging calls around your code, |
1015 | If you want to sprinkle loads of logging calls around your code, |
1018 | consider creating a logger callback with the "AnyEvent::Log::logger" |
1016 | consider creating a logger callback with the "AnyEvent::Log::logger" |
1019 | function, which can reduce typing, codesize and can reduce the |
1017 | function, which can reduce typing, codesize and can reduce the |
1020 | logging overhead enourmously. |
1018 | logging overhead enourmously. |
… | |
… | |
1216 | This ensures that child processes will not see the "AE_" variables. |
1214 | This ensures that child processes will not see the "AE_" variables. |
1217 | |
1215 | |
1218 | The following environment variables are currently known to AnyEvent: |
1216 | The following environment variables are currently known to AnyEvent: |
1219 | |
1217 | |
1220 | "PERL_ANYEVENT_VERBOSE" |
1218 | "PERL_ANYEVENT_VERBOSE" |
1221 | By default, AnyEvent will be completely silent except in fatal |
1219 | By default, AnyEvent will only log messages with loglevel 3 |
1222 | conditions. You can set this environment variable to make AnyEvent |
1220 | ("critical") or higher (see AnyEvent::Log). You can set this |
1223 | more talkative. If you want to do more than just set the global |
1221 | environment variable to a numerical loglevel to make AnyEvent more |
|
|
1222 | (or less) talkative. |
|
|
1223 | |
|
|
1224 | If you want to do more than just set the global logging level you |
1224 | logging level you should have a look at "PERL_ANYEVENT_LOG", which |
1225 | should have a look at "PERL_ANYEVENT_LOG", which allows much more |
1225 | allows much more complex specifications. |
1226 | complex specifications. |
1226 | |
1227 | |
|
|
1228 | When set to 0 ("off"), then no messages whatsoever will be logged |
|
|
1229 | with the default logging settings. |
|
|
1230 | |
1227 | When set to 5 or higher (warn), causes AnyEvent to warn about |
1231 | When set to 5 or higher ("warn"), causes AnyEvent to warn about |
1228 | unexpected conditions, such as not being able to load the event |
1232 | unexpected conditions, such as not being able to load the event |
1229 | model specified by "PERL_ANYEVENT_MODEL", or a guard callback |
1233 | model specified by "PERL_ANYEVENT_MODEL", or a guard callback |
1230 | throwing an exception - this is the minimum recommended level. |
1234 | throwing an exception - this is the minimum recommended level. |
1231 | |
1235 | |
1232 | When set to 7 or higher (info), cause AnyEvent to report which event |
1236 | When set to 7 or higher (info), cause AnyEvent to report which event |
… | |
… | |
1267 | is definitely recommended to keep it off in production. Keeping |
1271 | is definitely recommended to keep it off in production. Keeping |
1268 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1272 | "PERL_ANYEVENT_STRICT=1" in your environment while developing |
1269 | programs can be very useful, however. |
1273 | programs can be very useful, however. |
1270 | |
1274 | |
1271 | "PERL_ANYEVENT_DEBUG_SHELL" |
1275 | "PERL_ANYEVENT_DEBUG_SHELL" |
1272 | If this env variable is set, then its contents will be interpreted |
1276 | If this env variable is nonempty, then its contents will be |
1273 | by "AnyEvent::Socket::parse_hostport" (after replacing every |
1277 | interpreted by "AnyEvent::Socket::parse_hostport" and |
1274 | occurance of $$ by the process pid) and an "AnyEvent::Debug::shell" |
1278 | "AnyEvent::Debug::shell" (after replacing every occurance of $$ by |
1275 | is bound on that port. The shell object is saved in |
1279 | the process pid). The shell object is saved in |
1276 | $AnyEvent::Debug::SHELL. |
1280 | $AnyEvent::Debug::SHELL. |
1277 | |
1281 | |
1278 | This happens when the first watcher is created. |
1282 | This happens when the first watcher is created. |
1279 | |
1283 | |
1280 | For example, to bind a debug shell on a unix domain socket in |
1284 | For example, to bind a debug shell on a unix domain socket in |
1281 | /tmp/debug<pid>.sock, you could use this: |
1285 | /tmp/debug<pid>.sock, you could use this: |
1282 | |
1286 | |
1283 | PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog |
1287 | PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog |
|
|
1288 | # connect with e.g.: socat readline /tmp/debug123.sock |
1284 | |
1289 | |
|
|
1290 | Or to bind to tcp port 4545 on localhost: |
|
|
1291 | |
|
|
1292 | PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog |
|
|
1293 | # connect with e.g.: telnet localhost 4545 |
|
|
1294 | |
1285 | Note that creating sockets in /tmp is very unsafe on multiuser |
1295 | Note that creating sockets in /tmp or on localhost is very unsafe on |
1286 | systems. |
1296 | multiuser systems. |
1287 | |
1297 | |
1288 | "PERL_ANYEVENT_DEBUG_WRAP" |
1298 | "PERL_ANYEVENT_DEBUG_WRAP" |
1289 | Can be set to 0, 1 or 2 and enables wrapping of all watchers for |
1299 | Can be set to 0, 1 or 2 and enables wrapping of all watchers for |
1290 | debugging purposes. See "AnyEvent::Debug::wrap" for details. |
1300 | debugging purposes. See "AnyEvent::Debug::wrap" for details. |
1291 | |
1301 | |
… | |
… | |
1351 | |
1361 | |
1352 | "PERL_ANYEVENT_MAX_OUTSTANDING_DNS" |
1362 | "PERL_ANYEVENT_MAX_OUTSTANDING_DNS" |
1353 | The default value for the "max_outstanding" parameter for the |
1363 | The default value for the "max_outstanding" parameter for the |
1354 | default DNS resolver - this is the maximum number of parallel DNS |
1364 | default DNS resolver - this is the maximum number of parallel DNS |
1355 | requests that are sent to the DNS server. |
1365 | requests that are sent to the DNS server. |
|
|
1366 | |
|
|
1367 | "PERL_ANYEVENT_MAX_SIGNAL_LATENCY" |
|
|
1368 | Perl has inherently racy signal handling (you can basically choose |
|
|
1369 | between losing signals and memory corruption) - pure perl event |
|
|
1370 | loops (including "AnyEvent::Loop", when "Async::Interrupt" isn't |
|
|
1371 | available) therefore have to poll regularly to avoid losing signals. |
|
|
1372 | |
|
|
1373 | Some event loops are racy, but don't poll regularly, and some event |
|
|
1374 | loops are written in C but are still racy. For those event loops, |
|
|
1375 | AnyEvent installs a timer that regularly wakes up the event loop. |
|
|
1376 | |
|
|
1377 | By default, the interval for this timer is 10 seconds, but you can |
|
|
1378 | override this delay with this environment variable (or by setting |
|
|
1379 | the $AnyEvent::MAX_SIGNAL_LATENCY variable before creating signal |
|
|
1380 | watchers). |
|
|
1381 | |
|
|
1382 | Lower values increase CPU (and energy) usage, higher values can |
|
|
1383 | introduce long delays when reaping children or waiting for signals. |
|
|
1384 | |
|
|
1385 | The AnyEvent::Async module, if available, will be used to avoid this |
|
|
1386 | polling (with most event loops). |
1356 | |
1387 | |
1357 | "PERL_ANYEVENT_RESOLV_CONF" |
1388 | "PERL_ANYEVENT_RESOLV_CONF" |
1358 | The absolute path to a resolv.conf-style file to use instead of |
1389 | The absolute path to a resolv.conf-style file to use instead of |
1359 | /etc/resolv.conf (or the OS-specific configuration) in the default |
1390 | /etc/resolv.conf (or the OS-specific configuration) in the default |
1360 | resolver, or the empty string to select the default configuration. |
1391 | resolver, or the empty string to select the default configuration. |